Scholarly article on 2-bromo-3-hexyl-5-nitrothiophene 69249-42-9 from Bulletin of the Chemical Society of Japan p. 371

Ó 2007 The Chemical Society of Japan

Bull. Chem. Soc. Jpn. Vol. 80, No. 2, 371–386 (2007)

371

Orientation and Substituent Eﬀects on the Properties of

the Diacetylene-Group Connected Octaethylporphyrin–

Dihexylbithiophene Derivatives (OEP–DHBTh–X)

Carrying Electron-Withdrawing Groups^#

Naoto Hayashi,¹Takashi Nishihara,¹Takuya Matsukihira,¹Hiroki Nakashima,¹

ꢀ1

Keiko Miyabayashi,²Mikio Miyake,²and Hiroyuki Higuchi

¹Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555

²School of Material Science, JAIST (Hokuriku), 1-1 Asahi-dai, Tatsunokuchi, Noumi, Ishikawa 923-1292

Received June 21, 2006; E-mail: higuchi@sci.u-toyama.ac.jp

Orientational isomers of the octaethylporphyrin–dihexylbithiophene (OEP–DHBTh) derivatives connected with a

diacetylene linkage were synthesized, with various electron-withdrawing substituents X attached at the ends. The eﬀects

of DHBTh orientation and X substituent on the properties of OEP–DHBTh–X (X ¼ H, Br, CN, CHO, and NO₂) were

studied and compared with those of related OEP derivatives.

Previously, we reported the properties of the extended con-

jugation system between octaethylporphyrin (OEP) and p-sub-

stituted benzenes (Bzn–X), both chromophores of which are

connected with a rigid and straight linkage of diacetylene

(1: OEP–Bzn–X, Chart 1).¹Based on their electronic spectra,

an intramolecular charge-transfer (IaCT) interaction between

these chromophores through the diacetylene linkage was stud-

ied and proved to be weakly induced in the derivative with elec-

tron-withdrawing X, like NO₂. Based on this ﬁnding, the elec-

tronic spectra of the conjugation system between OEP and

2-substituted 3-hexylthiophenes (2: OEP–HTh–X, Chart 1),

which is a more sophisticated system, have been examined.²

Since thiophene (Th) ring possesses the smaller resonance

energy than Bzn ring,³Th should transfer the electronic eﬀect

of X more eﬃciently through a long-distant skeleton from one

terminal site to another terminal OEP ring. In other words, the

greater IaCT phenomena would be expected in the OEP–HTh–

X system 2. In fact, the IaCT absorption bands of 2 were

observed more intensively and were proved to intensify regu-

larly in order of the electron-withdrawing abilities of X. It was

also shown that the transmission eﬃciency of the substituent

eﬀect of X to OEP in 2 enlarges nonlinearly with increasing

Hammett substituent constant ꢀ values, and yet, its transmis-

sion eﬃciency is much greater than that of the corresponding

OEP–Bzn–X derivatives of 1.

ties of its orientational isomers of various types. The reason for

introducing HTh into our system is as follows. In designing or-

ganic functional materials, the material must be thermally and

photochemically stable, have steady functions, and have easily

accessible and controllable structures of the building blocks. A

hexyl chain was incorporated into the main skeletons in conse-

quence of optimization of the material processibility and the

molecular density convenient for various optical devices, in

terms of its chain length and bulkiness.⁵MM2 calculation

clearly indicates that the ꢁ-electronic conjugation planarity

of the fundamental DHBTh units increases in order of the

orientation mode of two HTh rings in DHBTh: head-to-head

(HH) < head-to-tail (HT) < tail-to-tail (TT).^5cThe orienta-

tion of DHBTh would bring about the respective molecular pe-

culiarities, not only in the electrostatic properties but also in

the chemical reactivities and mechanistic processes as a con-

sequence (Chart 1).⁶In particular, from studies on the IaCT

donor–acceptor DHBTh system, in relation to various molecu-

lar functionalities, such as non-linear optical (NLO) behav-

iors,⁷a structure–property relationship was experimentally ob-

served between the greater third-order NLO response in the

DHBTh derivative and the higher conjugation planarity.⁸More

recently, an extended ꢁ-electronic conjugation system of

DHBTh derivatives connected with OEP has been demonstrat-

ed to ﬁgure out features that are needed for opto-electronic de-

vices.⁹OEP–DHBTh–OEP systems, connected with a diacety-

lene linkage, have unique electronic absorption bands in the

region of 400–500 nm characteristic of OEP nucleus and the

Soret band was split regularly into two main bands in response

to the orientations of DHBTh. In addition, electrochemical ex-

periments clearly showed that their electron-releasing abilities

changed with respect to the ꢁ-electronic conjugation planarity

of the DHBTh constituents.¹⁰

On the other hand, in order to develop new organic func-

tional materials for supporting the present opto-electronics, a

wide variety of well-deﬁned and well-functioned conjugation

systems based on heterocyclic nuclei, such as porphyrin and

thiophene rings, have been demonstrated, by virtue of their

high susceptibilities to optical and electronic stimulations.⁴

In relation to the intense research of the opto-electronic de-

vices, we have been studying the electronic properties of the

3,3⁰-dihexyl-2,2⁰-bithiophene (DHBTh) system, which is a di-

mer of HTh, through the comparative studies with the proper-

In our continuing investigations of the structure–property

relationship of the DHBTh derivatives, isomeric pairs of the

Published on the web February 13, 2007; doi:10.1246/bcsj.80.371

372 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

R

N

X

Ni

S

N

R=C₆H₁₃,

a: X=H, b: X=Br, c: X=CN, d: X=CHO, e: X=NO₂

2: OEP-HTh-X

1: OEP-Bzn-X

R

S

R

(HH)DHBTh

(HT)DHBTh

(TT)DHBTh

R

S

N

S

N

X

Ni

X

Ni

S

N

S

N

R

3: OEP-(HH)DHBTh-X

4: OEP-(TT)DHBTh-X

Chart 1.

OEP–DHBTh–X system 3 and 4 were synthesized, in which

the orientations of DHBTh are HH and TT modes with the

lowest and highest ꢁ-electronic conjugation planarity, respec-

tively (Chart 1). Their spectral properties were examined to

determine the orientation eﬀects of DHBTh and the substituent

eﬀects of X on the IaCT bands in this system. An aim of the

subject in this study is to evaluate the substituent eﬀect of X

quantitatively on their absorption spectral properties and then

to derive some structural requirements for enhancement of

IaCT, based on the transmission eﬃciency of substituent eﬀect

in respective conjugation systems. Taking these results togeth-

er with electrochemical experiments, the electronic properties

of 3 and 4 were elucidated. While preparing the cyano

(X ¼ CN) derivatives 3c and 4c, a curious ﬁnding due to the

orientation of DHBTh was also observed. In this paper, the

syntheses and properties of 3 and 4 are described, in terms

of orientation and substituent eﬀects on their properties, in

comparison to those of the related compounds 1 and 2.

H

X

6

1

2

R

N

H

Ni

N

H

X

S

7

5

R=C₆H₁₃,

a: X=H, b: X=Br, c: X=CN, d: X=CHO, e: X=NO₂

Scheme 1.

of Br–DHBTh–H (9a)^8,14with nitric acid–acetic anhydride

(HNO₃–Ac₂O) in good yield. Similarly, the selective transfor-

mation of Br–DHBTh–Br 9b to Br–DHBTh–CHO 9d occurred

smoothly, by displacement of Br substituent with n-BuLi and

N,N-dimethylformamide (DMF).¹⁵However, the transforma-

tion of one Br substituent of 9b to the CN group by conven-

tional methods, for example, with copper(I) cyanide (CuCN)

in reﬂuxing 1-methyl-2-pyrrolidinone (NMP), was not suc-

cessful, resulting in a complex mixture of 9c with a large quan-

tity of 9b and its dicyano product (¹H NMR and MS spectra).

In addition, the mixture could not be separated completely, un-

like a mixture of Br–HTh–Br, Br–HTh–CN, and CN–HTh–CN

derivatives (see Experimental part). As well, under much mild-

er conditions, the dibromo starting material 9b was almost re-

covered, but its reproducibility was very poor. The electrophil-

ic bromination of H–DHBTh–CN 10 with NBS in acidic media

was also unsuccessful.¹⁶After several attempts, as outlined

for the preparation of all Br–DHBTh–X derivatives 9a–9e in

Scheme 2, both 9c and 15c were successfully aﬀorded by de-

hydration from the corresponding oximes 11 and 13 of alde-

hydes 9d and 15d.¹⁷In the course of transformation of X ¼

CHO to X ¼ CN via oximes, an orientation eﬀect of DHBTh

Results and Discussion

Syntheses of 1–4. Syntheses of the OEP–Bzn–X and OEP–

HTh–X derivatives 1 and 2 were performed by the cross-

coupling reactions of OEP terminal acetylene 5 and corre-

sponding Bzn–X or HTh–X acetylenes (6 or 7) under the

Eglinton conditions (Scheme 1).^1,2,11Similarly, as summarized

in Schemes 2–4, OEP–DHBTh–X derivatives 3 and 4 were

synthesized by the reaction of 5 with corresponding DHBTh–

X acetylenes 12 or 16, respectively. DHBTh–X terminal acety-

lenes 12 and 16 were prepared from the respective bromo com-

pounds (9 and 15: Br–DHBTh–X) with trimethylsilylacetylene

(TMSA) under the Sonogashira conditions,¹²followed by

alkaline hydrolysis. Among Br–DHBTh–X, the preparation

of X ¼ CN compound 9c should be particularly noted. As is

known for electrophilic substitution reactions on Th ring,¹³

Br–DHBTh–NO₂(9e) can be obtained directly by nitration

N. Hayashi et al.

Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

373

R

S

Br

CHO

S

R

8

9b

9d

R

S

Br

CN

S

NOH

R

9a

9c

11

R

S

R

Br

S

NOH

Br

NO

CN

2

R

S

R

13

9e

10

Scheme 2.

ed by column chromatography on silica gel (SiO₂) into each

product, and their isolated yields were almost identical to the

¹H NMR spectral yields. In ¹H NMR spectra, both the peak

shapes and chemical shifts of syn- and anti-isomers are almost

the same, except for a diﬀerence in the peak shape of their OH

group. The peak due to OH proton of the syn-isomer appeared

at around ꢂ ¼ 7:6 ppm as a very sharp line, while that of the

anti-isomer appeared at the same position as a very broad line.

A similar phenomenon was observed in IR spectra, in which

the peak for ꢃ_OHof the syn-isomer (3277 cm^ꢁ1with less than

100 cm^ꢁ1half-width) was very sharp and for the anti-isomer

(ꢃ ¼ 3500{2900 cm^ꢁ1) was very broad. Similarly, the TT iso-

mer 15d aﬀorded a mixture of syn- and anti-oximes 13

(Scheme 2), and the isomers could be separated using a thin-

layer chromatography (R_f¼ 0:13 for syn-isomer and R_f¼

0:33 for anti-isomer, based on CHCl₃). The isomeric oximes

13, however, were found extremely fragile in their respective

forms in ordinary solvents. In fact, it was proved that any mix-

tures of oximes 13 in CHCl₃spontaneously changed to the

same equilibrium mixture between syn- and anti-isomers with-

in a few minutes at room temperature (see Experimental part).

Such a spectral diﬀerence between HH and TT oximes 11

and 13 also appeared in the dehydration from them in both

reactivity and yield. In the case of 11, the syn-isomer reacted

with the combined reagents of acetic anhydride and sodium

R

5

S

3

9a-e

H

X

S

R

12a-e

Scheme 3.

was observed (vide infra). The Br–DHBTh–X derivatives 9

and 15 thus obtained were readily converted with TMSA into

the corresponding DHBTh–X terminal acetylenes 12 and 16 in

good yields. Finally, oxidative couplings of the terminal acety-

lenes,¹¹i.e., 5 with 12 or 16, in the presence of copper(II) ace-

tate [Cu(OAc)₂] aﬀorded 3 and 4, respectively, in moderate

yields, together with homo-coupling dimeric products 17–21

(Chart 2). The structures of DHBTh derivatives of 1–4 were

determined by MS, IR, and ¹H NMR spectra, as well as by

elemental analyses.

Transformation of X ¼ CHO to X ¼ CN in the Br–

DHBTh–X Derivatives. The CN derivatives 9c and 15c were

prepared via oximes from the corresponding CHO derivatives

9d and 15d, respectively (Schemes 2 and 4). In the reaction of

9d with hydroxylamine (NH₂OH), an 1:1 isomeric mixture 11

of syn-oxime (R_f¼ 0:14 based on CHCl₃) and anti-oxime

(R_f¼ 0:35) was obtained. Mixture 11 could easily be separat-

R

5

S

H

X

Br

X

4

S

R

14

15a-e

16a-e

Scheme 4.

374 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

N

Ni

N

17

R

X

S

18

19

R

S

X

S

R

20

21

Chart 2.

H

O

R

N OH

H

N

O

S

Br

+

S

H

R

9d

syn-11

anti-11

1 : 1 separable mixture

- H₂O

62%

97%

9c

H

O

R

N

H

OH

O

H

N

S

Br

S

H

R

15d

syn-13

anti-13

unseparable equilibrium mixture

- H₂O

97%

15c

Scheme 5.

acetate (Ac₂O–AcONa) to form Br–DHBTh–CN 9c in 62%

yield,¹⁷while the anti-isomer reacted much faster under the

same conditions to aﬀord 9c in 97% yield. On the other hand,

the dehydration of the oxime mixture of 13 also proceeded

very smoothly, similar to the anti-oxime of 11, to produce the

corresponding CN derivative 15c almost quantitatively.

