Molybdenum complexes containing substituted cyclopenta[l]phenanthrenyl ligand

Article abstract of DOI:10.1016/j.jorganchem.2009.11.043

The synthesis of new cyclopenta[l]phenanthrenyl complexes [(η⁵-C₁₇H₁₀Me)(η³-C₃H₅)Mo(CO)₂] and [(η⁵-C₁₇H₉(COOMe)N(CH₂)₄)(η³-C₃H₅)Mo(CO)₂] is described. Although these compounds are structural analogues their reactivity is different. Protonation of [(η⁵-C₁₇H₁₀Me)(η³-C₃H₅)Mo(CO)₂] gives a stable ionic compound [(η⁵-C₁₇H₁₀Me)Mo(CO)₂(NCMe)₂][BF₄] while its analogue containing both tertiary amino and carboxylic ester groups [(η⁵-C₁₇H₉(COOMe)N(CH₂)₄)(η³-C₃H₅)Mo(CO)₂] decomposes under the same conditions. [(η⁵-C₁₇H₁₀Me)Mo(CO)₂(NCMe)₂][BF₄] reacts with cyclopentadiene to give a stable η⁴-complex [(η⁴-C₅H₆)(η⁵-C₁₇H₁₀Me)Mo(CO)₂][BF₄] that was successfully oxidized to the Mo(IV) dicationic compound [(η⁵-C₅H₅)(η⁵-C₁₇H₁₀Me)Mo(CO)₂][Br][BF₄].

Full text of DOI:10.1016/j.jorganchem.2009.11.043

Journal of Organometallic Chemistry 695 (2010) 680–686
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Molybdenum complexes containing substituted cyclopenta[l]phenanthrenyl ligand
a,b,
c
c
a,
*
*
ˇ
Jan Honzícek
, Abhik Mukhopadhyay , Cecilia Bonifacio , Carlos C. Romão
a Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal
b Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, nám. Studentská 573, 532 10 Pardubice, Czech Republic
c REQUIMTE/CQFB, Departamento de Química, FCT-UNL, 2829-516 Monte de Caparica, Portugal
a r t i c l e i n f o
a b s t r a c t
The synthesis of new cyclopenta[l]phenanthrenyl complexes [(g g
5-C17H10Me)( 3-C3H5)Mo(CO)2] and
Article history:
Received 2 October 2009
Received in revised form 23 November 2009
Accepted 27 November 2009
Available online 4 December 2009
[(
analogues their reactivity is different. Protonation of [(
ionic compound [(
5-C17H10Me)Mo(CO)2(NCMe)2][BF4] while its analogue containing both tertiary
amino and carboxylic ester groups [(
5-C17H9(COOMe)N(CH2)4)( 3-C3H5)Mo(CO)2] decomposes under
the same conditions. [(
5-C17H10Me)Mo(CO)2(NCMe)2][BF4] reacts with cyclopentadiene to give a stable
4-complex [( 4-C5H6)( 5-C17H10Me)Mo(CO)2][BF4] that was successfully oxidized to the Mo(IV) dicat-
ionic compound [(
5-C5H5)( 5-C17H10Me)Mo(CO)2][Br][BF4].
g g
5-C17H9(COOMe)N(CH2)4)( 3-C3H5)Mo(CO)2] is described. Although these compounds are structural
g
5-C17H10Me)( 3-C3H5)Mo(CO)2] gives a stable
g
g
g
g
g
Keywords:
Metallocene
Indenyl complexes
Molybdenum
X-ray diffraction
g
g
g
g
g
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
low temperature procedures was developed for unsubstituted
cyclopentadienyl complex [CpMo(
3-C3H5)(CO)2]. It is available
through reaction of [(
3-C3H5)Mo(CO)2(NCMe)2Cl] with an excess
g
There is currently considerable interest in the
p
-allyl complexes
5-C5H5). They
g
[Cp0Mo(g3-C3H5)(CO)2] (Cp0 = substituted Cp; Cp =
g
cyclopentadiene and NEt3 [1]. Amino acid derivatives were
serve as effective precursors for the synthesis of molybdenocenes
synthesized using another synthetic strategy. Lithiation of
substituted in one cyclopentadienyl ring [CpCp0MoL2]n+ [1–5].
[CpMo(
water work up a compound with a carboxylic acid group in the
cyclopentadienyl ring [(
5-C5H4COOH)Mo( 3-C3H5)(CO)2]. This
g
3-C3H5)(CO)2] followed by a treatment with CO2 gives after
Protonation of [Cp0Mo( 3-C3H5)(CO)2] with HBF4 followed by
g
cyclopentadiene coordination and oxidation gives dicationic com-
g
g
plexes [CpCp0Mo(CO)2]2+ [1,2].
compound serves as the effective precursor for a variety of amino
acid substituted cyclopentadienyl molybdenum compounds [13].
The aim of this work is to describe synthesis and reactivity
of new molybdenum complexes containing a substituted cyclo-
penta[l]phenanthrenyl (dibenzo[e,g]indenyl) ligand.
