Synthesis and expansion reaction of ferrocenylacetylene dimetal carbonyl compounds. The molecular structures of μ-FcCCHCoMo(CO)5Cp and μ3-FcCHCFeCo2(CO)9

Article abstract of DOI:10.1016/S0022-328X(98)00813-4

Two ferrocenylacetylene dimetal carbonyl clusters μ-FcCCHCo(CO)₃M(CO)₂Cp (2, M=Mo; 3, M=W) were obtained from the reactions of the precursor μ-FcCCHCo₂(CO)₆ 1 with metal exchange reagents NaM(CO)₃Cp in THF under reflux. The dimetal compounds 1, 2, and 3 can further react with Fe₂(CO)₉ in the presence of benzylideneacetone (BDA) to give the corresponding μ₃-ferrocenylvinylidene bridged trimetal clusters μ₃-FcCHCFeCo₂(CO)₉ 4 and μ₃-FcCHCFeCoM(CO)₈Cp (5, M=Mo; 6, M=W), respectively, probably through the formation of the intermediate (BDA)Fe(CO)₃ which acts as an Fe(CO)₃ transfer-reagent. The new compounds 2-6 were characterized by C/H analysis, IR and ¹H-NMR spectrocopies. The molecular structures of 2 and 4 were determined by X-ray structural analysis. 2 is triclinic with space group P1 (#2), a=8.733(2) A, b=14.870(3) A, c=8.200(2) A, α=92.77(2)°, β=101.78(2)°, γ=78.41(2)°, V=1021.2(4) A³, and Z=2; final R=0.025, R_w=0.034 for 2988 reflections. Cluster 4 is orthorhombic with space group P2₁2₁2₁ (#19), a=12.186(5) A, b=14.870(5) A, c=7.800(6) A, V=2340(2) A³ and Z=4; final R=0.062, R_w=0.065 for 2401 reflections.

Full text of DOI:10.1016/S0022-328X(98)00813-4

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Journal of Organometallic Chemistry 570 (1998) 71–78
Synthesis and expansion reaction of ferrocenylacetylene dimetal
carbonyl compounds. The molecular structures of
v-FcCCHCoMo(CO)5Cp and v3-FcCHCFeCo2(CO)9
Shu-Lin Wu a, Er-Run Ding a, Yuan-Qi Yin a,*, Jie Sun b
a State Key Laboratory of Oxo Synthesis and Selecti6e Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences,
Lanzhou 730000, People’s Republic of China
b Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, People’s Republic of China
Received 28 April 1998; received in revised form 26 June 1998
Abstract
Two ferrocenylacetylene dimetal carbonyl clusters v-FcCCHCo(CO)3M(CO)2Cp (2, M=Mo; 3, M=W) were obtained from
the reactions of the precursor v-FcCCHCo2(CO)6 1 with metal exchange reagents NaM(CO)3Cp in THF under reflux. The
dimetal compounds 1, 2, and 3 can further react with Fe2(CO)9 in the presence of benzylideneacetone (BDA) to give the
corresponding v3-ferrocenylvinylidene bridged trimetal clusters v3-FcCHCFeCo2(CO)9 4 and v3-FcCHCFeCoM(CO)8Cp (5,
M=Mo; 6, M=W), respectively, probably through the formation of the intermediate (BDA)Fe(CO)3 which acts as an Fe(CO)3
1
transfer-reagent. The new compounds 2–6 were characterized by C/H analysis, IR and H-NMR spectrocopies. The molecular
˚
(
structures of 2 and 4 were determined by X-ray structural analysis. 2 is triclinic with space group P1 (c2), a=8.733(2) A,
3
˚
˚
˚
b=14.870(3) A, c=8.200(2) A, h=92.77(2)°, i=101.78(2)°, k=78.41(2)°, V=1021.2(4) A , and Z=2; final R=0.025,
˚
˚
Rw=0.034 for 2988 reflections. Cluster 4 is orthorhombic with space group P212121 (c19), a=12.186(5) A, b=14.870(5) A,
3
˚
˚
c=7.800(6) A, V=2340(2) A and Z=4; final R=0.062, Rw=0.065 for 2401 reflections. © 1998 Elsevier Science S.A. All rights
reserved.
Keywords: Ferrocenylacetylene; Dimetal clusters; Trimetal clusters; Expansion
could serve as model compounds in heterogeneous
catalysis. A ligand bonded to metal cluster can simulate
the absorption of same species on metal surface and,
are of interesting alkyne-bridged ligand rearrangement
[3] and diastereoselective transformation [4] on tri- or
quart-metal clusters.
An astonishing variety of alkyne-bridged clusters
have been synthesized and structurally characterized.
However, reports on the ferrocenylacetylene cluster
compounds are relatively rare in the literature [5] and
no example of ferrocenylacetylene heterometal clusters
has been investigated. Others [6] and we believed that
incorporation of the ferrocenyl group into clusters
through an organic conjugated bridge would lead to
some interesting properties based on the well-known
1. Introduction
Transition metal carbonyl clusters are regarded as
model system whose study can provide insight into the
complicated reaction processes at catalytically active
metal surfaces. This fact, together with the hope of
employing the cluster themselves in catalytic processes,
has led to a considerable research potential in this area
[1]. Alkyne and alkynyl species bearing a CꢀC func-
tional group belong to a class of surface species which
may play pivotal role in various catalytic reactions such
as CO hydrogenation (F-T processes) [2], therefore,
alkyne-bridged di- or polynuclear metal carbonyls
* Corresponding author. Fax: +86 931 8417088.
0022-328X/98/$ - see front matter © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00813-4