These results could be ascribed to the structural diﬀerence

between oximes 11 and 13. The syn-oxime produces additional

stabilization energy through an intramolecular hydrogen bond-

ing between OH group and sulfur atom of HTh ring, which

should be greater than that produced into the anti-oxime

through an intermolecular hydrogen bonding (Scheme 5). In

other words, it is deducible that the intramolecular hydrogen

bonding plays a crucial role in the isolation of the syn-oxime

of 11 from the anti-isomer. On the other hand, in the case of

syn-oxime 13, such an intramolecular hydrogen-bonding inter-

action for its thermal stability is rather to force the molecule

into a restricted geometry, where additional steric repulsion

between C–H bond on the oxime moiety and hexyl substituent

on the HTh ring arises to compete with the intramolecular

N. Hayashi et al.

Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

375

R

Hc

Hb

Ha

N

X

Ni

X

Ni

S

N

a: X=H, b: X=Br, c: X=CN, d: X=CHO, e: X=NO₂

1

2

R

Hd

Hf

R

S

N

S

N

X

Ni

X

Ni

S

N

S

N

R

He

Hg

R

3

4

Hj

Hh

Hi

Hk

X

S

22: Bzn-X

23: Th-X

Chart 3.

hydrogen-bonding interaction. These antithetical interactions

in the syn-oxime 13 cause the molecule to be much reactive.

Instead, the anti-isomer would eliminate the sterical disadvant-

age by rotating the hydroxyimino group about a pinch bond to

some degree, though the ꢁ-electronic conjugation for stabili-

zation between C=N bond and Th ring is cut oﬀ as a conse-

quence. Therefore, in the case of oximes 13, it is concluded

that the intramolecular hydrogen bonding of OH group with

sulfur atom of HTh ring makes the free energy diﬀerence be-

tween syn- and anti-isomers less making it diﬃcult to isolate

each of them.

It should be noted that several molecular peculiarities due to

the steric interaction of the hexyl group with additional sub-

stituents in the molecule have been curiously observed till

now in the DHBTh derivatives of various types, especially

in the DHBTh derivatives with TT orientation.^6,18The phe-

nomenon introduced above is exactly the one reﬂecting the

orientation of the DHBTh constituent in the molecule (also

see below).

¹H NMR Spectra. ¹H NMR spectra were very useful for

making not only the structure determination of the molecules

but also the orientation and substituent eﬀects on the series

of speciﬁc protons conﬁrmed precisely, because of the rigid

and simple structural system of the derivatives connected

with the diacetylene linkage. Therefore, each proton could

be easily assigned. All of the chemical shifts due to meso pro-

tons (meso-H) of the OEP ring in 1–4 were nearly the same

(ꢂ ¼ 9:4 ꢂ 0:03 ppm), clearly indicating that any substituents

possess no ability enough to aﬀect the ring current of OEP, ap-

parently due to the long distance between them. On the other

hand, series of Bzn- and Th-protons (Bzn–H and Th–H) near

the substituents X exhibited their characteristic behaviors, de-

pending on their individual circumstances, as is seen in the

case of monosubstituted Bzn–X and Th–X derivatives 22

and 23 (Chart 3). It is well known that Hi series at the position

next to X in 22 shifts toward the lower ﬁeld from 7.25 ppm

(a: X ¼ H, in CDCl₃) regularly by the following magnitudes:

0.00 ppm for X ¼ Br, 0.30 ppm for X ¼ CN, 0.73 ppm for

CHO, and 0.97 ppm for X ¼ NO₂.¹⁹Similarly, Hk series at

the 3-position in 23 shifts from 7.10 ppm (a: X ¼ H, in CDCl₃)

by the following magnitudes: ꢁ0:05 ppm for X ¼ Br, 0.47

ppm for X ¼ CN, 0.65 ppm for X ¼ CHO ppm, and 0.82 ppm

for X ¼ NO₂.²⁰It is shown that X ¼ Br scarcely aﬀects on the

chemical shifts of both Hi and Hk, which is almost identical to

X ¼ H in magnetic aﬀection. In other words, the substituent

eﬀects involving 22 and 23 substantially have the same trend,

though the changes in the chemical shifts from the standard

ones 22a and 23a are diﬀerent in magnitude between Hi

(ꢀꢂ ¼ 0:00{0:97 ppm) and Hk (ꢀꢂ ¼ ꢁ0:05{0:82 ppm) se-

ries. There was almost no change in the chemical shifts for

Hh at the meta-position in 22 are almost unchanged. It is also

interesting to note that among substituents X, only CN group

aﬀects the Th ring more strongly than the Bzn ring, resulting

in nearly the same chemical shifts for Hi of 22c and Hk of

23c. These results should be ascribed not only to a structural

diﬀerence between six-membered carbocyclic ring and ﬁve-

membered heterocyclic ring, but also to a magnetic diﬀerence

between ring currents of Bzn and Th nuclei.²¹

All of the chemical shifts for Th–H and Bzn–H in 1–4 were

plotted against the substituents X, temporarily applying the

changes in chemical shifts for Hi series in 22 or for Hk series

in 23 as a measure of the substituent eﬀects of X (Figs. 1 and

2). In the case of OEP–Bzn–X 1, Ha series shifted in the region

ꢂ ¼ 7:62{7:77 ppm with changing X, while Hb series shifted

in the region ꢂ ¼ 7:37{8:26 ppm along an imaginary line in-

volving Hi series. This result apparently indicates that Hb se-

ries adjacent to X are strongly aﬀected, shifting toward lower

ﬁelds on going from X ¼ H to X ¼ NO₂. The former Ha series

are inherently much less aﬀected by the substituents, similar to

Hh series at the meta-position of 22, simply reﬂecting the

anisotropic eﬀect of the diacetylene linkage to resonate at the

relatively low ﬁelds in a very narrow region. As is generally

known for Hi series in 22, in addition to an electron-withdraw-

ing eﬀects of X on the ortho-position, an anisotropic eﬀect of

376 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

The trend in chemical shift changes for Th–H series in 23

was similarly and explicitly observed for that of the OEP–

DHBTh–X systems 3 and 4 (Fig. 2). In the respective Th–H

series attached on HTh ring linked with the diacetylene, Hd se-

ries appeared in the region ꢂ ¼ 7:27{7:31 ppm for HH isomer

3 and Hf series in the region ꢂ ¼ 6:88{7:05 ppm for TT isomer

4, indicating that each Th–H series exists in the very similar

magnetic circumstance and are substantially free from aﬀec-

tions of X. In the case of Th–H series attached to the HTh ring

linked with the substituents X, the chemical shifts for Hg series

in 4 are comparable to those for Hj series in 23, and thus, the

two proton series are similar to each other, with the changes in

the chemical shift in the narrow region ꢂ ¼ 6:84{7:16 ppm. On

the other hand, as expected, substituent eﬀects were clearly ob-

served for only He series in 3, with the changes in the chemical

shift in the region ꢂ ¼ 6:98{7:82 ppm, with a high similarity to

the behavior of Hk series. It is also notable that the chemical

shifts for He series are all observed in an in-between region

of the Hc and Hk series. Since the Th ring is generally regard-

ed as an electron-donative nucleus,²²He series should appear

at higher ﬁelds than the corresponding Hc series, if shielding

eﬀect was only considered. Therefore, this reversed result

could be ascribed to that the 2-substituted HTh ring in 3 recov-

ers its ring current with a greater magnitude consequently, as

compared with that in 2, because the electron-withdrawing di-

acetylene linkage is located far away from the 2-substituted

HTh ring moiety.

Although a linear correlation between substituents and the

changes in chemical shifts for Bzn–H and Th–H was observed,

it seemed parameters like, Hammett substituent constant ꢀ val-

ues, could not be applied in these systems. As is generally the

case, a hard correlation between substituent eﬀects on Bzn–H

and Th–H adjacent to X and certain ꢀ values involves addi-

tional factors, such as steric and electronic interactions be-

tween X and peripheral substituents on the respective rings.

With such a restricted structural situation around the ortho-po-

sition of X, the substituent eﬀect would not appear in all the

derivatives with the same eﬃciency. Thus, the substituent ef-

fects in 1–4 were relatively compared with those in 22 and

23, based on the chemical shift changes for Hi or Hk series

as the imaginary substituent constant ꢀ values for X. As given

in Equations 1–4, among Bzn–H and Th–H, Hb, Hc, He, and

Hg series possess the fairly high similarity in substituent eﬀect

to Hi or Hk series with correlation factors R of greater than

0.96. The substituent eﬀect of X transfers comparably onto

these four series of 1–4 in the very similar mechanism to that

in the standard compound 22 or 23, with various eﬃciencies

depending on their individual circumstances. The substituent

eﬀect on Hb series in 1 is described by that of Hi series with

84% eﬃciency (Eq. 1). In particular, it is evident in a quanti-

tative sense that both Hc and He series exist in the same mag-

netic circumstance as Hk series (Eqs. 2 and 3), as could also be

deduced from Fig. 2.

δ /ppm

8.4

1: OEP-Bzn-X (Ha)

•

1: OEP-Bzn-X (Hb)

22: Bzn-X (Hh)

22: Bzn-X (Hi)

8.2

8

•

7.8

7.6

7.4

7.2

•

0

-0.2

0.2

0.4

0.6

0.8

1

1.2

(δ_Hi- 7.25) /ppm

Fig. 1. Plots of chemical shifts of respective series of pro-

tons: Ha and Hb of 1 and Hh of 22, against the shifting

values of Hi series of 22. 0.00 ppm for X ¼ Br, 0.30 ppm

for X ¼ CN, 0.70 ppm for X ¼ CHO, and 0.97 ppm for

X ¼ NO₂were used as a measure of the substituent eﬀects

of X, based on 7.25 ppm of Hi of 22a.¹⁹

δ /ppm

8.2

2: OEP-HTh-X (Hc)

•

3: OEP-(HH)DHBTh-X (Hd)

3: OEP-(HH)DHBTh-X (He)

4: OEP-(TT)DHBTh-X (Hf)

4: OEP-(TT)DHBTh-X (Hg)

23: Th-X (Hk)

8

7.8

7.6

7.4

7.2

7

•

6.8

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

(δ _Hk- 7.10) /ppm

Fig. 2. Plots of chemical shifts of respective series of pro-

tons: Hc, Hd, He, Hf, and Hg of 2, 3, and 4, against the

shifting values of Hk series of 23. ꢁ0:05 ppm for X ¼

Br, 0.47 ppm for X ¼ CN, 0.65 ppm for X ¼ CHO, and

0.82 ppm for X ¼ NO₂were used as a measure for the

substituent eﬀects of X, based on 7.10 ppm of Hi of 23a.²⁰

the substituents carrying unsaturated bonds, such as X ¼ CN,

CHO, and NO₂, induces Hb series in 1 to change more drasti-

cally. The chemical shifts due to Ha and Hb in OEP–Bzn–CN

1c were nearly the same, proving that the magnetic inﬂuences

on Bzn–H are almost comparable between the CN substituent

and the diacetylene-group connected OEP constituent.

In the case of OEP–HTh–X 2, the chemical shift changes for

Hc series were considerably correlated with those for Hk series

in 23, apparently showing that the substituent eﬀect on Th ring

of 23 holds purely in parallel on HTh ring of 2. A series of Hc,

however, all resonate at the higher ﬁelds (ꢂ ¼ 6:91{7:74 ppm),

as compared with the corresponding Hk series. This result

might be ascribed to a reduction in the HTh ring current of

2 due to the multiple substituents on it, rather than to a com-

bined shielding eﬀect of the diacetylene linkage as an elec-

tron-withdrawing substituent and the hexyl group as an elec-

tron-donating substituent on Hc series (vide infra).

ꢂ ¼ 0:84ꢀ þ 7:38 (R = 0.961, for the Hb series)

ꢂ ¼ 1:01ꢀ þ 6:91 (R = 1.000, for the Hc series)

ꢂ ¼ 1:02ꢀ þ 6:91 (R = 0.998, for the He series)

ꢂ ¼ 0:37ꢀ þ 6:88 (R = 0.968, for the Hg series)

ð1Þ

ð2Þ

ð3Þ

ð4Þ

Although the changes in the chemical shift for Hj series at

N. Hayashi et al.

Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

377

ε/10⁵

(a)

ε/10⁵

(b)

1.0

0.5

0.0

0.5

0.0

300

ε/10⁵

(c)

400

500

600

700

300

400

500

600

700

λ/nm

ε/10⁵

(d)

1.0

0.5

0.0

0.5

0.0

300

400

500

600

700

300

400

500

600

700

λ/nm

Fig. 3. Electronic absorption spectra for pairs of the X ¼ H and X ¼ NO₂derivatives in respective systems (CHCl₃, 25 ^ꢃC). (a) is

for 1a (broken line) and 1e (solid line), (b) is for 2a (broken line) and 2e (solid line), (c) is for 3a (broken line) and 4a (solid line),

and (d) is for 3e (broken line) and 4e (solid line).

the 4-position in 23 show no regular trend upon changing X:

ꢁ0:27 ppm for X ¼ Br, 0.00 ppm for X ¼ CN, 0.10 ppm for

X ¼ CHO, and ꢁ0:03 ppm for X ¼ NO₂,²⁰while Hg series

in 4 behaved similarity to Hk series (Eq. 4). The reason for such

a high similarity in chemical shift changes between Hg and Hk

series is not understood at present. The substituent eﬀect on Hg

series, however, is fairly small (37% transmission eﬃciency

based on Hk series), probably due to their distance from X.

N

Ni

N

24

25

Chart 4.

1

ꢀ

Electronic Absorption Spectra.