Several routes have been developed for the synthesis of
[CpMo(
decarbonylation of
The indenyl analogues [CpMo(
5-C9Me7) undergo g1 g3 allyl ligand rearrangement spontane-
ously without necessity of UV irradiation [7,8]. A more convenient
route giving [CpMo(
3-C3H5)(CO)2] starts from the allyl complex
[(
3-C3H5)Mo(CO)2(NCMe)2X] (X = Cl or Br) and the lithium
cyclopentadienide. It gives the product in 70–80% yield [1,9] and
was extended for compounds with indenyl (
5-C9H7) [10], fluore-
nyl (
5-C13H9) [1], dibenzo[c,g]fluorenyl ( 5-C21H13) [11] and
cyclopentadienyl ligands substituted with trimethylsilyl groups
5-C5H4SiMe3, 5-C5H3(SiMe3)2) [2,12] and carboxylic ester func-
tion (
5-C5H4COOMe) [2]. An alternative route avoiding LiCp and
g
3-C3H5)(CO)2]. The original one is based on photochemical
r
-allyl compound [CpMo(
g
1-C3H5)(CO)3] [6].
5-C9H7,
g
1-C3H5)(CO)3] (Cp0 =
g
g
–
2. Results and discussion
g
g
2.1. Synthesis of the substituted cyclopenta[l]phenanthrenes
g
Cyclopenta[l]phenanthrenes 3 and 6 were prepared according
to Scheme 1. Synthesis of starting ketones 2 and 4 was done using
a modified protocol [14]. Hydroxy-derivative 1 is available through
condensation of 9,10-phenanthrenequinone and methyl acetoace-
tate as was previously described for the ethyl ester analogue (1a)
[15]. The reaction of the compound 1 with hydriodic acid produces
compound 2 in high yield (90%). Here described methyl ester (2)
seems to be more stable toward acid hydrolysis than the ethyl
analogue (2a) because 1a gives a product of decarboxylation 4
under the same conditions [15]. The synthesis of the ketone 4
was optimized. It is given by a reaction of compound 2 with triflu-
oroacetic acid (tfa) in high yield (86%).
g
g
(g
g
g
* Corresponding authors. Address: Department of General and Inorganic Chem-
istry, Faculty of Chemical Technology, University of Pardubice, nám. Studentská
ˇ
573, 532 10 Pardubice, Czech Republic (J. Honzícek). Fax: +351 21 441 12 77 (C.C.
ˇ
Romão), fax: +420 46603 7068 (J. Honzícek).
E-mail addresses: jan.honzicek@upce.cz (J. Honzícek), ccr@itqb.unl.pt (C.C.
Romão).
ˇ
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.11.043

ˇ
J. Honzícek et al. / Journal of Organometallic Chemistry 695 (2010) 680–686
681
Scheme 1. Synthesis of substituted cyclopenta[l]phenanthrenes 3 and 6.
Condensation of compound 2 with pyrrolidine gives cyclo-
penta[l]phenanthrene substituted with both methoxycarbonyl
and tert amino functions (3). 2-Methyl-1H-cyclopenta[l]phenan-
threne (6) was prepared from compound 4 in line with the previ-
ously described procedure [16].
that were assigned to the phenanthrene protons. Multiplets of
the pyrrolidine CH2 groups were observed at 3.49–3.29 ppm and
2.06–1.97 ppm. Protons of the methoxycarbonyl group appear at
3.64 ppm (3a) and 3.95 ppm (3b). Integral intensity of the cyclo-
pentadiene protons was used for the assignment of the isomers.
Isomer 3a gives two singlets of the cyclopentadiene CH groups that
were observed at 5.79 and 4.84 ppm while 3a gives one singlet of
the CH2 group at 3.65 ppm. Infrared spectrum of 3 shows one very
strong band of CO stretching at 1721 cm–1. It proves the presence
of the ester group in the molecule. Fig. 2 shows the molecular
structure of isomer 3a that was determined by X-ray diffraction
analysis.
2.2. Characterization of compounds 2–4
Synthesis of compound 2 and its acid hydrolysis were followed
by NMR and infrared spectroscopy. Appearance of the compound 2
is evident from two very strong bands of CO stretching that were
found in the infrared spectrum at 1765 and 1720 cm–1. They were
assigned to mCO(CO) and mCO(COOMe), respectively. Compound 2
2.3. Synthesis and characterization of cyclopenta[l]phenanthrenyl
molybdenum compounds 7 and 8
gives a characteristic phenanthrene pattern in the 1H NMR spec-
trum (8.70–7.59 ppm), signals of CH (4.75 ppm), CH2 (3.91 ppm)
and CH3 group (3.70 ppm). Molecular structure of compound 2
determined by X-ray crystallography is shown in Fig. 1.
Ketone 4 shows only one band in the C@O stretching region at
1746 cm–1. The obtained NMR data are in agreement with those re-
ported previously [17].
Lithium salts of substituted cyclopenta[l]phenanthrenes (3-Li,
6-Li), prepared by treatment of 3 and 6 with one equivalent of
n-BuLi, react with [(
plexes 7 and 8, respectively (see Scheme 2). The complex 7
contains substituted cyclopenta[l]phenanthrenyl and
3-allyl
g g
3-C3H5)Mo(CO)2(NCMe)2Cl] to give 5-com-
g
The NMR spectroscopic measurements prove that CDCl3 solu-
tion of cyclopenta[l]phenanthrene 3 consists of isomers 3a and
3b, see Scheme 1. Their molar ratio was found to be 3:1. The 1H
NMR spectrum of 3 gives two series of signals at 8.71–6.63 ppm
ligand as is evident from NMR spectra. Signals of the allyl protons
were found at 2.86 (meso) 2.86 (syn), 0.99 (syn), 0.88 (anti) and 0.54
(anti). An infrared spectrum shows the carbonyl stretching in the
Fig. 2. ORTEP drawing of the compound 3a (ellipsoids: 30% probability). Number-
ing of all non-hydrogen atoms is shown. Selected bond lengths (Å) and bond angles
(°): C18–O1 = 1.203(2), C18–O2 = 1.329(2), C19–O2 = 1.446(2), C16–N1 = 1.348(2),
C20–N1 = 1.467(2), C23–N1 = 1.463(2), C16–N1–C20 = 121.44(12), C16–N1–
C23 = 125.17(14), C20–N1–C23 = 112.26(12).