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S.-L. Wu et al. / Journal of Organometallic Chemistry 570 (1998) 71–78
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Scheme 1.
Scheme 2.
fact: both ferrocene [7] and low-valency transition-
metal clusters [8] can function as redox centers electron-
transfer entities. In this article we report the synthesis
of ferrocenylacetylene heterodimetal clusters, and their
expansion reaction with Fe2(CO)9 in the presence of
benzene was stirred for 16 h at room temperature. The
solvent was removed under reduced pressure to yield a
dark-green crystalline residue. Chromatography on a
2.5×60 cm column of silica gel eluting with petroleum
ether. First removed a small yellow band (FcCꢀCH),
Further elusion with petroleum ether gave a large green
band which was collected and evaporated to dryness to
afford 4.50 g (80.4%) of dark-green crystals of 1. Anal.
Calc. for C18H10O6FeCO2: C, 43.44; H, 2.03%. Found:
C, 43.38; H, 2.07%. IR (KBr disk): 3103m, 2087s,
benzylideneacetonetricarbonyliron.
The
molecular
structures of 2 and 4 were determined by X-ray
diffraction.
1
2048vs, 2019–1850vs(br.) cm−1. H-NMR (DCC13, l):
2. Experimental
6.28(s. 1H, C–H), 4.35(s, 4H, C5H4), 4.16(s, 5H, C5H5).
Mo(CO)6 (0.264 g, 1.0 mmol) was added to a solu-
tion of ca. 1.0 mmol sodium pentadienide in 25 ml
THF. The mixture was heated under reflux for 12 h and
cooled to room temperature. Then 1 (0.500 g, 1.0
mmol) was added and stirred for 1.5 h at 60°C. The
solvent was removed under vacuum. The red-brown
residue was chromatographed on a 2.5×20 cm silica
gel column using petroleum ether/CH2Cl2 as eluent and
gave 0.440 g (76.9%) of dark-red solid 2. Anal. Calc. for
C22H15O5FeCoMo: C, 46.36; H, 2.63%. Found: C,
46.38; H, 2.51%. IR (KBr disk): 3096m, 2050s, 1983vs.
2.1. General details
All reactions were carried out under prepurified ni-
trogen atmosphere using standard Schlenk or vacuum
line techniques. All solvents were dried and deoxy-
genated according to standard procedures [9] before
use. Chromatographic separations and purlfications
were performed on 160–200 mesh silica gel. Mo(CO)6,
W(CO)6, and Fe2(CO) were purchased from Fluka and
Aldrich Chem. v-FcCCHCo2(CO)6 ([5]a) and benzyli-
deneacetonetricarbonyliron (BDA)Fe(CO)3 [10] were
prepared according to the literature methods.
1
1959vs, 1927s cm−1. H-NMR(CDCl3, l): 5.96(s, 1H,
IR spectra were recorded on a Nicolet FT-IR spec-
trophotometer,1H-NMR were recorded on a Bruck AM
400 MHz spectrometer. C/H determination was per-
formed using a Carlo-Erba 1160 type microanalyzer.
2.2. Synthesis of clusters 1, 2 and 3
A solution of Co2(CO)8 (4.20 g, 12.3 mmol) and
ferrocenylacetylene (2.60 g, 12.4 bmmol) in 100 ml
Scheme 3.