Electronic absorption

in their H NMR spectra. With respect to Q bands (n ! ꢁ

spectral measurements were performed in CHCl₃at room tem-

perature, unless otherwise stated. Selected spectra of respec-

tive pairs of derivatives with substituents a: X ¼ H and e: X ¼

NO₂in 1–4 are shown in Fig. 3. Among them, Figures 3c and

3d show a pair of 3a and 4a and a pair of 3e and 4e, respec-

tively, for convenience sake.

transitions), derivatives 1a and 2a exhibited much broader

bands with less intensity, as compared to derivatives 1e and

2e. In the case of 3 and 4, Q bands of the (TT)DHBTh deriva-

tives are slightly sharper and more intense than those of the cor-

responding HH isomers, with longer tailing.

From a previous study, the diacetylene linkage eﬃciently

shifts the maximum of Soret band of OEP (24; ꢄ_max¼ 393

nm in CHCl₃)²⁴by 35 nm without altering the electronic struc-

ture, suggesting that the diacetylene linkage in 25 (ꢄ_max¼ 428

nm)^1,25is an inductive substituent rather than part of the ꢁ-

electronic conjugation (Chart 4). Similarly, the connection of

the diacetylene-group OEP derivative 25 to other chromo-

phores, such as Bzn and HTh moieties, at the terminal position

caused further bathochromism in the Soret band maximum,

which shifted by another 7 nm for 1a and 16 nm for 2a. This

result shows that the HTh ring system electronically interacts

with OEP through the diacetylene linkage more intensively.

The terminal HTh constituents in 3, however, exhibited no

longer aﬀection on the OEP ring, distinct from those in 4,

clearly indicating that the high ꢁ-electronic conjugation pla-

narity of DHBTh in the molecular system is very important

for electronic communication between such far-distant separat-

ed chromophores (vide infra).

The X ¼ NO₂derivatives 1e, 2e, and 4e exhibit much diﬀer-

ent spectra from the corresponding X ¼ H derivatives 1a, 2a,

and 4a, aﬀording much broad absorption curves, distinct from

the case of a pair of 3a and 3e. Almost symmetrical Soret bands

ꢀ

(ꢁ ! ꢁ transitions) of 1a and 2a showed a tendency to split

into two or three main bands, when X ¼ H is replaced with

the more electron-withdrawing substituents toward X ¼ NO₂,

respectively, with a reduction in their intensities. In the case

of 3, the Soret bands were nearly the same between 3a and 3e

in both absorption maximum and shape, appearing in single ab-

sorption curves (Figs. 3c and 3d). On the other hand, the Soret

band for 4a is split into two clear bands,²³while the Soret band

for 4e is almost one broad band with a slightly distorted shape

in CHCl₃. It was also shown that the spectra of X ¼ Br deriv-

atives are similar to those of X ¼ H derivatives for each series

and that the other X ¼ CN and CHO derivatives had spectra in-

between those of the X ¼ H and NO₂derivatives, as is seen

378 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

Table 1. Solvent Dependent Absorption Maxima (ꢄ/nm)

Due to IaCT Bands of the Nitro Derivatives of 1–4

λ

_max/nm

500

1: OEP-Bzn-X

•

ꢀE/kcal mol^ꢁ1

2: OEP-HTh-X

490

OEP derivatives

Hexane

Acetonitrile

•

480

4: OEP-(TT)DHBTh-X

1e

2e

3e

4e

459

483

442

488

445

453

440

468

1.92

3.85

0.29

2.45

•

470

•

460

•

450

•

440

•

430

420

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

Imaginary σ values

Fig. 5. Plots of IaCT band maxima of 2 and 4, based on

IaCT bands of 1 (CHCl₃, 25 ^ꢃC). For linear correlation be-

tween IaCT band and substituent eﬀect, ꢀ values for X of

1 were deﬁned by using ꢄ_max¼ 435 nm of 1a as 0.00 for

X ¼ H (Br), 0.25 for X ¼ CN, 0.50 for X ¼ CHO, and

1.00 for X ¼ NO₂with ꢅ ¼ 20:0 (R ¼ 1:000).

300

400

500

600

700

λ/nm

skeletons between 1–4, their IaCT bands were plotted against

the estimated ꢀ values (Fig. 5), and curve ﬁtting of ꢄ-ꢀ corre-

lations for 2 and 4 led to the fairly high linear relationships

between them (Eqs. 6 and 7).

Fig. 4. Electronic absorption spectra of 2e in hexane (bro-

ken line) and in acetonitrile (solid line).

It should be noted that the orientation of DHBTh also plays

a critical role in the external conjugation with the 18 ꢁ-elec-

tronic conjugation ring system of OEP through the diacetylene

linkage, which splits the Soret band into two or three bands.²⁶

The splitting in the Soret bands were found to be aﬀected by

both the substituents and solvent polarities, i.e., a larger batho-

chromic shift was observed with a stronger electron-with-

drawing X and with less polar solvents.^1,2,8,23,27Accordingly,

these bands were assigned as IaCT bands, indicating that the

OEP derivatives in these systems are more polarized in the

ground state.²⁶The IaCT bands of 1e–4e in hexane (non-polar)

and acetonitrile (polar) solvents are summarized in Table 1,

and the spectra for 2e are shown in Fig. 4. Since no particular

spectral changes were observed upon changing not only sub-

stituents but also solvent polarities for all the derivatives 3,

which is similar to 24 and 25, the substituents X have negligi-

ble aﬀect on 3. Therefore, it could be concluded that the elec-

tronic structures of OEP nuclei in these diacetylene-group con-

nected conjugation systems are sensitive to the solvent polarity

in order of 2e > 4e > 1e ꢄ 3e.

ꢄ ¼ 435 þ 20:0ꢀ (R = 1.000, for series 1)

ꢄ ¼ 444 þ 35:0ꢀ (R = 0.999, for series 2)

ꢄ ¼ 461 þ 22:9ꢀ (R = 0.965, for series 4)

ð5Þ

ð6Þ

ð7Þ

Based on these results, the substituent eﬀect in 2 transmits

to the terminal OEP electronic system through the diacetylene

linkage mechanistically in the same manner to the OEP elec-

tronic system as in 1. Yet, the transmission eﬃciency of the

substituent eﬀect in 2 is 1.75 (35.0/20.0) times greater in the ꢄ

value (1.65 times greater in energy value) than that in 1. This

result could be attributed to the cyclic 6ꢁ-electron conjuga-

tion system of both Bzn and Th nuclei but to the smaller reso-

nance energy of the Th ring, which is eventually almost com-

parable to the diﬀerence in an aromaticity index, estimated as

ISE scale, between the Bzn (58.20 kcal mol^ꢁ1) and Th (32.54

kcal mol^ꢁ1) rings.²⁹On the other hand, the linear correlation

factor R for the derivatives of 4 was slightly small (0.965),

and a turning point in the substituent eﬀect was clearly ob-

served at X ¼ CN. In the conjugation system of 4, two types

of electronic interactions of OEP with the (TT)DHBTh constit-

uent vs with the X substituents might aﬀect their IaCT bands

concurrently. The above result suggests that the interaction

of OEP with X is dominant over the interaction with the

DHBTh constituent, in the derivatives that have X with ꢀ val-

ues greater than 0.25 (also see below). It is also noted that the

transmission eﬃciency of the substituent eﬀect on the IaCT

bands is still almost comparable in energy value range be-

tween 1 (2.9 kcal mol^ꢁ1from X ¼ H to X ¼ NO₂) and 4 (2.8

kcal mol^ꢁ1), in spite of the longer distance between OEP and

X in 4. This result apparently indicates the greater susceptibil-

ity of Th ring to outside stimulations, such as X and solvent

eﬀects. Furthermore, it was found that the substituent eﬀect

(X ¼ H/NO₂) on IaCT bands is comparable to the solvent ef-

According to Rao, the maxima due to the IaCT bands in

the donor–acceptor Bzn derivatives, such as p-substituted ani-

lines and anisoles, are well known to correlate linearly with

Hammett substituent constant ꢀ values.²⁸However, similar

to the ¹H NMR spectral study, no adequate set of ꢀ values

have been reported to the best of our knowledge until now,

which can be used for the systems 1, 2, and 4. Thus, simply

applying Rao’s equation (ꢄ ¼ ꢄ₀þ ꢅꢀ) to IaCT bands of 1,

imaginary ꢀ values for X were estimated from their Soret band

maxima based on 1a (ꢄ_max¼ 435 nm) in order to establish a

linear correlation between them, aﬀording ꢀ ¼ 0:00 for X ¼

H (Br), 0.25 for X ¼ CN, 0.50 for X ¼ CHO, and 1.00 for

X ¼ NO₂with ꢅ ¼ 20:0; the absorption maximum of 1a is

completely the same as that of 1b (Eq. 5). In view of the same

N. Hayashi et al.

Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

379

Table 2. Half-Wave Oxidation Potentials (/mV)^a)of Substituted OEP Derivatives 1–4 and Related Com-

pounds 24 and 25

E₁¹⁼²

OEP derivatives

E₂¹⁼²

a: X ¼ H

915

1280

900

b: X ¼ Br

915

1285

910

c: X ¼ CN

d: X ¼ CHO

e: X ¼ NO₂

1

2

940

1310

930

975

1350

940

1010

1390

950

1260

910

1280

915

1250

920

1290

930

1300

920

3

1280

870

1210

880

1260

980

1300

910

1270

910

4

1240

1200

1360

1260

1190

24

25

860

1320

910

1280

a) Oxidation potentials were measured by cyclic voltammetry in CH₂Cl₂containing n-Bu₄NClO₄. GC

31

(working E), Pt (counter E), and SCE (reference E). Scan rate; 120 mV s^ꢁ1

.

fect (hexane/acetonitrile) in terms of energy value range, in

these diacetylene-group connected OEP derivatives.

systems heightens their oxidation E₁values regularly, and

thus, lowers their electron-releasing abilities with an increase

in the electron-withdrawing properties of X. It is also noted

that the transmission eﬃciency of the substituent eﬀect on

the HOMO is greater in the Bzn system (ꢀE₁¼ 95 mV from

X ¼ H to X ¼ NO₂) than in the HTh system (ꢀE₁¼ 50 mV).

Taking their electronic spectral results into consideration,

this fact reversely indicates that the substituent eﬀect on the

LUMO is more prominent in the system of 2 consequently.

As expected, the OEP–(HH)DHBTh–X system 3 exhibited

almost the same E₁values in such a narrow region of 910–

920 mV for each X derivatives, showing that neither conjuga-

tion interaction eﬀect nor substituent eﬀect transfer to the OEP

ring because the (HH)DHBTh constituent is distorted, which

supports the results from the electronic spectra. On the other

hand, the OEP–(TT)DHBTh–X system 4 showed a peculiar

trend in the substituent eﬀect on their HOMO, diﬀerent from

the systems 1 and 2. Because of the highly conjugated planar-

ity of (TT)DHBTh, the E₁values of 4 were expected to height-

en regularly with an increase in the electron-withdrawing abil-

ities of X. In fact, the E₁values of the ﬁrst three derivatives 4a,

4b, and 4c increased in order. However, the E₁values of the

rest derivatives 4d and 4e lowered to be almost equal to those

of the X ¼ H derivatives in the other systems. It is also noted

that only in the case of 4, the X ¼ CHO and NO₂derivatives

possess higher electron-releasing abilities than the X ¼ CN de-

rivative. The diﬀerence in the substituent eﬀect on the HOMO

in 4 can be explained by the fact that an sp²-atom containing

X, such as CHO and NO₂, can not avoid the steric repulsion

with the nearby bulky hexyl group on the terminal HTh ring.

Thus, certain substituents X are distorted from the conjugation

plane with HTh, resulting in a resonance interdiction between

them more or less. Up to now, curious phenomena due to the

steric repulsion of this type have been observed occasionally

for the TT isomer of the DHBTh derivatives in terms of elec-

tron-transfer processes³³and conformational changes,^6,18as

well as the dehydration reactivities from isomeric DHBTh

oximes (vide ante).

Oxidation Potentials. Porphyrins are highly susceptible to

optical and electrochemical stimulations to produce corre-

sponding radical cations by releasing one electron, with which

versatile sensitization functions are driven in various living

bodies including photo-synthetic reaction center.³⁰Thus, in

this study, the oxidation potentials of the OEP derivatives in

1–4 were measured by cyclic voltammetry for estimation of

the substituent eﬀect on their electron-releasing ability in di-

chloromethane (CH₂Cl₂) (Table 2).³¹All of the OEP deriva-

tives including 24 and 25 exhibited the reversible redox waves

in the potential region between 860 and 1390 mV vs SCE, with

two one-electron releasing processes toward the corresponding

dicationic species. Based on the result (E₁¼ 910 mV) of 25,

the diacetylene linkage proves to heighten the ﬁrst oxidation

potential (E₁¼ 860 mV) of 24, indicating the electron-with-

drawing ability of the diacetylene linkage to lower the HOMO

of 24. The HOMO of OEP is a non-bonding level involving

four peripheral N atoms of OEP.³²The diacetylene linkage,

however, can be rather regarded as an inductive substituent

and, thus, lowers the LUMO of OEP more eﬃciently, since

not only Soret but also Q bands of 25 appeared at the much

longer wavelengths than the respective bands of 24. Similarly,

the E₁values of 1a and 2a are almost equal to that of 25, in-

dicating that the ꢁ-electronic conjugation interaction between

OEP and Bzn or HTh nuclei through the diacetylene linkage

aﬀects mostly the LUMO of 24, but not its HOMO so much.