Fig. 1. ORTEP drawing of the compound 2 (ellipsoids: 30% probability). Numbering
of all non-hydrogen atoms is shown. Selected bond lengths (Å): C16–O1 = 1.202(2),
C18–O2 = 1.202(2), C18–O3 = 1.334(2), C19–O3 = 1.444(2).

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J. Honzícek et al. / Journal of Organometallic Chemistry 695 (2010) 680–686
Scheme 2. Synthesis of allyl molybdenum(II) complexes 7 and 8.
range typical for [Cp0Mo( 3-C3H5)(CO)2] complexes
g (ma(CO) =
1936 cm–1 a(CO) = 1866 cm–1). The presence of the ester group
, m
is evident from the C@O stretching band that was observed at
1712 cm–1
The 1H NMR spectrum of compound 8 proves the presence of
.
two conformers generated by the orientation of the
g
3-coordi-
nated allyl ligand relative to the Cp0. At room temperature, the mo-
lar ratio between endo (8a) and exo (8b) conformer was found to be
3.7:1. The
g
5-bonded 2-methyl cyclopenta[l]phenanthrenyl gives a
characteristic pattern in the 1H NMR spectrum. It shows three mul-
tiplets of the phenanthrene protons at ꢀ8.4, 7.7 and 7.5 ppm, sin-
glet of the cyclopentadienyl part at ꢀ6.3 ppm and singlet of the
methyl group at ꢀ2.5 ppm. The infrared spectrum of the com-
pound 8 proves the presence of two carbonyl groups in the mole-
cule. The bands of the very strong intensity, which were assigned
to CO stretching, were observed at 1936 cm–1
(ma(CO)) and
Fig. 4. ORTEP drawing of the compound 8 (ellipsoids: 30% probability). Numbering
of all non-hydrogen atoms is shown. Selected bond lengths (Å) and bond angles (°):
Mo1–C19 = 1.949(2), Mo1–C20 = 1.949(2), Mo1–C21 = 2.322(2), Mo1–C22 =
2.183(4), Mo1–C22a = 2.362(4), Mo1–C23 = 2.335(2), Mo1–C13 = 2.4150(19),
Mo1–C14 = 2.4240(19), Mo1–C15 = 2.331(2), Mo1–C16 = 2.312(2), Mo1–C17 =
2.322(2), C19–O2 = 1.158(3), C20–O1 = 1.158(3), C19–Mo1–C20 = 79.38(9).
1833 cm–1
(m
s(CO)).
Structures of the complexes 7 and 8 were determined by X-ray
crystallography (Figs. 3 and 4). Both molecules have the pseudotet-
rahedral coordination around molybdenum atom with
g
3-allyl,
g
5-bonded substituted cyclopenta[l]phenanthrenyl and two car-
bonyl ligands. The allyl ligand of the compound 7 is in exo orienta-
tion. Bond lengths Mo–C(allyl) are 2.353(2), 2.221(2) and
2.312(2) Å. In compound 8, the allyl ligand has positional disorder.
It was refined in exo and endo orientation with 50% occupancy. The
The interplanar angles between two external six-membered rings
are 9.14(10)° for compound 7 and 6.92(10)° for compound 8. This
is consistent with structures of other
nyl compounds, in which the polycyclic ligand is also slightly
curved: [(
5-C17H10Me)TiCl3] [18], [( 5-C17H8Me3)Y(CH2Si-
Me3)2(THF)] [19], [( 2-CCSiM-
5-C17H8Me3)Y(CCSiMe3)(THF)]2[(
e3)2]ꢁTHF [19] and [(
5-C17H10Ph)Ru(CO)2Cl] [20].
g
5-cyclopenta[l]phenanthre-
distance between molybdenum atom and centroid of the g5
-
bonded cyclopenta[l]phenanthrenyl is 2.0382(8) Å for compound
7 and 2.0273(10) Å for compound 8. The Mo–C(Cp) distances vary
between 2.312(2) and 2.454(2) Å. The cyclopenta[l]phenanthrenyl
framework in compounds 7 and 8 is not planar but slightly arced.
g
g
g
l
g
The tert amino substituent in compound 7 shows almost trigo-
nal planar nitrogen atom. The sum of the angles at nitrogen atom is
351.5°. This is only slightly smaller than the corresponding value
found in the free cyclopenta[l]phenanthrene 3a (358.9°). The bond
lengths N–C(sp2) in both compounds are also almost identical
(7: 1.369(2) Å; 3a: 1.348(2) Å). In compounds 7, the methoxycar-
bonyl substituent is not coplanar with the five-membered ring.
The interplanar angle between COO group and five-membered ring
is 59.5(2)°. It contrasts with other molybdenum compounds that
have the COR group coplanar with the cyclopentadienyl ring:
[Cp0Mo(g3-C3H5)(CO)2] (Cp0 =
g g
5-C5H4COOMe [2]; 5-C5H4COMe
[21];
g
5-C5H4CO-Phe-OMe [13]).
