Synthesis of the gold-dirhenium ferrocenylacetylide cluster. The crystal structure of Re2(μ-C≡CFc){Au(PPh3)}(CO)8

Article abstract of DOI:10.1023/A:1015060218877

The thermal reaction of Re₂(CO)₈(NCMe)₂ with Au(C≡CFc)PPh₃ afforded the cluster Re₂(μ-C≡CFc){Au(PPh₃)}(CO)₈, which was characterized by X-ray diffraction analysis.

Full text of DOI:10.1023/A:1015060218877

Russian Chemical Bulletin, International Edition, Vol. 50, No. 12, pp. 2441—2444, December, 2001
2441
Organometallic Chemistry
Synthesis of the gold-dirhenium ferrocenylacetylide cluster.
The crystal structure of Re2(µ-C≡CFc){Au(PPh3)}(CO)8
A. A. Koridze,« V. I. Zdanovich, A. M. Sheloumov, F. M. Dolgushin, M. G. Ezernitskaya, and P. V. Petrovskii
A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5085. Å-mail: koridze@ineos.ac.ru
The thermal reaction of Re2(CO)8(NCMe)2 with Au(C≡CFc)PPh3 afforded the cluster
Re2(µ-C≡CFc){Au(PPh3)}(CO)8, which was characterized by X-ray diffraction analysis.
Key words: acetylide complexes of gold and rhenium, gold-dirhenium cluster, X-ray
diffraction analysis, ferrocenylacetylenes.
One of the widely accepted procedures for the syn-
thesis of acetylide derivatives of transition metal clus-
ters1 is based on reactions of mononuclear acetylide
complexes with metal carbonyl clusters. This proce-
dure was used also for the preparation of mixed
gold-triosmium clusters. Thus the reactions of gold
acetylides Au(C≡CPh)L (L = PPh3 or PMe2Ph)
and Au(C≡CFc)PPh3 with Os3(CO)10(NCMe)2 af-
forded products of the oxidative addition of the
gold acetylide compounds to the Os3 clusters, viz.,
Os3(µ-C≡CPh)(AuL)(CO)10 (L = PPh3 (1a) or PMe2Ph
(1b))2 and Os3(µ3-C≡CFc){Au(PPh3)}(CO)9 (2),3 re-
spectively. In the present study, we synthesized a gold-
dirhenium ferrocenylacetylide cluster according to an
analogous reaction.
(3) in 77% yield (Scheme 1) and a small amount of
unidentified red compound 4. It should be noted
that a phenylacetylide analog of 3, viz., the com-
plex Re2(µ-C≡CPh){Au(PPh3)}(CO)8 (5), has been
prepared recently4 in 7% yield by the reaction of
Re2(µ-H)(µ-C≡CPh)(CO)8 with Na[Co(CO)4] and then
Scheme 1
∆
Re2(CO)8(NCMe)2 + Au(C CFc)PPh3
Fc
C
C
(CO)4Re
Re(CO)4
Results and Discussion
Au
The reaction of Re2(CO)8(NCMe)2 with
Au(C≡CFc)PPh3 in boiling toluene gave rise to orange
crystals of the complex Re2(µ-C≡CFc){Au(PPh3)}(CO)8
PPh3
3
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2331—2333, December, 2001.
1066-5285/01/5012-2441 $25.00 © 2001 Plenum Publishing Corporation