There is a relatively large diﬀerence in the E₁values of 3a

and 4a, proving that the terminal HTh ring of the (TT)DHBTh

constituent in 4 participates eﬃciently in the ꢁ-electronic

conjugation interaction with OEP to elevate its HOMO. In this

respect, the terminal HTh ring of the (HH)DHBTh constituent

in 3 is just regarded as a sterical substituent, due to the highly

distorted conjugation plane of DHBTh, showing that the eﬀect

of (HH)DHBTh on the HOMO is almost comparable to a t-

butyl group.

Introduction of X into the OEP–Bzn–H and OEP–HTh–H

380 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

R

Conclusion

S

N

X

Ni

S

N

According to the synthetic procedures for the OEP–Bzn–X

derivatives 1, series of OEP–HTh–X and OEP–DHBTh–X de-

rivatives 2, 3, and 4 were successfully synthesized, utilizing

oxidative couplings of the corresponding terminal acetylenes.

In the course of synthetic study for OEP–DHBTh–CN 3c

and 4c via oximes 11 and 13, the hydroxyimino moiety was

found to participate not only in an intramolecular hydrogen-

bonding interaction with the sulfur atom of HTh ring but also

in a sterically repulsive interaction with the hexyl group. This

structural situation in antithetical interactions results in a char-

acteristic diﬀerence in their stability and reactivity between

syn- and anti-oximes. Substituent eﬀects appear in the structur-

al and spectral properties in relation to the electron-withdraw-

ing abilities of X. The substituent eﬀect was clearly observed

in ¹H NMR spectra of the three series of Hb, Hc, and He,

which is comparable to the corresponding series of Hi and

Hk in 22 and 23. Unexpectedly, the chemical shifts for Hg

in 4 also changed linearly with the electron-withdrawing abil-

ities of X, in contrast to those for Hj at the 4-position in 23. In

particular, the electronic absorption spectra were aﬀected in-

tensively not only by the substituent eﬀect but also by the ori-

entation of DHBTh. Using estimated ꢀ values based on the

IaCT bands in 1, the maxima of IaCT bands in 2 proved to

change regularly and exactly in the same mechanism as those

in 1. The (HH)DHBTh system 3 exhibited no particular rela-

tionship between X and their IaCT band maxima, while the

maxima for the (TT)DHBTh system 4 changed regularly sim-

ilar to those in 1. These facts clearly show that the substituent

eﬀect can be eﬃciently transmitted to the electronic properties

of OEP by increasing the molecular planarity even in such a

long-distant conjugation system. In addition, it is concluded

that the transmission eﬃciencies of substituent eﬀect on both

¹H NMR and electronic spectra were greater in the HTh and

DHBTh derivatives than in the corresponding Bzn derivatives,

indicating that the smaller resonance energy of the Th ring

makes it easier to be aﬀected by the outside stimulations as

well. The combined analysis of the absorption spectra with

the electrochemical experiments revealed that the electron-

withdrawing substituent eﬀect appears mostly on the LUMO

of OEP more intensively than on its HOMO, though both

HOMO and LUMO undoubtedly lower their energy levels.

Several trials for linear correlation of substituent constant ꢀ

values with the ﬁrst oxidation potential E₁value, as a measure

of electron-releasing ability from the HOMO, met without suc-

cess, but the trends in substituent eﬀect on E₁values were

uniquely observed in the present series of OEP derivatives.

Among them, both 1 and 2 decreased their electron-releasing

abilities in order with the electron-withdrawing properties of

X. And, the changes in the E₁value between the X ¼ H and

X ¼ NO₂derivatives conclude that the substituent eﬀect is

transmitted to the HOMO with a greater eﬃciency in the

Bzn system 1 and to the LUMO with a greater eﬃciency in

the HTh system 2. In the case of 3, a trend in substituent eﬀect

on E₁values was not particularly observed. Although the E₁

values for the derivatives of 4 were expected to increase in or-

der of the electron-withdrawing abilities of X due to the high

conjugation planarity of (TT)DHBTh, no regular trend in sub-

R

26: OEP-(TH)DHBTh-X

Chart 5.

stituent eﬀect was observed. This suggests a resonance inter-

diction between X with HTh ring arising from steric repulsion

with the hexyl group. In order to verify the irregular trend in

the substituent eﬀect in 4, further investigations are under

way with a new series of long-distant conjugation derivatives,

OEP–(TH)DHBTh–X (26, Chart 5).³⁴

Experimental

Melting points were determined on a hot-stage apparatus and

are uncorrected. IR spectra were measured on a Jasco FT/IR

7300 spectrophotometer as KBr disk or neat sample; only signiﬁ-

cant absorptions are reported in ꢃ values (cm^ꢁ1). EI and FAB

mass spectra were recorded with a JEOL JMS-700 spectrometer.

¹H NMR spectra were measured in CDCl₃solution at 25 ^ꢃC on

a JEOL JMN-ECP 600 (600 MHz) spectrometer and were record-

ed in ꢂ value (ppm) with TMS as an internal standard. The cou-

pling constants (J) are given in Hz. Electronic absorption spectra

were measured in CHCl₃solution on a Shimadzu UV-2200A

spectrophotometer and were recorded in ꢄ_maxvalues (nm, sh =

^{shoulder) and molar extinction coeﬃcients (}"), unless otherwise

stated. CV was performed on a BAS CV-27 potentiometer in

CH₂Cl₂solution in the presence of n-Bu₄NClO₄at a scan rate

of 120 mV s^ꢁ1

31

.

SiO₂(Fujisilysia BW 820MH or BW 127ZH)

and aluminum oxide (Al₂O₃, CAMAG 504-C-1) were used for

column chromatography. THF was distilled over calcium hydride

and then over sodium diphenylketyl under argon (Ar) atmosphere

before use. The reactions were followed by TLC aluminum sheets

precoated with Merck SiO₂F₂₅₄or with Merck Al₂O₃GF₂₅₄

Organic extracts were dried over anhydrous sodium sulfate or

magnesium sulfate prior to removal of the solvents.

.

2-Bromo-5-cyano-3-hexylthiophene.

Method A (reaction

with CuCN); a solution of 2,5-dibromo-3-hexylthiophene¹⁴(103

mg, 0.316 mmol) and CuCN (28.4 mg, 0.317 mmol) in NMP

(3.0 cm³) was stirred at 120–125 ^ꢃC over 30 h. The reaction mix-

ture was poured into 25% ammonia aqueous solution and was ex-

tracted with CHCl₃. The extracts were washed with brine and then

dried. The residue obtained after removal of the solvent was chro-

matographed on SiO₂(1:7 ꢅ 80 cm) with hexane–CHCl₃(4:1) to

aﬀord 5-bromo-2-cyano-3-hexylthiophene (8.6 mg, 10%), 2-bro-

mo-5-cyano-3-hexylthiophene (12 mg, 14%), and 2,5-dicyano-3-

hexylthiophene (6.9 mg, 10%) in order, together with 2,5-dibro-

mo-3-hexylthiophene (44 mg). 5-Bromo-2-cyano-3-hexylthio-

phene: Yellow oil. MS; m=z 271, 273 (M^þ, M^þþ 2, based on

⁷⁹Br) for C₁₁H₁₄BrNS. IR; 2955, 2930, and 2860 (CH), 2220

1

(CN). H NMR; 6.95 (1H, s, Th–H), 2.74 (2H, t, J ¼ 8 Hz, CH₂-

(CH₂)₄CH₃), 1.70–1.20 (8H, m, CH₂(CH₂)₄CH₃), 0.89 (3H, t,

J ¼ 7 Hz, CH₃). UV–vis; 265 (12000). Found: C, 48.44; H, 5.33;

N, 5.10%. Calcd for C₁₁H₁₄BrNS: C, 48.52; H, 5.18; N, 5.15%.

2-Bromo-5-cyano-3-hexylthiophene: Yellow oil. MS; m=z 271,

273 (M^þ, M^þþ 2, based on ⁷⁹Br) for C₁₁H₁₄BrNS. IR; 2955,

1

2930, and 2860 (CH), 2220 (CN). H NMR; 7.31 (1H, s, Th–H),

2.80 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.70–1.25 (8H, m, CH₂-

(CH₂)₄CH₃), 0.89 (3H, t, J ¼ 7 Hz, CH₃). UV–vis; 248 (7800),

N. Hayashi et al.

Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

381

256 (7700), 282 (10500). Found: C, 48.36; H, 5.22; N, 4.97%.

Calcd for C₁₁H₁₄BrNS: C, 48.52; H, 5.18; N, 5.15%. 2,5-Dicya-

no-3-hexylthiophene:^14aMS; m=z 219 (M^þþ 1) for C₁₂H₁₄N₂S.

IR; 2950, 2925, and 2860 (CH), 2225 (CN). ¹H NMR; 7.46 (1H, s,

Th–H), 2.80 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.70–1.25 (8H, m,

CH₂(CH₂)₄CH₃), 0.89 (3H, t, J ¼ 7 Hz, CH₃).

phene (489 mg, 41%) as ﬂuorescent yellow oil. MS; m=z 292,

294 (M^þ, M^þþ 2, based on ⁷⁹Br) for C₁₀H₁₄BrNO₂S. IR; 2955,

1

2930, and 2860 (CH), 1509 and 1326 (NO₂). H NMR; 7.64 (1H,

s, Th–H), 2.57 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.65–1.20 (8H,

m, CH₂(CH₂)₄CH₃), 0.90 (3H, t, J ¼ 7 Hz, CH₃). UV–vis; 294

(4300), 346 (9600). Found: C, 40.83; H, 4.96; N, 4.85%. Calcd

for C₁₀H₁₄BrNO₂S: C, 41.09; H, 4.83; N, 4.79%.

Method B (transformation via oxime); a solution of 2-bromo-

5-formyl-3-hexylthiophene (2 g, 7.27 mmol) and hydroxylamine

5-Bromo-5⁰-cyano-3,3⁰-dihexyl-2,2⁰-bithiophene (9c).

9c

hydrochloride (NH₂OH HCl, 645 mg, 9.28 mmol) in pyridine–

was prepared by way of Method B, similar to 2-bromo-5-cyano-

3-hexylthiophene. The oximes 11 were separated to each isomer

by column chromatography on SiO₂with CHCl₃. Syn-oxime

(R_f¼ 0:14 with CHCl₃) of 11: Yield; 46%. Pale yellow semi-

solid. MS; m=z 456, 458 (M^þþ 1, M^þþ 3, based on ⁷⁹Br) for

C₂₁H₃₀BrNOS₂. IR; 3277 (br, OH), 2957, 2925, and 2870 (CH),

1631 (CNO), 1464 (NO). ¹H NMR; 8.20 (1H, s, HCNO), 7.64

(1H, s, OH), 7.23 (1H, s, Th–H), 7.05 (1H, s, Th–H), 2.52–2.44

(4H, m, CH₂(CH₂)₄CH₃), 1.52–1.22 (16H, m, CH₂(CH₂)₄CH₃),

0.88–0.83 (6H, m, CH₃). UV–vis; 308 (12880). Found: C, 54.96;

H, 6.73; N, 3.11%. Calcd for C₂₁H₃₀BrNOS₂: C, 55.24; H, 6.62;

N, 3.07%. Anti-oxime (R_f¼ 0:35 with CHCl₃) of 11: Yield; 52%.

Pale yellow semi-solid. MS; m=z 456, 458 (M^þþ 1, M^þþ 3,

based on ⁷⁹Br) for C₂₁H₃₀BrNOS₂. IR; 3600–2900 (very br, OH),

ꢆ

ethanol (Py–EtOH; 20 cm³, 1:1 v/v) was stirred under reﬂux over

12 h. The mixture was concentrated under reduced pressure, ad-

mixed with water and extracted with CHCl₃. The extracts were

shaken with dil. HCl, washed with brine and then dried. The res-

idue obtained after removal of the solvent was recrystallized from

CHCl₃–EtOH to aﬀord the oxime (2.04 g, 97%) as pale yellow

microcrystallines. The product should consist of syn- and anti-

oximes, but its equilibrium ratio was hard to be analyzed. Thus,

the characterization of the product was determined as an equilibri-

um mixture (also see below). Mp; 38–42 ^ꢃC. MS; m=z 290, 292

(M^þþ 1, M^þþ 3, based on ⁷⁹Br) for C₁₁H₁₆BrNOS. IR; 3066

(br, OH), 2952, 2926, and 2856 (CH), 1638 (CNO), 1462 (NO).

¹H NMR; 8.13 (1H, s, HCNO), 7.59 (1H, s, OH), 6.88 (1H, s,

Th–H), 2.57 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.65–1.20 (8H,

m, CH₂(CH₂)₄CH₃), 0.89 (3H, t, J ¼ 7 Hz, CH₃). UV–vis; 262

(8840), 273 (9860, sh), 295 (15110). Found: C, 45.28; H, 5.77; N,

4.65%. Calcd for C₁₁H₁₆BrNOS: C, 45.51; H, 5.56; N, 4.83%. The

oxime (1.90 g, 6.55 mmol) thus obtained was admixed with so-

dium acetate (20.3 mg, 0.25 mmol) in acetic anhydride (Ac₂O;

10 cm³) and was stirred under reﬂux over 3 h. The reaction mix-

ture was poured into dil. NaOH aq. and was extracted with CHCl₃.

The extracts were washed with brine and then dried. The residue

was puriﬁed in a similar way to Method A to aﬀord 2-bromo-5-

cyano-3-hexylthiophene (1.46 g, 82%).