2.4. Reactivity of cyclopenta[l]phenanthrenyl molybdenum
compounds 7 and 8
The attempted protonation of allyl compounds 7 and 8 was suc-
cessful only in case of compound 8. Reaction with HBF4 in presence
of acetonitrile gives ionic complex 9 in high yield. Protonation of
compounds 7 does not give any tractable product probably owing
to preference in protonation of the amino-group that gives unsta-
ble products.
NMR spectra of compound 9 prove coordination of two aceto-
nitriles. Signals of their protons are shifted to higher field
(1.80 ppm) compared to free acetonitrile (1.94 ppm). This is
Fig. 3. ORTEP drawing of the compound 7 (ellipsoids: 30% probability). Numbering
of all non-hydrogen atoms is shown. Selected bond lengths (Å) and bond angles (°):
Mo1–C27 = 1.942(2), Mo1–C28 = 1.944(2), Mo1–C24 = 2.353(2), Mo1–C25 =
2.221(2), Mo1–C26 = 2.312(2), Mo1–C13 = 2.3809(17), Mo1–C14 = 2.3993(16),
Mo1–C15 = 2.4539(18), Mo1–C16 = 2.3118(19), Mo1–C17 = 2.3287(18), C27–
O3 = 1.157(3), C28–O4 = 1.160(3), C22–O1 = 1.202(2), C22–O2 = 1.338(2), C23–O2
= 1.456(3), C15–N1 = 1.369(2), C18–N1 = 1.467(3), C21–N1 = 1.465(3), C27–Mo1–
C28 = 78.27(10), C15–N1–C18 = 122.85(16), C15–N1–C21 = 117.90(16), C18–N1–
C21 = 110.75(16).

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J. Honzícek et al. / Journal of Organometallic Chemistry 695 (2010) 680–686
683
apparently the effect of the benzene rings because the analogous
cyclopentadienyl compounds show shifting to the lower field
(d ꢀ2.2 ppm) [2,22]. Compound 9 has an infrared spectrum with
the pattern characteristic of the complexes of the type [Cp0Mo
(CO)2(NCMe)2]+. It has two medium intensity bands in the region
of CN stretching (at 2317 and 2284 cm–1), two bands of very strong
intensity in the region of the terminal carbonyl ligands (at 1982
and 1889 cm–1) and a broad band of very strong intensity at
1060 cm–1 that was assigned to B–F stretching. The compound
9 was characterized by positive-ion ESI mass spectroscopy. It gives
peaks of [Cp0Mo(CO)2(NCMe)2]+ (m/z = 465) and [Cp0Mo
(CO)2(NCMe)]+ (m/z = 424).
compound 7 is not presently understood and a more detailed study
of the amino-group effect is currently under way.
Within this study it was proven that compound 9 is an appro-
priate building block for the assembly of the CpCp0Mo moiety since
its reaction with cyclopentadiene followed by oxidation produced
the modified metallocene derivative [(g g
5-C5H5)( 5-C17H10Me)-
Mo(CO)2]2+ (11). Such highly functionalized molybdenocenes
may be of use in biomedical applications where the simplest,
non-functionalized Cp2MoX2 complexes have already revealed
some interesting antitumor activity.
The compound 9 reacts with cyclopentadiene giving
g
4-diene
4. Experimental
complex 10 (Scheme 3). Coordination of the cyclopentadiene was
evidenced by NMR spectroscopy. The 1H NMR spectrum shows
All operations were performed under nitrogen using conven-
tional Schlenk-line techniques. The solvents were purified and
dried by standard methods [27]. [(
[10], 3a-hydroxy-2-oxo-3,3a-dihydro-2H-cyclopenta[l]phenan-
the typical pattern for the
g
4-coordinated cyclopentadiene with
g
3-C3H5)Mo(CO)2(NCMe)2Cl]
two triplets at 5.29 and 4.30 ppm (3J(1H,1H) = 2.5 Hz) and two dou-
blets at 4.30 and 3.49 ppm (2J(1H,1H) = 14.5 Hz). The vibrations of
the carbonyl ligands were found in the infrared spectra at 2025
threne-1-carboxylic acid methyl ester (1) [15] and 2-methyl-1H-
cyclopenta[l]phenanthrene (6) [16] were prepared according to
literature procedures. 1H and 13C{1H} NMR spectra were measured
in CDCl3 and CD3CN solutions on Bruker Avance 400 spectrometer
at room temperature. Chemical shifts are given in ppm relative to
TMS. The infrared spectra were recorded in the 4000–440 cm–1 re-
gion (step 2 cm–1) on a Mattson 7000 FT-IR spectrometer using KBr
pellets. Positive and negative-ion electrospray ionization (ESI)
mass spectra were recorded on API-ION TRAP (PO 03 MS). Samples
were measured in MeCN solution. The molybdenum containing
ions had a clearly visible metal isotope pattern, arising from the
distribution: 92Mo 14.84%, 94Mo 9.25%, 95Mo 15.92%, 96Mo
16.68%, 97Mo 9.55%, 98Mo 24.13%, 100Mo 9.63%.37 Spectra obtained
were computer simulated (WSearch32 2005).
and 1948 cm–1
.
Dicationic molybdenum(IV) compound 11 was obtained
through oxidation of compound 10 by Br2. The 1H NMR spectrum
shows the singlet of the
g
5-bonded cyclopentadienyl ring at
6.09 ppm in addition to 2-methyl cyclopenta[l]phenanthrenyl pat-
tern that was described above. Compound 11 gives the infrared
spectrum with bands of the CO stretching at 2110 and 2060 cm–
1. Positive-ion ESI mass spectrum of the compound 11 shows two
peaks with pattern characteristic for dications. They were assigned
to [CpCp0Mo(CO)2]2+ (m/z = 224) and [CpCp0Mo]2+ (m/z = 196).
