pellets using a Perkin-Elmer 1600 FT-IR. UV-Vis spectra
were recorded using a Perkin-Elmer Lambda 2 spectropho-
tometer. 1H NMR spectra (270 MHz) were recorded using a
JEOL GX-270 NMR spectrometer and are referenced to
2-(4-Methoxyphenyl)-5-(4-methoxynaphthyl)thiophene
(Me L5). To a solution of 1-methoxy-4-(2-thienyl)naphthalene
2
(0.35 g, 1.5 mmol) in thf (15 cm3) at 0 ¡C under N was added
2
dropwise n-BuLi (1.5 mmol; 0.9 cm3 of a 1.6 M solution in
internal SiMe . Electrochemical measurements were recorded
hexane). The mixture was stirred at 0 ¡C for 1 h and then
added to a solution of dry zinc(II) bromide (0.33 g, 1.5 mmol)
in thf (5 cm3) at 0 ¡C. This mixture was stirred at room tem-
perature for 1 h, and then added to a solution of 4-iodoanisole
(0.35 g, 1.3 mmol) and [PdCl (PPh ) ] (0.045 g, 0.06 mmol) in
4
on an EG&G/PAR model 273 potentiostat using a standard
three-electrode conÐguration consisting of Pt bead working
and auxiliary electrodes and a silver wire pseudo-reference
electrode; all measurements were calibrated against internal
ferrocene, and potentials are quoted against the ferrocene/
ferrocenium couple (Fc/Fc`). Solutions for electrochemical
studies in dry CH Cl contained 0.1 M [NBun ]PF as base
2
3 2
thf (20 cm3). After stirring for 2.5 h, the solvent was removed
using a rotary evaporator and the residue puriÐed by column
chromatography on silica eluting with a 1 : 5 diethyl etherÈ
2
2
4
6
electrolyte, and were ca.
1
mM in analyte. Spectro-
hexane mixture, to give 0.32 g (70%) of Me L5. EI MS: m/z
2
electrochemical measurements were performed at 243 K in a
home-built OTTLE cell using a Perkin-Elmer Lambda 19
spectrophotometer, as previously described.14
346 (M`, 100%), 331 ([MÈMe]`, 80%). 1H NMR (270 MHz,
CDCl ): d 3.84 (3 H, s, MeOC H ), 4.03 (3 H, s; MeOC H ),
3
6
4
10 6
6.84 (1 H, d, J \ 8; naphthyl), 6.93 (2 H, d, J \ 9 Hz; phenyl),
7.12 (1 H, d, J \ 4; naphthyl), 7.25 (1 H, d, J \ 4 Hz;
naphthyl), 7.49È7.60 (5 H, m; aromatic CH), 8.25È8.35 (2H, m,
aromatic CH).
Syntheses of ligands
2-(4-Hydroxyphenyl)-5-(4-hydroxynaphthyl)thiophene
4-Hydroxy-1-[4-(methoxyphenyl)azo]napthalene (HL3). 4-
Methoxyaniline (0.89 g, 7.2 mmol) was added to a solution of
conc. hydrochloric acid (2.6 cm3) in water (2.6 cm3) and then
cooled to 0 ¡C in a salt/ice bath. A solution of sodium nitrite
(0.54 g, 7.8 mmol) in water (3 cm3) was then added slowly with
stirring ensuring the temperature did not rise above 5 ¡C. In a
separate Ñask, 1-naphthol (1.4 g, 9.7 mmol) was dissolved in a
solution of sodium hydroxide (1.6 g) in water (10 cm3) and the
mixture cooled in an ice bath. To this was slowly added the
diazonium salt with stirring. After stirring for 15 min, conc.
hydrochloric acid (5 cm3) was added. The crude product was
then collected by Ðltration and puriÐed by silica column chro-
matography eluting with a 1 : 1 hexaneÈdiethyl ether mixture.
Yield was 0.99 g (49% based on 4-methoxyaniline). EI MS:
m/z 278 (M`, 100%), 143 ([HOC H ]`, 90%). 1H NMR (270
(H L5). A mixture of pyridine (10 cm3) and conc. hydrochloric
2
acid (10 cm3) was stirred together in an open Ñask under a
steady Ñow of nitrogen at 200 ¡C for 1 h. As soon as solid
pyridinium chloride started to sublime around the neck of the
Ñask, Me L5 (0.20 g, 0.58 mmol) was added and the mixture
2
stirred under N at 200 ¡C for 2 h. After cooling to room tem-
2
perature, water (50 cm3) was added and the resulting precipi-
tate was collected by Ðltration. The collected solid was then
puriÐed by Ñash column chromatography on silica eluting
with ethyl acetateÈhexane (1 : 4) to give pure H L5 as pale
2
yellow microcrystals (97 mg, 53%). EI MS: m/z 318 (M`,
100%). 1H NMR (270 MHz, (CD ) CO): d 6.92 (2H, d, J \ 9
3 2
Hz; C H ), 7.03 (1H, d, J \ 5 Hz; C H ), 7.14 (1H, d, J \ 4
6
4
10 6
Hz; C H ), 7.33È7.59 (6H, m, Ar), 8.23È8.37 (2H, m, Ar).