1

2930, 2855, and 2870 (CH), 1649 (CNO), 1466 (NO). H NMR;

8.20 (1H, s, HCNO), 7.64 (1H, br s, OH), 7.23 (1H, s, Th–H),

7.05 (1H, s, Th–H), 2.48–2.42 (4H, m, CH₂(CH₂)₄CH₃), 1.51–

1.15 (16H, m, CH₂(CH₂)₄CH₃), 0.90–0.80 (6H, m, CH₃). UV–

vis; 301 (13500). Found: C, 55.01; H, 6.90; N, 2.88%. Calcd for

C₂₁H₃₀BrNOS₂: C, 55.24; H, 6.62; N, 3.07%. 9c: Yield; 62%

from the syn-oxime and 97% from the anti-oxime. Yellow

semi-solid. MS; m=z 438, 440 (M^þþ 1, M^þþ 3, based on ⁷⁹Br)

for C₂₁H₂₈BrNS₂. IR; 2955, 2927, and 2857 (CH), 2216 (CN).

¹H NMR; 7.47 (1H, s, Th–H), 6.96 (1H, s, Th–H), 2.49 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.43 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄-

CH₃), 1.55–1.20 (16H, m, CH₂(CH₂)₄CH₃), 0.88–0.85 (6H, m,

CH₃). UV–vis; 252 (13600), 275 (11200, sh), 329 (9150). Found:

C, 57.37; H, 6.66; N, 3.03%. Calcd for C₂₁H₂₈BrNS₂: C, 57.51; H,

6.44; N, 3.19%.

5-Bromo-5⁰-cyano-4,4⁰-dihexyl-2,2⁰-bithiophene (15c). 15c

was prepared by way of Method B, similar to 9c. Syn- and anti-

oximes 13 from 15d were distinguished from each other on

TLC (R_f¼ 0:12 and 0.38 with CHCl₃) but could not be separated

from each isomer. The extracts of the respective isomers from pre-

parative TLC with CHCl₃spontaneously changed, aﬀording the

same mixture of syn- and anti-oximes reproducibly. The ratio of

syn- and anti-oximes could not be ascertained because there were

no distinguishable peaks belonging to each isomer in ¹H NMR

spectrum. Thus, the characterization of the product was deter-

mined as an equilibrium mixture. Yield; total 89%. Pale yellow

semi-solid. MS; m=z 457, 459 (M^þþ 1, M^þþ 3, based on ⁷⁹Br)

for C₂₁H₃₀BrNOS₂. IR; 3170, 3065 and 3020 together with a

broad band at 3450–2750 (OH), 2952, 2926, and 2855 (CH),

1635 and 1618 (CNO), 1467 (br, NO). ¹H NMR; 8.29 (1H, s,

HCNO), 7.75 (1H, br s, OH), 6.88 (1H, s, Th–H), 6.86 (1H, s,

Th–H), 2.74–2.51 (4H, m, CH₂(CH₂)₄CH₃), 1.63–1.31 (16H, m,

CH₂(CH₂)₄CH₃), 0.90–0.88 (6H, m, CH₃). UV–vis; 257 (6800),

353 (15300), 377 (10750, sh). Found: C, 55.18; H, 6.83; N,

3.33%. Calcd for C₂₁H₃₀BrNOS₂: C, 55.24; H, 6.62; N, 3.07%.

15c: Yield; 97% from a mixture of syn- and anti-oximes. Yellow

semi-solid. MS; m=z 439, 441 (M^þþ 1, M^þþ 3, based on ⁷⁹Br)

for C₂₁H₂₈BrNS₂. IR; 2955, 2927, and 2857 (CH), 2216 (CN).

¹H NMR; 6.94 (1H, s, Th–H), 6.90 (1H, s, Th–H), 2.74 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.54 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄-

2-Bromo-5-formyl-3-hexylthiophene. To a solution of 2,5-

dibromo-3-hexylthiophene¹⁴(2.5 g, 7.67 mmol) in THF (25 cm³)

was added n-BuLi (1.6 M solution in hexane, 4.8 cm³, 7.68 mmol)

at ꢁ78 ^ꢃC over 15 min. After stirring for additional 20 min, DMF

(3.0 cm³, 38.8 mmol) was added dropwise at ꢁ78 ^ꢃC. The reaction

mixture was gradually warmed up to room temperature and then

poured into water and extracted with CHCl₃, successively. The

residue obtained after removal of the solvent was chromatograph-

ed on SiO₂(4:1 ꢅ 16 cm) with hexane to aﬀord 2-bromo-5-for-

myl-3-hexylthiophene (1.61 g, 76%) as pale yellow oil, together

with 2-bromo-3-hexylthiophene¹⁴(128 mg, 7%). 2-Bromo-5-for-

myl-3-hexylthiophene: MS; m=z 275, 277 (M^þ, M^þþ 2, based

on ⁷⁹Br) for C₁₁H₁₅BrOS. IR; 2955, 2978, and 2857 (CH), 1672

(CO). ¹H NMR; 9.76 (1H, s, CHO), 7.46 (1H, s, Th–H), 2.60 (2H,

t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.65–1.20 (8H, m, CH₂(CH₂)₄-

CH₃), 0.90 (3H, t, J ¼ 7 Hz, CH₃). UV–vis; 271 (9300), 309

(11700). Found: C, 48.06; H, 5.62%. Calcd for C₁₁H₁₅BrOS: C,

47.99; H, 5.49%.

2-Bromo-3-hexyl-5-nitrothiophene. To a solution of 2-bro-

mo-3-hexylthiophene (1.0 g, 4.05 mmol) in Ac₂O–THF (6 cm³,

2:1 v/v) was added a mixture of HNO₃(60% solution, 0.93 cm³,

12.2 mmol) and Ac₂O (3 cm³) at ꢁ40 ^ꢃC over 15 min under Ar

atmosphere, and the mixture was kept standing at 0 ^ꢃC for 12 h.

A solution of potassium hydroxide (KOH; 2 M solution in H₂O,

50 cm³) was added to the reaction mixture at 0 ^ꢃC, and then after

30 min stirring the mixture was extracted with CHCl₃. The ex-

tracts were washed with brine and dried. The residue obtained af-

ter removal of the solvent was chromatographed on SiO₂(3:2 ꢅ 8

cm) with hexane–CHCl₃to aﬀord 2-bromo-3-hexyl-5-nitrothio-

382 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

CH₃), 1.68–1.27 (16H, m, CH₂(CH₂)₄CH₃), 0.91–0.89 (6H, m,

CH₃). UV–vis; 265 (6500), 341 (14800). Found: C, 57.29; H,

6.40; N, 3.12%. Calcd for C₂₁H₂₈BrNS₂: C, 57.51; H, 6.44; N,

3.19%.

responding bromo derivatives (4–5 mmol), copper(I) iodide (CuI,

0.1–0.15 mmol) and dichlorobis(triphenylphosphine)palladium

(0.2–0.25 mmol) in diisopropylamine (15 cm³) was added TMSA

(equivalent to the bromo derivative) at room temperature under

Ar atmosphere. The mixture was stirred at room temperature for

3–5 h, by checking the reaction progress with TLC. The reaction

mixture was poured into water and extracted with CHCl₃. The

residue obtained after removal of the solvent was chromatograph-

ed on SiO₂(3:2 ꢅ 5{10 cm) with hexane–CHCl₃to aﬀord the

TMS-protected acetylene derivative. Successively, each solution

of the TMS-protected acetylene derivatives (3–5 mmol) in metha-

nol–hexane (10 cm³, 4:1 v/v) was stirred in the presence of anhy-

drous sodium carbonate (Na₂CO₃; 0.6–0.7 mmol) at room temper-

ature for 3–5 h. Poured into water, the mixture was extracted with

CHCl₃and the extracts were washed with brine. The residue

obtained after removal of the solvent was chromatographed on

Al₂O₃(3:2 ꢅ 5{10 cm) with hexane–CHCl₃to yield the desired

acetylene derivative, which was employed for the next coupling

reaction in a preparative purity grade. Thus, elemental analyses

of the terminal acetylenes 7, 12, and 16 were all abandoned.

5-Cyano-3-hexyl-2-(trimethylsilylethynyl)thiophene: Yield;

84%. Yellow oil. MS; m=z 289 (M^þ) for C₁₆H₂₃NSSi. IR; 2959,

2929, and 2859 (CH), 2216 (CN), 2148 (CꢇC). ¹H NMR; 7.33

(1H, s, Th–H), 2.66 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.65–1.20

(8H, m, CH₂(CH₂)₄CH₃), 0.90 (3H, t, J ¼ 7 Hz, CH₃), 0.26 (9H,

s, Si(CH₃)₃). UV–vis; 268 (4300), 279 (5600), 304 (8900), 316

(8900). Found: C, 66.12; H, 8.28; N, 4.62%. Calcd for C₁₆H₂₃-

NSSi: C, 66.38; H, 8.01; N, 4.84%. 7c: Yield; 64%. Yellow oil.

MS; m=z 217 (M^þ) for C₁₃H₁₅NS. IR; 3309 (CꢇCH), 2955,

2927 and 2857 (CH), 2217 (CN), 2110 (CꢇC). ¹H NMR; 7.36

(1H, s, Th–H), 3.58 (1H, s, CCH), 2.68 (2H, t, J ¼ 8 Hz, CH₂-

(CH₂)₄CH₃), 1.65–1.20 (8H, m, CH₂(CH₂)₄CH₃), 0.89 (3H, t, J ¼

7 Hz, CH₃). UV–vis; 293 (4.8, as relative intensity), 306 (14.8).

5-Formyl-3-hexyl-2-(trimethylsilylethynyl)thiophene: Yield,

82%. Yellow oil. MS; m=z 292 (M^þ) for C₁₆H₂₄OSSi. IR; 2958,

2928, and 2858 (CH), 2146 (CꢇC), 1673 (CO). ¹H NMR; 9.80

(1H, s, CHO), 7.50 (1H, s, Th–H), 2.69 (2H, t, J ¼ 8 Hz, CH₂-

(CH₂)₄CH₃), 1.70–1.20 (8H, m, CH₂(CH₂)₄CH₃), 0.89 (3H, t, J ¼

7 Hz, CH₃), 0.27 (9H, s, Si(CH₃)₃). UV–vis; 295 (6900), 338

(12300). Found: C, 65.48; H, 8.55%. Calcd for C₁₆H₂₄OSSi: C,

65.70; H, 8.27%. 7d: Yield; 94%. Yellow oil. MS; m=z 220 (M^þ)

for C₁₃H₁₆OS. IR; 3292 (CꢇCH), 2956, 2928, and 2858 (CH),

5-Bromo-5⁰-formyl-3,3⁰-dihexyl-2,2⁰-bithiophene (9d). To a

solution of 9b¹⁴(2 g, 4.06 mmol) in THF (20 cm³) was added n-

BuLi (1.6 M solution in hexane, 2.53 cm³, 4.05 mmol) dropwise

at ꢁ78 ^ꢃC over 15 min under Ar atmosphere and stirred for addi-

tional 20 min. To the resulting solution, DMF (1.57 cm³, 20.3

mmol) was added at ꢁ78 ^ꢃC and the mixture was gradually

warmed up to room temperature. Poured into water, the reaction

mixture was extracted with hexane. The extracts were washed

with brine and then dried. The residue obtained after removal of

the solvent was chromatographed on SiO₂(3:8 ꢅ 11 cm) with

hexane–CHCl₃to aﬀord 9d (1.03 g, 57%) as pale yellow oil. 9d:

MS; m=z 441, 443 (M^þþ 1, M^þþ 3, based on ⁷⁹Br) for C₂₁H₂₉-

BrOS₂. IR; 2955, 2927, and 2857 (CH), 1675 (CO). ¹H NMR;

9.86 (1H, s, CHO), 7.63 (1H, s, Th–H), 6.96 (1H, s, Th–H), 2.54

(2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.46 (2H, t, J ¼ 8 Hz, CH₂-

(CH₂)₄CH₃), 1.60–1.25 (16H, m, CH₂(CH₂)₄CH₃), 0.95–0.80

(6H, m, CH₃). UV–vis; 264 (12500), 329 (9800). Found: C,

56.84; H, 6.90%. Calcd for C₂₁H₂₉BrOS₂: C, 57.12; H, 6.62%.

5-Bromo-5⁰-formyl-4,4⁰-dihexyl-2,2⁰-bithiophene (15d). This

compound was prepared from 15b^8,14similar to 9d. 15d: Yield;

84%. Yellow oil. MS; m=z 441, 443 (M^þþ 1, M^þþ 3, based

on ⁷⁹Br) for C₂₁H₂₉BrOS₂. IR; 2955, 2927, and 2857 (CH),

1655 (CO). ¹H NMR; 9.98 (1H, s, CHO), 7.02 (1H, s, Th–H), 6.97

(1H, s, Th–H), 2.91 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.55 (2H,

t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.75–1.20 (16H, m, CH₂(CH₂)₄-

CH₃), 0.95–0.80 (6H, m, CH₃). UV–vis; 263 (8800), 371 (22900).

Found: C, 56.89; H, 6.48%. Calcd for C₂₁H₂₉BrOS₂: C, 57.12; H,

6.62%.