3. Conclusions
Synthesis of amino-functionalized cyclopentadienes [23,24]
and indenes [23–26] through reaction of the cyclopentenone (inda-
none) with secondary amines and their use for synthesis of the
transition metal complexes [22–26] was the subject of several
studies. However this is the first example of applying this method
to the synthesis of the cyclopentadienyl-based framework contain-
ing both tertiary amino and carboxylic ester groups.
4.1. Synthesis of 2-oxo-2,3-dihydro-1H-cyclopenta[l]phenanthrene-1-
carboxylic acid methyl ester (2)
Compound 1 (18.6 g; 61 mmol) was suspended in 30 ml of HI
(55% aqueous solution) and heated at 120 °C for 1 h. The resulting
brown solid was removed by filtration and washed with water. The
product was boiled with 10% aqueous solution of NaHSO3. The
crude product was filtered, washed with water and Soxhlet ex-
tracted with acetone. After first three extraction cycles the brown
solution was replaced with pure solvent. Yield: 15.8 g (54 mmol;
90%). Anal. Calc. for C19H14O3: C, 78.61; H, 4.86. Found: C, 78.56;
H, 5.22%. 1H NMR (CDCl3; 400 MHz): 8.70 (d, 3J(1H,1H) = 8.0 Hz,
2H, C14H8), 7.74–7.59 (m, 6H, C14H8), 4.75 (s, 1H, CHCOOMe),
3.91 (AX2, 2H, CH2), 3.70 (s, 3H, COOCH3). 13C NMR (CDCl3;
101 MHz): 207.3 (CO), 168.5 (COOMe), 134.5, 131.6, 130.8, 130.6,
128.6, 128.5 (6 ꢂ Cipso, C14H8), 127.7, 127.6, 127.5, 127.1, 125.6,
124.8, 123.7, 123.6 (8 ꢂ C, C14H8), 60.7 (COOCH3), 53.2 (CHCO-
For this purpose, we have optimized the synthesis of methoxy-
carbonyl-substituted ketone 2 and used it for the assembly of
substituted cyclopenta[l]phenanthrene 3. It was found that lithium
salt 3-Li reacts with [(
5-complex [( 5-C17H9(COOMe)N(CH2)4)(
Its analogue without the functional groups [(
g
3-C3H5)Mo(CO)2(NCMe)2Cl] to give stable
g
g
g
3-C3H5)Mo(CO)2] (7).
5-C17H10Me)(g3
g
-
C3H5)Mo(CO)2] (8) was prepared using a similar procedure. Both
molybdenum(II) compounds were isolated and characterized by
spectroscopic methods and X-ray crystallography.
Although compounds 7 and 8 are structural analogues their
reactivity is very different. Protonation of 8 with HBF4 gives cation
OMe), 43.1 (CH2). FTIR (KBr, cm–1): 1765 vs [
vs [ (CO) of COOMe]. The crystals suitable for X-ray analysis were
obtained upon slow evaporation of CH2Cl2 solution.
m(CO) of C@O], 1720
[(
g
5-C17H10Me)Mo(CO)2(NCMe)2]+ (9) while compound 7 decom-
m
poses under the same conditions. The unusual reactivity of the
Scheme 3. Assembly of the CpCp0Mo moiety via
g
4-C5H6 intermediate.

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684
4.2. Synthesis of 2-pyrrolidin-1-yl-H-cyclopenta[l]phenanthrene-1-
carboxylic acid methyl ester (3)
Calc. for C28H26MoNO4: C, 62.69; H, 4.89; N, 2.61. Found: C, 62.99;
H, 5.21; N, 2.67%. 1H NMR (CDCl3; 400 MHz): 8.49 (m, 1H, C17H9),
8.42 (d, 3J(1H,1H) = 8.1 Hz, 1H, C17H9), 7.84 (d, 3J(1H,1H) = 8.1 Hz,
1H, C17H9), 7.71 (m, 1H, C17H9), 7.51 (m, 4H, C17H9), 7.78 (s, 1H,
Compound 2 (2.7 g; 9.3 mmol) was suspended in methanol
(50 ml) and treated with an excess of pyrrolidine (3 ml). The mix-
ture was refluxed for 5 min and filtered after cooling at room tem-
perature. The yellow solid was washed with acetone. The crude
product was extracted using acetone in Soxhlet extractor. Crystals
suitable for X-ray analysis were obtained upon slow evaporation of
acetone solution. Yield: 2.04 g; 5.9 mmol; 64%. Anal. Calc. for
C23H21NO2: C, 80.44; H, 6.16; N, 4.08. Found: C, 80.39; H, 6.25; N,
4.11%. 1H NMR (CDCl3; 400 MHz): 3:1 mixture 3a and 3b, 8.71
(d, 3J(1H,1H) = 8.2 Hz, 1H of b, C14H8), 8.67 (d, 3J(1H,1H) = 7.7 Hz,
1H of a, C14H8), 8.62 (d, 1H of a and 1H of b, C14H8), 8.06–8.00
(m, 1H of a and 1H of b, C14H8), 7.90 (d, 3J(1H,1H) = 7.9 Hz, 1H of
a, C14H8), 7.75 (d, 3J(1H,1H) = 8.0 Hz, 1H of b, C14H8), 6.63–6.35