S.-L. Wu et al. / Journal of Organometallic Chemistry 570 (1998) 71–78
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73
Fig. 1. Molecular structure of 2
C–H), 5.36(s, 5H, C5H5Mo), 4.18(s, 4H, C5H4Fe),
4.13(s, 5H, C5H5Fe).
toluene was stirred at 55–60°C for 48 h. The solvent
was removed and the residue was loaded onto a chro-
matographic column. Elution with petroleum ether re-
moved trace of 1 and Fe3(CO)12. Then elusion with
petroleum ether/CH2Cl2 (7:1) produced a dark red-
brown band of v3-FcCHCFeCo2(CO)9 4 (0.215 g,
66.0%), and followed by an orange band of
(BDA)Fe(CO)3 (0.018 g).
Complex 3 was prepared by the same procedure as
that of for 2, W(CO)6 was used instead of Mo(CO)6. A
total of 0.400 g (60.7%) of 3 was obtained as a dark-red
solid. Anal. Calc. for C22H15O5FeCoW: C, 39.67; H,
1.59%. Found: C, 39.52; H, 1.61%. IR (KBr disk):
1
3094m, 2047s, 1987vs, 1956vs, 1921s cm−1. H-NMR(-
Complex 4: Anal. Calc. for C21H10O9Fe2CO2: C,
39.67; H, 1.59%. Found: C, 39.52; H, 1.61%. IR (KBr
disk): 3095m, 2095s, 2056s, 2027vs, 2008vs, 1971s
CDC13, l): 5.83(s, 1H, C–H), 5.27(s, 5H, C5H5W),
4.11 (s, 4H, C5H4Fe), 4.06(s, 5H, C5H5Fe).
1
cm−1. H-NMR(CDCl3, l): 6.84(s, 1H, C–H), 4.33–
2.3. Expansion reaction of 1, 2 and 3
4.40 (m, 4H, C5H4Fe), 4.24 (s, 5H, C5H5Fe).
Complex 4 can also be obtained by the reaction of 1
with (BDA)Fe(CO)3 (1:3) in the similar reaction condi-
tion in 58% yield.
These reactions were carried out at 55–60°C in
toluene with ca. 1:2:3 ratios of the dimetal clusters,
BDA and Fe2(CO)9. A detailed description of the reac-
tion among 1, BDA and Fe2(CO)9 is provided to illus-
trate the procedure. Other reactions and workup were
conducted similarly.
v3-FcCHCFeCoMo(CO)8Cp 5 was obtained from 2
in 66.9% as
a dark-red solid. Anal. Calc. for
C25H15O8CoFe2Mo: C, 42.29; H, 2.13. Found: C, 42.45;
H, 2.08%. IR (KBr disk): 3100m, 2064s, 2004vs, 1939vs,
1
1888s cm−1. H-NMR(CDCl3, l), 6.81, 6.62(s, s, ca.
A solution of 1 (0.250 g, 0.5 mmol), BDA (0.146 g,
1.0 mmol) and Fe2(CO)9 (0.546 g, 1.5 mmol) in 30 ml
1:1, 1H, C–H), 5.74 (s, 5H, C5H5Mo), 4.24(m, 9H, Fc).

74
S.-L. Wu et al. / Journal of Organometallic Chemistry 570 (1998) 71–78
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Fig. 2. Molecular structure of 4
v3-FcCHCFeCoW(CO)8Cp 6 was obtained from 3 in
62.7% as dark red solid 6. Anal. Calc. for
tions were performed using the teXsan crystallographic
software package of Molecular Structure Corporation.
a
C25H15O8CoFe2W: C, 37.63; H, 1.89%. Found: C,
37.54; H, 1.92%. IR (KBr disk): 3094m, 2062s, 2002vs,
1935vs, 1883s cm−1. H-NMR (CDCl3, l), 7.07, 6.46(s,
s, ca. 3:1, 1H, C–H), 5.59, 5.49(s, s ca. 3:1, 5H,
C5H5Mo), 4.23(m, 9H, Fc).
1
3. Results and discussion
3.1. Synthesis and characterization of 2 and 3
2.4. X-ray crystallography of 2 and 4
The reactions described in this work are summarized
in Scheme 1. Dicobalt Octacarbonyl reacts readily with
alkyne to give the (v-RCꢀCR%)Co2(CO)6 [12]. Similarly,
Yanez [13] and Coville [14] found CpM(CO)3Co(CO)3
(M=Mo, W) reacted with alkyne to afford (v-
RCꢀCR%)Co(CO)3M(CO)2Cp, but the yields were poor
and sometimes (RCꢀCR%)2Co(CO)2M(CO)Cp were the
major products. Isolobal substitution of a different
organometallic vertex on an appropriate alkyneho-
modimetal clusters which represents a logical routes to
synthesize heterometal clusters has attracted consider-
able attention [15]. Therefore, in the present work,
ferrocenylacetylene reacted with Co2(CO)8 in benzene
for 16 h at room temperature, cluster 1 was obtained in
80.4% yield. Complex 1 was treated with CpM(CO)3−
(M=Mo, W), which were prepared from M(CO)6 and
C5H5Na in situ, in THF under reflux during 1.5 h to
give cluster 2 and 3 in 76.8 and 60.7%, respectively. The
dimer M2(CO)4Cp2 were always present as byproducts.
When the reactions in the case of Mo were carried out
at an elevated temperature, for example, in DME under
Single crystals suitable for an X-ray diffraction anal-
ysis were obtained from hexane at −20°C. Both crys-
tals approximate dimensions 0.20×0.20×0.30 mm3
were chosen and mounted on glass fibres. All measure-
ments were made on a Rigaku AFC 7R diffractometer
˚
with graphite monochromated Mo–Kh (u=0.71069 A)
radiation. Cell constants and orientation matrix for
data collection, were obtained from a least-squares
refinement using the setting angles of 20 carefully cen-
tered reflections in the range 18.87B2qB24.46° for 2
and 13 reflections in the range 13.34B2qB21.50° for
4. The data were collected at a temperature of 20.0°C
using a ꢀ-2q scan technique with a scan rate of 16°
min−1
.
The structures were solved by direct methods and
expanded Fourier techniques. The non-hydrogen atoms
were refined anisotropically. Hydrogen atoms were in-
cluded but not refined. Neutral atoms scattering factors
were taken from Cromer and Waber [11]. All calcula-