5-Bromo-3,3⁰-dihexyl-5⁰-nitro-2,2⁰-bithiophene (9e). To a

solution of 9a¹⁴(550 mg, 1.93 mmol) in Ac₂O (8 cm³) was added

a mixture of HNO₃(60% solution, 1 cm³, 9.5 mmol) and Ac₂O

(4 cm³) at ꢁ40 ^ꢃC over 15 min under Ar atmosphere, and the mix-

ture was kept standing at 0 ^ꢃC for 12 h. A solution of KOH (2 M

solution in H₂O, 60 cm³) was added to the reaction mixture at

0 ^ꢃC, and then after 30 min stirring the mixture was extracted with

CHCl₃. The extracts were washed with brine and dried. The resi-

due obtained after removal of the solvent was chromatographed

on SiO₂(3:2 ꢅ 8 cm) with hexane–CHCl₃to 9e (660 mg, quanti-

tative) as yellow oil. MS; m=z 457, 459 (M^þ, M^þþ 2, based

on ⁷⁹Br) for C₂₀H₂₈BrNO₂S₂. IR; 2955, 2928, and 2857 (CH),

1508 and 1334 (NO₂). ¹H NMR; 7.79 (1H, s, Th–H), 7.08 (1H,

s, Th–H), 2.50 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.47 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.57–1.21 (16H, m, CH₂(CH₂)₄CH₃),

0.88–0.84 (6H, m, CH₃). UV–vis; 271 (11300), 357 (14600).

Found: C, 52.08; H, 6.44; N, 2.88%. Calcd for C₂₀H₂₈BrNO₂S₂:

C, 52.38; H, 6.16; N, 3.06%.

1

2105 (CꢇC), 1675 (CO). H NMR; 9.83 (1H, s, CHO), 7.53 (1H,

s, Th–H), 3.67 (1H, s, CCH), 2.72 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄-

CH₃), 1.70–1.25 (8H, m, CH₂(CH₂)₄CH₃), 0.89 (3H, t, J ¼ 7 Hz,

CH₃). UV–vis; 290 (9.3, as relative intensity), 326 (11).

3-Hexyl-5-nitro-2-(trimethylsilylethynyl)thiophene: Yield;

80%. Yellow oil. MS; m=z 309 (M^þ) for C₁₅H₂₃NO₂SSi. IR;

2958, 2929, and 2858 (CH), 2148 (CꢇC), 1508 and 1331 (NO₂).

¹H NMR; 7.67 (1H, s, Th–H), 2.66 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄-

CH₃), 1.70–1.25 (8H, m, CH₂(CH₂)₄CH₃), 0.89 (3H, t, J ¼ 7 Hz,

CH₃), 0.27 (9H, s, Si(CH₃)₃). UV–vis; 313 (4900), 372 (13500).

Found: C, 57.99; H, 7.60; N, 4.26%. Calcd for C₁₅H₂₃NO₂SSi:

C, 58.21; H, 7.49; N, 4.53%. 7e: Yield; 76%. Yellow oil. MS; m=z

237 (M^þ) for C₁₂H₁₅NO₂S. IR; 3288 (CꢇCH), 2956, 2928, and

2859 (CH), 2105 (CꢇC), 1510 and 1333 (NO₂). ¹H NMR; 7.69

(1H, s, Th–H), 3.66 (1H, s, CCH), 2.68 (2H, t, J ¼ 8 Hz, CH₂-

(CH₂)₄CH₃), 1.70–1.25 (8H, m, CH₂(CH₂)₄CH₃), 0.89 (3H, t,

J ¼ 7 Hz, CH₃). UV–vis; 308 (7.4, as relative intensity), 357 (13).

5-Cyano-3,3⁰-dihexyl-5⁰-(trimethylsilylethynyl)-2,2⁰-bithio-

5-Bromo-4,4⁰-dihexyl-5⁰-nitro-2,2⁰-bithiophene (15e). This

compound was prepared from 15a^8,14similar to 9e. 15e: Yield;

55%. Yellow semi-solid. MS; m=z 457, 459 (M^þ, M^þþ 2, based

on ⁷⁹Br) for C₂₀H₂₈BrNO₂S₂. IR; 2952, 2927, and 2859 (CH),

1531 and 1318 (NO₂). ¹H NMR; 7.03 (1H, s, Th–H), 6.88 (1H,

s, Th–H), 3.02 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.56 (2H, t, J ¼

8 Hz, CH₂(CH₂)₄CH₃), 1.68–1.32 (6H, m, CH₂(CH₂)₄CH₃), 0.90

(6H, br t, J ¼ 7 Hz, CH₃). UV–vis; 277 (11000), 402 (22600).

Found: C, 52.11; H, 6.39; N, 2.79%. Calcd for C₂₀H₂₈NO₂S₂Br:

C, 52.38; H, 6.16; N, 3.06%.

General Preparative Procedures for the HTh–X and

DHBTh–X Acetylenes 12 and 16. To each solution of the cor-

phene:

M

Yield; 90%. Yellow oil. MS; m=z 455, 456 (M^þ,

^þþ 1) for C₂₆H₃₇NS₂Si. IR; 2957, 2928, and 2858 (CH), 2212

N. Hayashi et al.

Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

383

(CN), 2142 (CꢇC). ¹H NMR; 7.47 (1H, s, Th–H), 7.12 (1H, s, Th–

H), 2.49 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.43 (2H, t, J ¼ 8 Hz,

CH₂(CH₂)₄CH₃), 1.56–1.23 (16H, m, CH₂(CH₂)₄CH₃), 0.86 (6H,

br m, CH₃), 0.26 (9H, s, Si(CH₃)₃). UV–vis; 270 (7650, sh), 302

(12500). Found: C, 68.18; H, 8.43; N, 2.77%. Calcd for C₂₆H₃₇-

NS₂Si: C, 68.51; H, 8.18; N, 3.07%. Further trial for a satisfactory

analysis of this compound was given up. 12c: Yield; 75%. Yellow

semi-solid. MS; m=z 383, 384, 385 (M^þ, M^þþ 1, M^þþ 2) for

C₂₃H₂₉NS₂. IR; 3311 (CꢇCH), 2957, 2928, and 2858 (CH),

2215 (CN), 2135 (CꢇC). ¹H NMR; 7.48 (1H, s, Th–H), 7.16 (1H,

s, Th–H), 3.41 (1H, s, CCH), 2.50 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄-

CH₃), 2.44 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.54–1.18 (16H, m,

CH₂(CH₂)₄CH₃), 0.88–0.84 (6H, m, CH₃). UV–vis; 308 (5.7, as

relative intensity), 357 (10).

3,3⁰-Dihexyl-5-nitro-5⁰-(trimethylsilylethynyl)-2,2⁰-bithio-

phene: Yield, 98%. Yellow solid. MS; m=z 475, 476 (M^þ,

M

^þþ 1) for C₂₅H₃₇NO₂S₂Si. IR; 2957, 2928, and 2858 (CH),

2148 (CꢇC), 1508 and 1334 (NO₂). ¹H NMR; 7.79 (1H, s, Th–H),

7.12 (1H, s, Th–H), 2.50 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.47

(2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.53–1.23 (16H, m, CH₂-

(CH₂)₄CH₃), 0.90–0.84 (6H, m, CH₃), 0.25 (9H, s, Si(CH₃)₃).

UV–vis; 287 (18100), 368 (13600). Found: C, 63.01; H, 7.94;

N, 2.78%. Calcd for C₂₅H₃₇NO₂S₂Si: C, 63.11; H, 7.84; N,

2.94%. 12e: Yield, quantitative. Yellow solid. MS; m=z 403,

404 (M^þ, M^þþ 1) for C₂₂H₂₉NO₂S₂. IR; 3312 (CꢇCH), 2956,

2928, and 2858 (CH), 2125 (CꢇC), 1508 and 1335 (NO₂).

¹H NMR; 7.80 (1H, s, Th–H), 7.17 (1H, s, Th–H), 3.43 (1H,

s, CCH), 2.52–2.46 (4H, m, CH₂(CH₂)₄CH₃), 1.57–1.19 (16H,

m, CH₂(CH₂)₄CH₃), 0.88–0.85 (6H, m, CH₃). UV–vis; 280

(16800), 363 (12300).

5-Cyano-4,4⁰-dihexyl-5⁰-(trimethylsilylethynyl)-2,2⁰-bithio-

phene:

M

Yield; 95%. Yellow oil. MS; m=z 455, 456 (M^þ,

^þþ 1) for C₂₆H₃₇NS₂Si. IR; 2957, 2928, and 2858 (CH), 2216

4,4⁰-Dihexyl-5-nitro-5⁰-(trimethylsilylethynyl)-2,2⁰-bithio-

phene: Yield, 67%. Yellow oil. MS; m=z 475, 476 (M^þ, M^þþ 1)

for C₂₅H₃₇NO₂S₂Si. IR; 2956, 2929, and 2859 (CH), 2140 (CꢇC),

1543 and 1321 (NO₂). ¹H NMR; 7.07 (1H, s, Th–H), 6.92 (1H,

s, Th–H), 3.02 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.66 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.69–1.26 (16H, m, CH₂(CH₂)₄CH₃),

0.91–0.87 (6H, m, CH₃), 0.27 (9H, s, Si(CH₃)₃). UV–vis; 290

(8050), 416 (19400). Found: C, 63.00; H, 8.02; N, 2.76%. Calcd

for C₂₅H₃₇NO₂S₂Si. C, 63.11; H, 7.84; N, 2.94%. 16e: Yield,

95%. Yellow solid. MS; m=z 403, 404 (M^þ, M^þþ 1) for C₂₂H₂₉-

NO₂S₂. IR; 3308 (CꢇCH), 2956, 2929, and 2858 (CH), 2100

(CꢇC), 1531 and 1318 (NO₂). ¹H NMR; 7.09 (1H, s, Th–H), 6.94

(1H, s, Th–H), 3.58 (1H, s, CCH), 3.02 (2H, t, J ¼ 8 Hz, CH₂-

(CH₂)₄CH₃), 2.68 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.68–1.31

(16H, m, CH₂(CH₂)₄CH₃), 0.91–0.88 (6H, m, CH₃). UV–vis;

289 (7700), 410 (18500).

General Coupling Procedures for the Title Compounds 1–4.

To a solution of anhydrous Cu(OAc)₂(7–10 mmol, more than 10

times to the total amount of corresponding acetylenes) in Py–

MeOH (100 cm³, 5:1 v/v), a mixture of OEP acetylene 5 (0.1–

0.2 mmol) and DHBTh acetylene 12 or 16 (0.5–1.0 mmol, ca. 5

times to 5) in Py–MeOH (250 cm³, 5:1 v/v) was added at 40–

45 ^ꢃC over 12 h. The mixture was stirred at room temperature

for additional 12 h, by checking the reaction progress with TLC.

The reaction mixture was concentrated under reduced pressure

to ca. 30 cm³in volume, poured into water and extracted with

CHCl₃. The extracts were washed with dil. HCl, sat. NaHCO₃,

brine, and then dried. The residue obtained after removal of

the solvent was chromatographed on SiO₂(3:8 ꢅ 30 cm) with

hexane–CHCl₃to aﬀord the products 1–4, together with the di-

acetylene-group connected OEP, Bzn, HTh, and DHBTh dimers

17–21 (Chart 2),³⁴respectively. Among derivatives 1–4, the new

products are only shown.

1b: Yield; 77%. Reddish purple microcrystallines (hexane–

CHCl₃). Mp; >260 ^ꢃC. MS; m=z 793, 795 (M^þþ 1, M^þþ 3

based on ⁷⁹Br) for C₄₆H₄₇BrN₄Ni. IR; 2961, 2926, and 2866

(CH), 2200 and 2138 (CꢇC). ¹H NMR; 9.42 (2H, s, meso-H),

9.40 (1H, s, meso-H), 7.51 and 7.47 (2H each, d, J ¼ 13 Hz, Bzn–

H), 4.13 (4H, q, J ¼ 8 Hz, CH₂), 3.83–3.76 (12H, m, CH₂), 1.81–

1.71 (24H, m, CH₃). UV–vis; 410 (56600, sh), 435 (130800), 588

(14500), 610 (9650). Found: C, 69.34; H, 6.18; N, 6.86%. Calcd

for C₄₆H₄₇BrN₄Ni: C, 69.54; H, 5.96; N, 7.05%.

1c: Yield; 73%. Reddish purple microcrystallines (hexane–

CHCl₃). Mp; 255–260 ^ꢃC (dec). MS; m=z 739, 740 (M^þ, M^þþ

1) for C₄₇H₄₇N₅Ni. IR; 2965, 2930, and 2870 (CH), 2227 (CN),

2193 and 2136 (CꢇC). ¹H NMR; 9.43 (2H, s, meso-H), 9.41 (1H,

(CN), 2148 (CꢇC). ¹H NMR; 6.97 (1H, s, Th–H), 6.94 (1H, s, Th–

H), 2.77 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.68 (2H, t, J ¼ 8 Hz,

CH₂(CH₂)₄CH₃), 1.67–1.27 (16H, m, CH₂(CH₂)₄CH₃), 0.89–0.86

(6H, m, CH₃). UV–vis; 356 (17600), 385 (10500, sh). Found:

C, 68.33; H, 8.38; N, 2.83%. Calcd for C₂₆H₃₇NS₂Si. C, 68.51;

H, 8.18; N, 3.07%. 16c: Yield; 98%. Yellow needles (hexane–

CHCl₃). Mp; 88–91 ^ꢃC. MS; m=z 383, 384, 385 (M^þ, M^þþ 1,

M

^þþ 2) for C₂₃H₂₉NS₂. IR; (CꢇCH), 2956, 2929, and 2858

(CH), 2210 (CN), 2136 (CꢇC). ¹H NMR; 7.00 (1H, s, Th–H),

6.97 (1H, s, Th–H), 3.56 (1H, s, CCH), 2.74 (2H, t, J ¼ 8 Hz,

CH₂(CH₂)₄CH₃), 2.67 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.74–

1.28 (16H, m, CH₂(CH₂)₄CH₃), 0.92 (6H, br m, CH₃). UV–vis;

347 (14800), 378 (16600).