(m, 4H of a and 4H of b, C14H8), 5.79 (s, 1H of a, CH), 4.84 (s, 1H
of a, CH), 3.95 (s, 3H of b, COOCH3), 3.65 (s, 2H of b, CH2), 3.64
(s, 3H of a, COOCH3), 3.49–3.29 (m, 4H of a and 4H of b, C4H8N),
2.06–1.97 (m, 4H of a and 4H of b, C4H8N). 13C NMR (CDCl3;
101 MHz): 171.9 (a, COOMe), 170.5 (b, COOMe), 156.5 (b, C–N),
155.0 (a, C–N), 144.5 (Cipso, a, C14H8), 139.4 (Cipso, b, C14H8),
131.1, 129.6 (2 ꢂ Cipso, a, C14H8), 129.3 (Cipso, b, C14H8), 127.3,
127.2 (a, C14H8), 127.1, 127.0, 126.8, 126.3 (a, C14H8), 126.1 (a,
C14H8), 125.9, 125.5, 123.6 (a, C14H8), 123.5, 123.4, 123.3 (a,
C14H8), 122.9 (a, C14H8), 122.6, 121.9 (a, C14H8), 101.2 (b, C@),
94.9 (a, CH@), 56.6 (a, CHCOO), 52.8 (a, COOCH3), 51.6 (b, COOCH3),
50.5 (2C, b, C4H8N), 49.3 (2C, a, C4H8N), 39.4 (b, CH2), 25.9 (2C, b,
C
17H9), 3.98 (s, 3H, COOCH3), 3.20 (m, 4H, C4H8N), 2.86 (m, 1H meso
and 1H syn, C3H5), 2.00 (m, 4H, C4H8N), 0.99 (d, 3J(1H,1H) = 6.0 Hz,
1H, syn of C3H5), 0.88 (d, 3J(1H,1H) = 10.3 Hz, 1H, anti of C3H5), 0.54
(d, 3J(1H,1H) = 10.3 Hz, 1H, anti of C3H5). FTIR (KBr, cm–1): 1936 vs
[ma(CO)], 1866 vs [ms(CO)], 1712 vs [m(CO) of COOMe]. The crystals
suitable for X-ray analysis were prepared by careful overlayering of
the CH2Cl2 solution with Et2O.
4.7. Synthesis of [(g g
5-C17H10Me)( 3-C3H5)Mo(CO)2] (8)
The reaction was carried out as described for compound 7 but
with 2-methyl-1H-cyclopenta[l]phenanthrene (6) (1.16 g,
5 mmol). The crude product was recrystallized from Et2O and dried
in vacuo giving yellow powder of compound 8. Yield: 1.58 g
(3.7 mmol, 74%). Anal. Calc. for C23H18MoO2: C, 65.41; H, 4.30.
Found: C, 65.55; H, 4.36%. 1H NMR (CDCl3; 400 MHz; 3.7:1 mixture
8a (exo) and 8b (endo)): 8.42 (m, 2H of a and 2H of b, C17H10), 7.72
(m, 2H of a and 2H of b, C17H10), 7.51 (m, 4H of a and 4H of b,
C
17H10), 6.25 (s, 2H of a and 2H of b, C17H10), 3.28 (m, 1H of b, meso
of C3H5), 2.90 (d, 3J(1H,1H) = 6.1 Hz, 2H of b, syn of C3H5), 2.46 (s, 3H
of a and 2H of b, CH3), 1.8 (d, 3J(1H,1H) = 7.2 Hz, 2H of a, syn of
C3H5), 1.09 (m, 1H of a, meso of C3H5), 0.77 (d, 3J(1H,1H) = 10.9 Hz,
2H of a, anti of C3H5), ꢃ0.62 (d, 3J(1H,1H) = 10.8 Hz, 2H of b, anti of
C3H5). FTIR (KBr, cm–1): 1936 vs [
ma(CO)], 1833 vs [ms(CO)]. The
C4H8N), 25.8 (2C, a, C4H8N). FTIR (KBr, cm–1): 1721 vs [
m
(CO)].
crystals suitable for X-ray analysis were prepared upon slow evap-
oration of the CH2Cl2 solution.
4.3. Synthesis of 1,3-dihydro-cyclopenta[l]phenanthren-2-one (4)
4.8. Synthesis of [(
g
5-C17H10Me)Mo(CO)2(NCMe)2][BF4] (9)
Compound 2 (5.2 g; 18 mmol) was suspended in a mixture tfa–
water (4:1) and stirred under reflux for 6 h. The white precipitate
of the product was obtained upon cooling to room temperature.
It was filtered on glass frit, washed with water and vacuum dried.
Yield: 3.6 g; 15 mmol; 86%. Anal. Calc. for C17H12O: C, 87.90; H,
5.21. Found: C, 88.07; H, 5.28%. NMR data are in agreement
with those reported previously [17]. FTIR (KBr, cm–1): 1746 vs
[(
g
5-C15H10Me)(
g
3-C3H5)Mo(CO)2] (8) (1.40 g, 3.3 mmol) was
partially dissolved in a mixture CH2Cl2/MeCN (1:10), cooled at
0 °C and treated with one equivalent of HBF4ꢁEt2O. After 10 min
the reaction mixture was warmed up to room temperature and
stirred for additional 1 h. During that time the rest of the yellow
solid has dissolved and the solution changed to dark red. The sol-
vents were vacuum evaporated and the crude product was recrys-
tallized from MeCN/Et2O, washed with Et2O and vacuum dried
giving a red solid. Yield: 1.71 g (3.1 mmol, 94%). Anal. Calc. for
C24H19MoBF4N2O2: C, 52.32; H, 3.48; N, 5.09. Found: C, 52.46; H,
3.27; N, 5.18%. Positive-ion MS: m/z = 465 [M–BF4]+, 424 (100%)
[M–BF4–MeCN]+. Negative-ion MS: m/z = 87 (100%). 1H NMR
(CDCl3; 400 MHz): 8.63 (d, 3J(1H,1H) = 8.2 Hz, 2H, C17H10), 7.89 (d,
[m(CO)].