2442
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001
Koridze et al.
with AuCl(PPh3). The 1H NMR spectrum (in CDCl3)
of product 3 provides evidence for the presence of the
ferrocenyl group (δ 4.23 (5 H), 4.28 (2 H), and 4.58
(2 H)) and the phenyl groups of the triphenylphosphine
ligand. The 31P NMR spectrum of complex 3 has a
singlet signal at δ 82.01. For comparison, the 31P NMR
spectra of the complexes Au(C≡CFc)PPh3 and 2 have
signals at δ 43.18 and 72.86, respectively.3
C(14)
C(18)
C(13)
C(19)
C(20)
Fe(1)
C(15)
C(12)
C(11)
C(17)
C(16)
C(10)
C(9)
O(2)
O(3)
C(3)
The structure of complex 3 was established by single-
crystal X-ray diffraction analysis. The molecular struc-
ture of complex 3 is shown in Fig. 1. The selected
geometric parameters are given in Table 1. The mol-
ecule contains the triangular AuRe2 core. The ferro-
cenylacetylide ligand is σ,π-coordinated to two Re at-
oms. The Re(1)—Re(2) bond (3.1863(4) Å) in complex
3 is somewhat elongated as compared to the analogous
bond in Re2(CO)10 (3.041(1) Å).5 On the whole, the
structural parameters of complex 3 are close to those
found4 for phenylacetylide analog 5. The Re—Re dis-
tances in complexes 3 and 5 (3.1863(4) and 3.179(2) Å,
respectively) are somewhat larger than that (3.089(1) Å)
found6 in the hydridoacetylide complex Re2(µ-H)(µ-
C≡CPh)(CO)8 (6). The Re(1)—Au(1) and Re(2)—Au(1)
distances are nonequivalent (2.7326(4) and 2.8693(3) Å,
respectively). In tetranuclear gold-triosmium cluster 1b 2
containing the analogously σ,π-coordinated phenyl-
acetylide ligand, two Os—Au distances differ to a smaller
extent (2.770(1) and 2.794(1) Å), whereas the corre-
sponding Os—Au distances in cluster 2 3 containing the
σ,2π-coordinated ligand are 2.780(1) and 2.783(1) Å. In
O(7)
O(6)
C(6)
C(7)
C(2)
Re(1)
Re(2)
C(1)
C(4)
O(4)
O(5)
C(8)
O(8)
C(30)
O(1)
C(31)
Au(1)
C(32)
P(1)
C(33)
C(27)
C(38)
C(29)
C(37)
C(34)
C(28)
C(26)
C(35)
C(36)
C(21)
C(22)
C(25)
C(23)
Fig. 1. Molecular structure of cluster 3.
C(24)
Table 1. Selected bond lengths (d) and bond angles (ω) in complex 3
Bond
d/Å
Angle
ω/deg
Angle
ω/deg
Angle
ω/deg
Re(1)—Re(2) 3.1863(4)
Re(1)—C(1) 1.990(5)
Re(1)—C(2) 2.010(5)
Re(1)—C(3) 1.925(5)
Re(1)—C(4) 1.978(4)
Re(1)—C(9) 2.056(4)
Re(2)—C(5) 2.014(5)
Re(2)—C(6) 2.006(5)
Re(2)—C(7) 1.903(5)
Re(2)—C(8) 1.944(5)
Re(2)—C(9) 2.319(4)
Re(2)—C(10) 2.390(5)
Au(1)—Re(1) 2.7326(4)
Au(1)—Re(2) 2.8693(3)
P(1)—Au(1)—C(8)
97.96(11) Au(1)—Re(1)—Re(2) 57.382(6) C(9)—Re(2)—Re(1) 40.12(11)
P(1)—Au(1)—Re(1) 151.15(3)
C(8)—Au(1)—Re(1) 109.98(11) C(7)—Re(2)—C(6)
P(1)—Au(1)—Re(2) 137.72(3) C(8)—Re(2)—C(6)
C(8)—Au(1)—Re(2) 40.78(11) C(7)—Re(2)—C(5)
Re(1)—Au(1)—Re(2) 69.282(9) C(8)—Re(2)—C(5)
C(3)—Re(1)—C(4)
C(3)—Re(1)—C(1)
C(4)—Re(1)—C(1)
C(3)—Re(1)—C(2)
C(4)—Re(1)—C(2)
C(7)—Re(2)—C(8)
86.1(2)
89.8(2)
89.9(2)
C(10)—Re(2)—Re(1) 70.18(13)
Au(1)—Re(2)—Re(1) 53.336(9)
C(33)—P(1)—C(27) 106.1(2)
89.32(19) C(33)—P(1)—C(21) 104.5(2)
93.1(2)
C(27)—P(1)—C(21) 104.9(2)
C(33)—P(1)—Au(1) 114.92(15)
89.7(2)
92.7(2)
91.9(2)
95.9(2)
87.8(2)
C(6)—Re(2)—C(5) 176.8(2)
C(7)—Re(2)—C(9) 115.92(18) C(27)—P(1)—Au(1) 107.21(17)
C(8)—Re(2)—C(9) 157.86(18) C(21)—P(1)—Au(1) 118.23(16)
C(6)—Re(2)—C(9)
C(5)—Re(2)—C(9)
92.52(19) O(1)—C(1)—Re(1) 178.3(4)
85.07(18) O(2)—C(2)—Re(1) 177.6(5)
C(1)—Re(1)—C(2) 171.44(19) C(7)—Re(2)—C(10) 85.88(19) O(3)—C(3)—Re(1) 177.7(5)
C(3)—Re(1)—C(9) 92.85(19) C(8)—Re(2)—C(10) 171.93(19) O(4)—C(4)—Re(1) 176.1(5)
C(4)—Re(1)—C(9) 175.01(19) C(6)—Re(2)—C(10) 90.55(19) O(5)—C(5)—Re(2) 176.0(4)
Au(1)—P(1) 2.3306(12) C(1)—Re(1)—C(9)
Au(1)—C(8) 2.689(5) C(2)—Re(1)—C(9)
92.31(19) C(5)—Re(2)—C(10) 86.30(17) O(6)—C(6)—Re(2) 175.7(5)
87.63(19) C(9)—Re(2)—C(10) 30.12(17) O(7)—C(7)—Re(2) 175.3(4)
P(1)—C(33)
P(1)—C(27)
P(1)—C(21)
C(9)—C(10) 1.225(7)
C(10)—C(11) 1.456(6)
1.815(5)
1.816(5)
1.820(5)
C(3)—Re(1)—Au(1) 163.09(14) C(7)—Re(2)—Au(1) 150.62(14) O(8)—C(8)—Re(2) 169.9(5)
C(4)—Re(1)—Au(1) 73.66(14) C(8)—Re(2)—Au(1) 64.63(14) O(8)—C(8)—Au(1) 114.2(4)
C(1)—Re(1)—Au(1) 85.07(14) C(6)—Re(2)—Au(1) 88.30(15) Re(2)—C(8)—Au(1) 74.59(16)
C(2)—Re(1)—Au(1) 86.64(14) C(5)—Re(2)—Au(1) 93.98(13) C(10)—C(9)—Re(1) 170.5(4)
C(9)—Re(1)—Au(1) 103.98(12) C(9)—Re(2)—Au(1) 93.45(11) C(10)—C(9)—Re(2)
78.1(3)
C(3)—Re(1)—Re(2) 139.39(14) C(10)—Re(2)—Au(1) 123.44(13) Re(1)—C(9)—Re(2) 93.28(17)
C(4)—Re(1)—Re(2) 130.91(14) C(7)—Re(2)—Re(1) 156.04(14) C(9)—C(10)—C(11) 152.6(5)
C(1)—Re(1)—Re(2) 87.75(13) C(8)—Re(2)—Re(1) 117.86(14) C(9)—C(10)—Re(2)
71.7(3)
91.39(14) C(11)—C(10)—Re(2) 135.6(4)
88.15(13)
C(2)—Re(1)—Re(2) 85.99(14) C(6)—Re(2)—Re(1)
C(9)—Re(1)—Re(2) 46.61(12) C(5)—Re(2)—Re(1)