10
6
10
6
MHz, (CD ) CO): d 3.92 (3H, s; Me), 7.06 (1H, d, J \ 8;
2,5-Bis(4-methoxynaphthyl)thiophene (Me L6). 2,5-Bis(tri-
3 2
2
naphthyl), 7.14 (2H, d, J \ 8; phenyl), 7.57È7.72 (2H, m;
n-butylstannyl)thiophene (1.16 g, 1.75 mmol) and 1-methoxy-
napthyl), 7.88 (1H, d, J \ 8; naphthyl), 8.01 (2H, d, J \ 10;
phenyl), 8.34 (1H, d, J \ 8; naphthyl), 8.99 (1H, d, J \ 10 Hz,
naphthyl), 9.76 (1H, br s, OH).
4-iodonaphthalene (1.0 g, 3.52 mmol) were dissolved in tetra-
hydrofuran (20 cm3). [PdCl (PPh ) ] (0.125 g, 0.178 mmol)
2
3 2
was added and the mixture was then stirred at reÑux for 20 h.
After cooling to room temperature, the solvent was removed
in vacuo and the residue puriÐed by column chromatography
on silica eluting with hexane. Removal of the solvent a†orded
4-Hydroxy-1-[4-(hydroxyphenyl)azo]naphthalene
(H L4).
2
Using the same procedure as above, 4-aminophenol (1.0 g, 9.2
mmol) and 1-naphthol (1.4 g, 9.9 mmol) gave 1.5 g (60%) of
the desired product. EI MS: m/z 264 (M`, 75%), 143
([HOC H ]`, 100%). 1H NMR (270 MHz, (CD ) CO): d
Me L6 as a pale yellow powder (0.33 g, 47%). EI MS: m/z 396
2
(M`, 100%), 381 ([M [ Me]`, 70%), 366 ([M [ 2Me]`,
30%). 1H NMR (270 MHz, CDCl ): d 4.06 (6H, s; Me), 6.88
10
6
3 2
3
7.04 (3H, m; phenyl and naphthyl), 7.56È7.71 (2H, m;
naphthyl), 7.85 (1H, d, J \ 8; naphthyl), 7.94 (2H, d, J \ 9;
phenyl), 8.33 (1H, d, J \ 9; naphthyl), 8.98 (1H, d, J \ 8 Hz;
naphthyl), 9.02 (1H, br s, HOC H ), 9.93 (1H, br s,
(2H, d, J \ 8 Hz; naphthyl), 7.24 (2H, s; thienyl), 7.52È7.61
(6H, m; naphthyl), 8.36 (4H, m; naphthyl).
2,5-Bis(4-hydroxynaphthyl)thiophene (H L6). This was pre-
6
4
2
HOC H ).
pared by demethylation of Me L6 using exactly the same pro-
10
6
2
cedure as described above for H L5. From 160 mg of 1,4-
2
MeOC H (2-C H S)-1,4-C H OMe, yield was 100 mg
1-Methoxy-4-(2-thienyl)naphthalene. Thiophene (0.40 g, 4.8
mmol) was dissolved in tetrahydrofuran (25 cm3) and cooled
to [40 ¡C (dry ice/acetonitrile bath), and n-BuLi (4.8 mmol;
3.0 cm3 of a 1.6 M solution in hexane) was added dropwise.
The mixture was stirred at [40 ¡C for 45 min and then added
to a solution of dry zinc(II) bromide (1.07 g, 4.8 mmol) in tetra-
hydrofuran (15 cm3) at 0 ¡C. This mixture was stirred at 0 ¡C
for 1 h and then added to a solution of 1-methoxy-4-iodo-
naphthalene (1.0 g, 3.5 mmol) and [PdCl (PPh ) ] (0.145 g,
10
6
4
4
10 6
(68%). EI MS: m/z 368 (M`, 100%). 1H NMR (270 MHz,
(CD ) CO): d 7.02 (2H, d, J \ 8 Hz; naphthyl), 7.29 (2H, s;
3 2
thienyl), 7.51È7.63 (6H, m; naphthyl), 8.32È8.38 (4H, m;
naphthyl), 9.36 (2H, br s; OH).
Syntheses of complexes
All complexes were prepared by the same general method. A
typical example is given below.
2
3 2
0.21 mmol) in tetrahydrofuran (30 cm3) at room temperature.
After stirring for 2.5 h at room temperature, the solvent was
removed using a rotary evaporator and the residue puriÐed by
Synthesis of 1. A mixture of 1-naphthol (60 mg, 0.42 mmol)
and triethylamine (0.5 cm3) was stirred in toluene (10 cm3) for
column chromatography on silica eluting with
a
1 : 4
10 min at reÑux. [Mo(Tp*)(O)Cl ] (0.15 g, 0.31 mmol) was
2
dichloromethaneÈhexane mixture. The second band was col-
lected and yielded 0.70 g (83% yield) of 1-methoxy-4-(2-
thienyl)naphthalene. Spectroscopic data agree with those
reported previously.19
added and the mixture was then stirred at reÑux for a further
2 h. The solvent was then removed using a rotary evaporator
and the residue puriÐed by column chromatography on silica
eluting with 1 : 1 dichloromethaneÈhexane. Yield was 110 mg
1242
New J. Chem., 2001, 25, 1236È1243