4.4. 2-Methyl-2,3-dihydro-1H-cyclopenta[l]phenanthren-2-ol (5)
Spectroscopic data are in agreement with those reported previ-
ously [16]. 13C NMR (CDCl3; 101 MHz): 135.3, 130.5, 130.1
(3 ꢂ 2Cipso, C14H8), 126.9, 126.1, 125.0, 123.4 (4 ꢂ 2C, C14H8), 79.6
(1C, COHMe), 48.3 (2C, CH2), 28.7 (1C, CH3).
3J(1H,1H) = 7.8 Hz, 2H,
C
17H10), 7.75 (t, 3J(1H,1H) = 7.7 Hz, 2H,
17H10), 7.65 (t, 3J(1H,1H) = 7.5 Hz, 2H,
17H10), 6.27 (s, 2H,
17H10), 2.06 (s, 3H, CH3), 1.80 (s, 6H, CH3CN). 13C NMR (CDCl3;
C
C
C
4.5. 2-Methyl-1H-cyclopenta[l]phenanthrene (6)
101 MHz): 250.1 (2C, CO), 140.0 (2C, CH3CN), 131.3 (2Cipso
C17H10), 129.4 (2C, C17H10), 128.4 (2C, C17H10), 126.7 (2Cipso
C17H10), 125.3 (2C, C17H10), 124.8 (2C, C17H10), 115.0 (2Cipso
,
,
,
Spectroscopic data are in agreement with those reported previ-
ously [16]. 13C NMR (CDCl3; 101 MHz): 146.2, 140.4, 137.3, 130.4,
129.9, 128.5, 127.7 (7Cipso), 126.9, 126.5, 125.7, 125.3, 124.8, 124.6,
123.8, 123.6, 123.5 (9C, CH), 43.1 (1C, CH2), 17.2 (1C, CH3).
C17H10), 106.8 (Cipso, C17H10), 80.0 (2C, C17H10), 15.5 (CH3), 3.1
(2C, CH3CN). FTIR (KBr, cm–1): 2317 m [
a(CN)], 2284 m [ s(CN)],
1982 vs [ a(CO)], 1889 vs [ s(CO)], 1060 vs–br [ s(BF)].
m
m
m
m
m
4.6. Synthesis of [(g g
5-C17H9(COOMe)N(CH2)4)( 3-C3H5)Mo(CO)2] (7)
4.9. Synthesis of [(
g
4-C5H6)( 5-C17H10Me)Mo(CO)2][BF4] (10)
g
Compound 3 (1.7 g, 5 mmol) was diluted with 30 ml of THF,
cooled at 0 °C and treated dropwise with 3.1 ml of n-BuLi
(1.6 mol l–1). The reaction mixture was stirred overnight and added
The solution of compound 9 (1.50 g, 2.7 mmol) in CH2Cl2 was
treated with an excess of freshly distilled cyclopentadiene (1 ml,
12 mmol). After stirring the reaction mixture for 16 h, the volatiles
were evaporated in vacuo. The crude product was washed with
ether and small amount of CH2Cl2. The yellow powder of com-
pound 10 was obtained after recrystallization from CH2Cl2/hexane.
Yield: 1.42 g (2.7 mmol, 97%). Anal. Calc. for C25H19BF4MoO2: C,
56.21; H, 3.59. Found: C, 56.45; H, 3.37%. 1H NMR (CDCl3;
dropwise to the THF solution of [(g
3-C3H5)Mo(CO)2(NCMe)2Cl]
(1.55 g, 5 mmol) precooled to ꢃ80 °C. The reaction mixture was
stirred at room temperature overnight and then vacuum evapo-
rated to dryness. The solid residue was washed twice with hot hex-
ane and then extracted with toluene. The yellow extract was
evaporated to dryness in vacuo. Yield: 1.12 g (2.1 mmol, 42%). Anal.

ˇ
J. Honzícek et al. / Journal of Organometallic Chemistry 695 (2010) 680–686
685
Table 1
Crystallographic data for compounds 2, 3a, 7 and 8.