5-Formyl-3,3⁰-dihexyl-5⁰-(trimethylsilylethynyl)-2,2⁰-bithio-

phene: Yield, 78%. Yellow oil. MS; m=z 458 (M^þ) for C₂₆H₃₈-

OS₂Si. IR; 2957, 2928, and 2857 (CH), 2147 (CꢇC), 1676 (CO).

¹H NMR; 9.86 (1H, s, CHO), 7.63 (1H, s, Th–H), 7.13 (1H, s, Th–

H), 2.54 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.46 (2H, t, J ¼ 8 Hz,

CH₂(CH₂)₄CH₃), 1.60–1.15 (16H, m, CH₂(CH₂)₄CH₃), 0.95–0.80

(6H, m, CH₃), 0.25 (9H, s, Si(CH₃)₃). UV–vis; 273 (15100), 298

(13700), 341 (13600). Found: C, 67.85; H, 8.34%. Calcd for

C₂₆H₃₈OS₂Si. C, 68.06; H, 8.35%. 12d: Yield, 98%. Yellow oil.

MS; m=z 386, 387 (M^þ, M^þþ 1) for C₂₃H₃₀OS₂. IR; 3309

(CꢇCH), 2955, 2927, and 2857 (CH), 2133 (CꢇC), 1673 (CO).

¹H NMR; 9.87 (1H, s, CHO), 7.64 (1H, s, Th–H), 7.16 (1H, s,

Th–H), 3.41 (1H, s, CCH), 2.55 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄-

CH₃), 2.47 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.60–1.25 (16H,

m, CH₂(CH₂)₄CH₃), 0.90–0.75 (6H, m, CH₃). UV–vis; 270 (8.5,

as relative intensity), 334 (7.8).

5-Formyl-4,4⁰-dihexyl-5⁰-(trimethylsilylethynyl)-2,2⁰-bithio-

phene:

Yield, 66%. Yellow oil. MS; m=z 458 (M^þ) for

C₂₆H₃₈OS₂Si. IR; 2957, 2928, and 2857 (CH), 2141 (CꢇC),

1656 (CO). ¹H NMR; 9.98 (1H, s, CHO), 7.06 (1H, s, Th–H),

7.02 (1H, s, Th–H), 2.91 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃),

2.66 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.75–1.25 (16H, m,

CH₂(CH₂)₄CH₃), 0.90 (6H, t, J ¼ 7 Hz, CH₃), 0.26 (9H, s,

Si(CH₃)₃). UV–vis; 282 (8000), 388 (22400). Found: C, 67.79;

H, 8.47%. Calcd for C₂₆H₃₈OS₂Si: C, 68.06; H, 8.35%. 16d:

Yield, 95%. Yellow oil. MS; m=z 386, 387 (M^þ, M^þþ 1) for

C₂₃H₃₀OS₂. IR; 3308 (CꢇCH), 2955, 2927, and 2857 (CH), 2120

(CꢇC), 1652 (CO). ¹H NMR; 9.98 (1H, s, CHO), 7.08 (1H, s, Th–

H), 7.03 (1H, s, Th–H), 3.56 (1H, s, CCH), 2.91 (2H, t, J ¼ 8 Hz,

CH₂(CH₂)₄CH₃), 2.67 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.75–

1.20 (16H, m, CH₂(CH₂)₄CH₃), 0.89 (6H, t, J ¼ 7 Hz, CH₃). UV–

vis; 276 (1.0 as relative intensity), 379 (3.1).

384 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

s, meso-H), 7.69 and 7.67 (2H each, d, J ¼ 13 Hz, Bzn–H), 4.12

(4H, q, J ¼ 8 Hz, CH₂), 3.83–3.76 (12H, m, CH₂), 1.81–1.72

(24H, m, CH₃). UV–vis; 440 (108000, sh), 446 (127700), 565

(86500, sh), 587 (11500), 607 (12050), 615 (9650, sh). Found:

C, 76.12; H, 6.50; N, 9.46%. Calcd for C₄₇H₄₇N₅Ni: C, 76.22;

H, 6.40; N, 9.46%.

H, 7.18; N, 7.03%.

3d: Yield; 77%. Dark green microcrystallines (CHCl₃–

MeOH). Mp; >280 ^ꢃC. MS; m=z 1000, 1001 (M^þþ 1, M^þþ 2)

for C₆₁H₇₂N₄NiOS₂. IR; 2962, 2927, and 2868 (CH), 2181 and

2130 (CꢇC), 1671 (CO). ¹H NMR; 9.88 (1H, s, CHO), 9.42

(2H, s, meso-H), 9.40 (1H, s, meso-H), 7.65 (1H, s, Th–H), 7.31

(1H, s, Th–H), 4.12 (4H, q, J ¼ 8 Hz, CH₂CH₃), 3.85–3.70 (12H,

m, CH₂CH₃), 2.59 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.53 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.85–1.70 (24H, m, CH₂CH₃), 1.35–

1.20 (16H, m, CH₂(CH₂)₄CH₃), 0.90 (6H, m, CH₂(CH₂)₄CH₃).

UV–vis; 446 (100200), 560 (8800, sh), 588 (12900), 618 (10800,

sh). Found: C, 73.11; H, 7.48; N, 5.51%. Calcd for C₆₁H₇₂N₄-

NiOS₂: C, 73.26; H, 7.26; N, 5.60%.

1d: Yield; 66%. Reddish purple microcrystallines (hexane–

CHCl₃). Mp; 260–267 ^ꢃC (dec). MS; m=z 742, 743 (M^þ, M^þþ 1)

for C₄₇H₄₈N₄NiO. IR; 2963, 2930, and 2869 (CH), 2191 and 2136

1

(CꢇC), 1699 (CO), 1598 (C=C). H NMR; 10.05 (1H, s, CHO),

9.43 (2H, s, meso-H), 9.41 (1H, s, meso-H), 7.89 and 7.75 (2H

each, d, J ¼ 13 Hz, Bzn–H), 4.13 (4H, q, J ¼ 8 Hz, CH₂CH₃),

3.84–3.75 (12H, m, CH₂), 1.83–1.71 (24H, m, CH₃). UV–vis;

445 (117000, sh), 450 (135500), 570 (10700, sh), 596 (11800),

615 (11000, sh). Found: C, 75.68; H, 6.43; N, 7.18%. Calcd for

C₄₇H₄₈N₄NiO: C, 75.91; H, 6.51; N, 7.54%. Further trial for a

satisfactory analysis of this compound was given up.

3e:

Yield; 42%. Dark green microcrystallines (CHCl₃–

MeOH). Mp; >280 ^ꢃC. MS; m=z 1017, 1018 (M^þ, M^þþ 1) for

C₆₀H₇₁N₅NiO₂S₂. IR; 2964, 2930, and 2870 (CH), 2183 and

2133 (CꢇC), 1464 and 1329 (NO₂). ¹H NMR; 9.42 (2H, s,

meso-H), 9.40 (1H, s, meso-H), 7.82 (1H, s, Th–H), 7.30 (1H, s,

Th–H), 4.12 (4H, q, J ¼ 8 Hz, CH₂CH₃), 3.83–3.77 (12H, m,

CH₂CH₃), 2.56 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.54 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.81–1.72 (24H, m, CH₂CH₃), 1.28–

1.23 (16H, m, CH₂(CH₂)₄CH₃), 0.89–86 (6H, m, CH₂(CH₂)₄-

CH₃). UV–vis; 444 (101500), 565 (22000, sh), 590 (32000), 610

(23500, sh). Found: C, 70.48; H, 7.34; N, 6.79%. Calcd for

C₆₀H₇₁N₅NiO₂S₂: C, 70.85; H, 7.04; N, 6.89%. Further trial for

a satisfactory analysis of this compound was given up.

2c:

Yield; 43%. Dark green microcrystallines (CHCl₃–

MeOH). Mp; >280 ^ꢃC. MS; m=z 830, 831 (M^þþ 1, M^þþ 2)

for C₅₁H₅₇N₅SNi. IR; 2961, 2928, and 2869 (CH), 2209 (CN),

2181 and 2130 (CꢇC). ¹H NMR; 9.43 (2H, s, meso-H), 9.41

(1H, s, meso-H), 7.40 (1H, s, Th–H), 4.11 (4H, q, J ¼ 8 Hz, CH₂-

CH₃), 3.85–3.70 (12H, m, CH₂CH₃), 2.79 (2H, t, J ¼ 8 Hz, CH₂-

(CH₂)₄CH₃), 1.85–1.65 (24H, m, CH₂CH₃), 1.40–1.20 (8H, m,

CH₂(CH₂)₄CH₃), 0.90 (3H, t, J ¼ 7 Hz, CH₂(CH₂)₄CH₃). UV–

vis; 453 (94600), 580 (68000, sh), 595 (10700), 618 (9400, sh).

Found: C, 73.56; H, 6.78; N, 8.27%. Calcd for C₅₁H₅₇N₅NiS:

C, 73.73; H, 6.92; N, 8.43%.

4c:

Yield; 65%. Dark green microcrystallines (CHCl₃–

MeOH). Mp; 240–250 ^ꢃC (dec). MS; m=z 997, 998 (M^þ, M^þþ 1)

for C₆₁H₇₁N₅NiS₂. IR; 2962, 2929, and 2869 (CH), 2206 (CN),

2173 and 2126 (CꢇC). ¹H NMR; 9.42 (2H, s, meso-H), 9.39

(1H, s, meso-H), 7.07 (1H, s, Th–H), 7.01 (1H, s, Th–H), 4.12

(4H, q, J ¼ 8 Hz, CH₂CH₃), 3.84–3.70 (12H, m, CH₂CH₃), 2.83–

2.74 (4H, m, CH₂(CH₂)₄CH₃), 1.82–1.68 (24H, m, CH₂CH₃),

1.36–1.23 (8H, m, CH₂(CH₂)₄CH₃), 0.90 (6H, m, CH₂(CH₂)₄-

CH₃). UV–vis; 400 (23500, sh), 444 (100400, sh), 465

(132600), 565 (9450, sh), 593 (10800), 610 (8800, sh). Found:

C, 73.27; H, 7.47; N, 6.78%. Calcd for C₆₁H₇₁N₅NiS₂: C,

73.48; H, 7.18; N, 7.03%.

2d:

Yield; 27%. Dark green microcrystallines (CHCl₃–

MeOH). Mp; >280 ^ꢃC. MS; m=z 833, 834 (M^þþ 1, M^þþ 2)

for C₅₁H₅₈N₄NiOS. IR; 2964, 2929, and 2870 (CH), 2178 and

1

2130 (CꢇC), 1669 (CO). H NMR; 9.85 (1H, s, CHO), 9.43 (2H,

s, meso-H), 9.41 (1H, s, meso-H), 7.57 (1H, s, Th–H), 4.12 (4H, q,

J ¼ 8 Hz, CH₂CH₃), 3.85–3.70 (12H, m, CH₂CH₃), 2.82 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.85–1.70 (24H, m, CH₂CH₃), 1.45–

1.25 (8H, m, CH₂(CH₂)₄CH₃), 0.90 (3H, t, J ¼ 7 Hz, CH₂(CH₂)₄-

CH₃). UV–vis; 400 (36000, sh), 440 (76300), 462 (87200), 565

(63000, sh), 595 (14300), 610 (11500, sh). Found: C, 73.18; H,

7.24; N, 6.66%. Calcd for C₅₁H₅₈N₄NiOS: C, 73.46; H, 7.01; N,

6.72%.

4d:

Yield; 55%. Dark green microcrystallines (CHCl₃–

MeOH). Mp; >280 ^ꢃC. MS; m=z 1000, 1001 (M^þþ 1, M^þþ 2)

2e:

Yield; 11%. Dark green microcrystallines (CHCl₃–

for C₆₁H₇₂N₄NiOS₂. IR; 2962, 2928, and 2868 (CH), 2183 and

1

MeOH). Mp; >280 ^ꢃC. MS; m=z 850, 851 (M^þ, M^þþ 1) for

C₅₀H₅₇N₅NiO₂S. IR; 2959, 2928, and 2869 (CH), 2178 and 2130

(CꢇC), 1466 and 1319 (NO₂). ¹H NMR; 9.43 (2H, s, meso-H),

9.41 (1H, s, meso-H), 7.74 (1H, s, Th–H), 4.11 (4H, q, J ¼ 8 Hz,

CH₂CH₃), 3.85–3.70 (12H, m, CH₂CH₃), 2.79 (2H, t, J ¼ 8 Hz,

CH₂(CH₂)₄CH₃), 1.85–1.65 (24H, m, CH₂CH₃), 1.45–1.20 (8H,

m, CH₂(CH₂)₄CH₃), 0.90 (3H, t, J ¼ 7 Hz, CH₂(CH₂)₄CH₃). UV–

vis; 431 (70500), 479 (37200), 605 (17100). Found: C, 70.38; H,

6.98; N, 8.12%. Calcd for C₅₀H₅₇N₅ONiO₂S: C, 70.58; H, 6.75;

N, 8.23%.

2126 (CꢇC), 1652 (CO). H NMR; 9.99 (1H, s, CHO), 9.42 (2H,

s, meso-H), 9.40 (1H, s, meso-H), 7.13 (1H, s, Th–H), 7.05 (1H,

s, Th–H), 4.13 (4H, q, J ¼ 7 Hz, CH₂CH₃), 3.85–3.70 (12H, m,

CH₂CH₃), 2.91 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.78 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.85–1.65 (24H, m, CH₂CH₃), 1.45–

1.20 (16H, m, CH₂(CH₂)₄CH₃), 0.90–0.85 (6H, m, CH₂(CH₂)₄-

CH₃). UV–vis; 402 (26500, sh), 451 (89100), 471 (95000), 568

(17000, sh), 596 (20200). Found: C, 73.12; H, 7.47; N, 5.33%.