2
3a
7
8
Formula
C19H14O3
290.30
C23H21NO2
343.41
C28H25MoNO4
535.43
Orthorhombic
P212121 (No. 19)
9.4628(3)
13.8899(4)
17.4635(6)
–
C23H13MoO2
422.31
Formula weight
Crystal system
Space group
a (Å)
b (Å)
c (Å)
Monoclinic
P21/c (No. 14)
10.0410(6)
16.4183(8)
9.1010(4)
–
Monoclinic
P21/n (No. 14)
8.8477(7)
14.8554(12)
12.8897(11)
–
Monoclinic
P21/c (No. 14)
10.6513(6)
14.9502(9)
11.6555(6)
–
a
(°)
b (°)
113.009(2)
–
1380.99(12)
4
1.396
0.094
92.755(5)
–
1692.2(2)
4
1.348
0.086
–
–
109.084(2)
–
1754.00(17)
4
1.599
0.762
c
(°)
V (Å3)
Z
2295.36(13)
4
1.549
Dc (g cm–3
)
l
(mm–1
)
0.608
F (0 0 0)
608
728
1096
856
Crystal size (mm)
h Range
Index ranges
0.10 ꢂ 0.08 ꢂ 0.06
2.53–25.00
–11 6 h 6 10
–18 6 k 6 19
–10 6 l 6 10
11 975
2358 (Rint = 0.028)
204
R1 = 0.0365, wR2 = 0.1112
R1 = 0.0499, wR2 = 0.1267
0.216, –0.182
0.18 ꢂ 0.12 ꢂ 0.10
2.68–29.69
–12 6 h 6 12
–19 6 k 6 20
–17 6 l 6 17
17 113
4657 (Rint = 0.037)
244
R1 = 0.0545, wR2 = 0.1448
R1 = 0.0861, wR2 = 0.1647
0.452, –0.269
0.30 ꢂ 0.20 ꢂ 0.10
1.87–33.00
–14 6 h 6 12
–20 6 k 6 20
–25 6 l 6 24
27 680
7324 (Rint = 0.028)
308
R1 = 0.0255, wR2 = 0.0664
R1 = 0.0280, wR2 = 0.0734
0.413, –0.445
0.20 ꢂ 0.20 ꢂ 0.08
2.44–24.99
–12 6 h 6 12
–17 6 k 6 17
–13 6 l 6 13
26 600
3089 (Rint = 0.020)
245
R1 = 0.0205, wR2 = 0.0571
R1 = 0.0214, wR2 = 0.0578
0.513, –0.395
Reflections collected
Independent reflections
Parameters
Final R indices [I > 2
r
(I)]a,b
Final R indices (all data)a,b
Largest difference in peak and hole (e Å–3
)
P
P
a
R1
¼
kFoj ꢃ jFck= jFoj:
qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
P
P
2
2
b
wR2
¼
½wðF2o ꢃ Fc2Þ ꢄ= ½wðF2o Þ ꢄ:
400 MHz): 8.52 (m, 2H, C17H10), 8.14 (m, 2H, C17H10), 7.74 (m, 4H,
hydrogen atoms were refined anisotropically. The allyl group in
compound 8 was disordered and the central carbon atom C22
(and C22a) was refined with 50% occupancy.
C
17H10), 6.63 (s, 2H, C17H10), 5.29 (t, 3J(1H,1H) = 2.5 Hz, 2H, C5H6),
4.30 (t, 3J(1H,1H) = 2.5 Hz, 2H, C5H6), 3.49 (d, 2J(1H,1H) = 14.5 Hz,
2H, C5H6), 3.17 (d, 2J(1H,1H) = 14.5 Hz, 2H, C5H6), 2.40 (s, 3H,
CH3). FTIR (KBr, cm–1): 2025 vs [
ma(CO)], 1948 vs [ms(CO)], 1049
Acknowledgments
vs–br [
ms(BF)].
This project was supported through grant projects SFRH/BPD/
24889/2005 (FCT, Portugal), GACR/203/09/P100 (GACR, Czech
Republic) and MSM 0021627501 (MSMT, Czech Republic). We
thank FCT (Portugal) for the funding of purchasing the single-crys-
tal diffractometer. The NMR spectrometers are part of the National
NMR Network and were acquired with funds from FCT and FEDER.
We wish to acknowledge Maria da Conceição Almeida for provid-
ing elemental analysis and mass spectrometry service (ITQB-UNL,
Portugal) and Paula Brandão from the Universidade de Aveiro for
crystal mounting and data collection.
4.10. Synthesis of [(
g
5-C5H5)( 5-C17H10Me)Mo(CO)2][Br][BF4] (11)
g
The solution of compound 10 (1.30 g, 2.4 mmol) in CH2Cl2 was
cooled at ꢃ80 °C and treated with an excess of bromine. The solu-
tion was stirred for 10 min at 0 °C. During that time an orange pre-
cipitate was formed. Solvents and the excess of bromine were
vacuum evaporated. Product was washed three times with CH2Cl2,
twice with ether, recrystallized from MeCN/Et2O and vacuum
dried. Yield: 1.12 g (1.8 mmol, 75%). Anal. Calc. for
C25H18BBrF4MoO2: C, 48.98; H, 2.96. Found: C, 48.74; H, 2.77%. Po-
sitive-ion MS: m/z = 224 [M–Br–BF4]2+, 196 (100%) [M–Br–BF4–
Appendix A. Supplementary material
2CO]2+
2H,
17H10), 8.48 (d, 3J(1H,1H) = 7.4 Hz, 2H,
3J(1H,1H) = 7.8 Hz, 2H, 17H10), 7.94 (t, 3J(1H,1H) = 7.7 Hz, 2H,
17H10), 6.09 (s, 5H, C5H5), 5.68 (s, 2H, C17H10), 2.65 (s, 3H, CH3).
FTIR (KBr, cm–1): 2110 vs [
a(CO)], 2060 vs [ s(CO)], 1067 vs–br
s(BF)].
.
1H NMR (CD3CN; 400 MHz): 8.81 (d, 3J(1H,1H) = 8.3 Hz,
C
C
17H10), 8.03 (t,
CCDC 721845, 721846, 721847, 721848 contain the supplemen-
tary crystallographic data for 2, 3a, 7 and 8. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data
Center via http://www.ccdc.cam.ac.uk/data_request/cif. Supple-
mentary data associated with this article can be found, in the on-
line version, at doi:10.1016/j.jorganchem.2009.11.043.
C
C
m
m
[
m
4.11. X-ray structure determination
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CCD diffractometer using graphite-monochromated Mo K radia-
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