Calcd for C₆₁H₇₂N₄NiOS₂: C, 73.26; H, 7.26; N, 5.60%.

4e:

Yield; 57%. Dark green microcrystallines (CHCl₃–

3c:

Yield; 62%. Dark green microcrystallines (CHCl₃–

MeOH). Mp; >280 ^ꢃC. MS; m=z 1017, 1018 (M^þ, M^þþ 1) for

C₆₀H₇₁N₅NiO₂S₂. IR; 2963, 2929, and 2870 (CH), 2173 and

2128 (CꢇC), 1464 and 1315 (NO₂). ¹H NMR; 9.42 (2H, s,

meso-H), 9.40 (1H, s, meso-H), 7.15 (1H, s, Th–H), 6.98 (1H, s,

Th–H), 4.13 (4H, q, J ¼ 8 Hz, CH₂CH₃), 3.83–3.78 (12H, m,

CH₂CH₃), 3.03 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.79 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 1.81–1.66 (24H, m, CH₂CH₃), 1.43–

1.33 (16H, m, CH₂(CH₂)₄CH₃), 0.92–0.90 (6H, m, CH₂(CH₂)₄-

CH₃). UV–vis; 434 (771000, sh), 450 (78000), 493 (62600, sh),

599 (28000). Found: C, 70.58; H, 7.28; N, 6.64%. Calcd for

C₆₀H₇₁N₅NiO₂S₂: C, 70.85; H, 7.04; N, 6.89%.

MeOH). Mp; >280 ^ꢃC. MS; m=z 997, 998 (M^þ, M^þþ 1) for

C₆₁H₇₁N₅NiS₂. IR; 2962, 2928, and 2869 (CH), 2214 (CN),

2183 and 2131 (CꢇC). ¹H NMR; 9.43 (2H, s, meso-H), 9.41 (1H,

s, meso-H), 7.50 (1H, s, Th–H), 7.30 (1H, s, Th–H), 4.11 (4H, q,

J ¼ 8 Hz, CH₂CH₃), 3.88–3.77 (12H, m, CH₂CH₃), 2.54 (2H, t,

J ¼ 8 Hz, CH₂(CH₂)₄CH₃), 2.49 (2H, t, J ¼ 8 Hz, CH₂(CH₂)₄-

CH₃), 1.81–1.71 (24H, m, CH₂CH₃), 1.28–1.26 (8H, m, CH₂-

(CH₂)₄CH₃), 0.89–0.86 (6H, m, CH₂(CH₂)₄CH₃). UV–vis; 446

(110600), 567 (9700, sh), 586 (9900), 618 (9600, sh). Found: C,

73.29; H, 7.30; N, 6.83%. Calcd for C₆₁H₇₁N₅NiS₂: C, 73.48;

N. Hayashi et al.

Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

385

8

a) T. Wada, L. Wang, D. Fichou, H. Higuchi, J. Ojima, H.

Financial support by a Grant-in-Aid for Scientiﬁc and

Research from the Ministry of Education, Culture, Sports, Sci-

ence and Technology, is gratefully acknowledged. The present

work was ﬁnancially supported in part by The Hokuriku Indus-

trial Advancement Center (HIAC). HH also expresses his great

appreciation to VBL Research Center and Center of Instru-

mental Analyses, University of Toyama, for their supporting

measurements of the structural and physical properties of the

new compounds.

Sasabe, Mol. Cryst. Liq. Cryst. 1994, B255, 149. b) H. Higuchi, Y.

Uraki, H. Yokota, H. Koyama, J. Ojima, T. Wada, H. Sasabe, Bull.

Chem. Soc. Jpn. 1998 , 71 , 483.

9

a) H. Higuchi, T. Ishikura, K. Miyabayashi, M. Miyake, K.

Yamamoto, Tetrahedron Lett. 1999 , 40 , 9091. b) N. Hayashi, T.

Matsukihira, K. Miyabayashi, M. Miyake, H. Higuchi, Tetra-

hedron Lett. 2006 , 47 , 5585.

10 a) H. Higuchi, T. Ishikura, K. Mori, Y. Takayama, K.

Yamamoto, K. Tani, K. Miyabayashi, M. Miyake, Bull. Chem.

Soc. Jpn. 2001 , 74 , 889. b) N. Hayashi, A. Matsuda, E.

Chikamatsu, K. Mori, H. Higuchi, Tetrahedron Lett. 2003 , 44 ,

7155.

11 G. Eglington, A. R. Galbraith, Chem. Ind. 1956, 737.

12 K. Sonogashira, Y. Tohda, N. Hagihara, Tetrahedron Lett.

1975 , 16 , 4467.

13 S. Gronowitz, Thiophene and Its Derivatives, John Wiley

and Sons, New York, 1992.

References

#

This paper is dedicated to Emeritus Professor Philip Eaton

on the occasion of his 70th birth year.

A part of this work was preliminarily reported: H. Imahori,

1

H. Higuchi, Y. Matsuda, A. Itagaki, Y. Sakai, J. Ojima, Y. Sakata,

Bull. Chem. Soc. Jpn. 1994 , 67 , 2500.

2

A part of this work was preliminarily reported: N. Hayashi,

H. Nakashima, Y. Takayama, H. Higuchi, Tetrahedron Lett. 2003 ,

44 , 5423.

14 a) H. Higuchi, T. Nakayama, H. Koyama, J. Ojima, T.

Wada, H. Sasabe, Bull. Chem. Soc. Jpn. 1995 , 68 , 2363. b) H.

Higuchi, H. Koyama, N. Hayashi, J. Ojima, T. Wada, H. Sasabe,

Nonlinear Opt. 1996, 15, 209.

15 J. Nakayama, T. Fujimori, Sulfur Lett. 1990, 11, 29.

16 R. M. Kellogg, A. P. Schaap, E. T. Harper, H. Wynberg,

J. Org. Chem. 1968, 33, 2902.

17 M. F. Browne, R. L. Shriner, J. Org. Chem. 1957 , 22 ,

1320.

18 N. Hayashi, A. Naoe, K. Miyabayashi, M. Miyake, H.

Higuchi, Tetrahedron Lett. 2005 , 46 , 6961.

3

Only a few articles are shown. a) G. B. Kistiakowsky,

J. R. Ruhoﬀ, H. A. Smith, W. E. Vaughan, J. Am. Chem. Soc.

1936 , 58 , 146; M. J. S. Dewar, Pure Appl. Chem. 1975, 44,

767. b) S. B. Bulgarevich, V. S. Bolotnikov, V. N. Scheinker,

O. A. Osipov, A. D. Garnovskii, Zh. Org. Khim. 1976, 12, 197;

S. B. Bulgarrevich, T. A. Yusman, O. A. Osipov, Zh. Obshch.

Khim. 1984, 54, 1603. c) M. J. S. Dewar, The Molecular Orbital

Theory of Organic Chemistry, McGraw-Hill, New York, 1969;

J. I. Aihara, J. Am. Chem. Soc. 1976 , 98 , 6840. d) I. Gutman,

M. Milun, N. Trinajstic, J. Am. Chem. Soc. 1977 , 99 , 1692.

19 P. L. Corio, B. P. Dailey, J. Am. Chem. Soc. 1956 , 78 ,

3043.

4

Only a few articles are shown. a) D. I. Schuster, P. Cheng,

P. D. Jarowski, D. M. Guldi, C. P. Luo, L. Echegoyen, S. Pyo,

A. R. Holzwarth, S. E. Braslavsky, R. M. Williams, G. Klihm,

J. Am. Chem. Soc. 2004 , 126 , 7257. b) K. Tomizaki, A. B.

Lysenko, M. Taniguchi, J. S. Lindsey, Tetrahedron 2004 , 60 ,

2011. c) T. Nakamura, J. Ikemoto, M. Fujitsuka, Y. Araki, O.

Ito, K. Takimiya, Y. Aso, T. Otsubo, J. Phys. Chem. B 2005 ,

109 , 14365. d) M. J. Hodgson, V. V. Borovkov, Y. Inoue, D. P.

Arnold, J. Organomet. Chem. 2006 , 691 , 2162. e) K. M. Kadish,

L. Fremond, F. Burdet, L.-M. Barbe, C. P. Gros, R. Guilard,

J. Inorg. Biochem. 2006 , 100 , 858. f) F. Hauke, S. Atalick,

D. M. Guldi, A. Hirsh, Tetrahedron 2006 , 62 , 1923.

20 a) S. Gronowitz, R. A. Hoﬀman, Ark. Kemi 1961, 16, 539.

b) T. J. Batterham, in NMR Spectra of Simple Heterocycles, ed. by

E. C. Taylor, A. Weissberger, John Wiley Sons, New York, 1973,

p. 423.

21 a) J. A. Pople, Proc. R. Soc. London, Ser. A 1957, 239, 541.

b) J. S. Waugh, R. W. Fessenden, J. Am. Chem. Soc. 1957 , 79 ,

846.

22 J. Kao, L. Radom, J. Am. Chem. Soc. 1979 , 101 , 311.

23 N. Hayashi, M. Murayama, K. Mori, A. Matsuda, E.

Chikamatsu, K. Tani, K. Miyabayashi, M. Miyake, H. Higuchi,

Tetrahedron 2004 , 60 , 6363.

5

a) T. Sugiyama, T. Wada, H. Sasabe, Synth. Met. 1989 , 28 ,

24 J. W. Buchler, L. Puppe, Liebigs Ann. Chem. 1970, 142.

25 H. Imahori, Y. Tanaka, T. Okada, Y. Sakata, Chem. Lett.

1993 , 1215.

26 W. T. Simpson, J. Chem. Phys. 1949 , 17 , 1218.

27 H. Higuchi, H. Koyama, H. Yokota, J. Ojima, Tetrahedron

Lett. 1996 , 37 , 1617.

323. b) H. Okawa, H. Hattori, A. Yanase, Y. Kobayashi, A. Carter,

M. Sekiya, A. Kaneko, T. Wada, A. Yamada, H. Sasabe, Mol.

Cryst. Liq. Cryst. 1992, B3, 169. c) N. Hayashi, H. Nishi, K.

Morizumi, I. Kobayashi, H. Sakai, R. Akaike, K. Tani, H.

Higuchi, Recent Res. Dev. Org. Chem. 2004, 8, 401.

6

a) J. Casado, L. L. Miller, K. R. Mann, T. M. Pappenfus, H.

28 C. N. R. Rao, Chem. Ind. 1957, 1239.

29 K. K. Baldridge, M. S. Gordon, J. Am. Chem. Soc. 1988 ,

110 , 4204.

30 J. Deisenhofer, O. Epp, K. Miki, R. Huber, H. Michel,

J. Mol. Biol. 1984 , 180 , 385.

Higuchi, E. Orti, B. Milian, R. Pou-Amerigo, V. Hernandez, J. T.

Lopez Navarrete, J. Am. Chem. Soc. 2002 , 124 , 12380. b) D. E.

Janzen, M. W. Burand, P. C. Ewbank, T. M. Pappenfus, H.

´

Higuchi, D. A. da Silva Filho, V. G. Young, J.-L. Bredas, K. R.

Mann, J. Am. Chem. Soc. 2004 , 126 , 15295.

7

31 H. Higuchi, K. Shimizu, M. Takeuchi, J. Ojima, K.

Sugiura, Y. Sakata, Bull. Chem. Soc. Jpn. 1997 , 70 , 1923.

32 a) J.-H. Fuhrhop, in Porphyrins and Metalloporphyrins, ed.

K. M. Smith, Elsevier Scientiﬁc Publishing Co., Netherlands,

1975, p. 593. b) M. Gouterman, in The Porphyrins, ed. by D.

Dolphin, Academic Press, New York, 1978, Vol. III, p. 1. c) G.

Loew, in Inorganic Electronic Structure and Spectroscopy, ed.

by E. I. Solomon, A. B. P. Lever, John Wiley & Sons, Inc.,

New York, 1999, Vol. II, p. 451.

a) F. Forster, in Organic Chemistry, A Series of Mono-

graphs, ed. by A. T. Blomquist, Academic Press, New York,

1969, Vol. 15, p. 33. b) A. M. Moran, M. B. Desce, A. M. Kelley,

Chem. Phys. Lett. 2002, 358, 320. c) U. Lawrentz, W. Grahn, K.

Lukasznk, C. Klein, R. Wortmann, A. Feldner, D. Scherer, Chem.

Eur. J. 2002 , 8 , 1573. d) A. C. Benniston, A. Harriman, P. Li,

P. V. Patel, C. A. Sams, J. Org. Chem. 2006 , 71 , 3481, and many

other references cited therein.

386 Bull. Chem. Soc. Jpn. Vol. 80, No. 2 (2007)

Properties of OEP–Bzn–, –HTh–, and –DHBTh–X

33 a) H. Higuchi, S. Yoshida, Y. Uraki, J. Ojima, Bull. Chem.

now underway. The synthetic success of 26 should enable us dis-

cuss conclusively about the substituent eﬀect on not only oxida-

tion potentials but also reduction potentials of the OEP deriva-

tives. The substituent eﬀect on the electronic properties of all

the OEP derivatives including 26 will be reported continuously,

as compared with the orientation eﬀect of DHBTh.

´

Soc. Jpn. 1998 , 71 , 2229. b) V. Hernandez, S. Calvo Losada, J.

Casado, H. Higuchi, J. T. Lopez Navarrete, J. Phys. Chem. A

´

2000 , 104 , 661.

34 The synthetic strategy shown in the present work is not

suitable for the synthesis of the derivatives 26 with TH orientation

of DHBTh. Thus, the study to ﬁnd new synthetic strategy for 26 is

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