Crystal structure of Re2(µ-C≡CFc){Au(PPh3)}(CO)8 Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001 2443
Table 2. Crystallographic parameters and details of X-ray
diffraction study of compound 3
cluster 3, each Re atom is coordinated by four CO
groups. One of these groups, viz., C(8)O(8), is non-
linear (the Re(2)—C(8)—O(8) angle is 169.9(5)°) and
is semibridging in character due to a weak interac-
tion with the Au atom (the C(8)—Au(1) distance is
2.689(5) Å).
Parameter
Characteristic
Molecular formula
Molecular weight
Space group
C38H24O8PÀuFeRe2
1264.76
–
P1
The bridging ferrocenylacetylide ligand in complex 3
forms a σ-bond with the Re(1) atom (Re(1)—C(9),
2.056(4) Å) and a π-bond with the Re(2) atom
(Re(2)—C(9), 2.319(4) Å; Re(2)—C(10), 2.390(5) Å).
For comparison, the corresponding distances in the
σ,π-phenylacetylide ligand in dirhenium complexes 5 and
Re2(µ-C≡CPh)(µ-CH=CH2)(CO)5(µ-Ph2PCH2PPh2)7
Temperature/K
a/Å
b/Å
c/Å
110
10.915(1)
12.962(1)
13.679(2)
109.436(2)
103.165(2)
92.157(2)
1763.5(3)
2
α/deg
β/deg
γ/deg
V/Å3
Z
are 2.11(2), 2.29(2), 2.40(2)
Å
and 2.09(2),
2.34(1), 2.48(2) Å, respectively. In cluster 3, the
C(10)—C(9)—Re(1)—Au(1)—Re(2) fragment is planar
to within 0.03 Å. The C(9)—C(10) distance in complex
3 (1.225(7) Å) is somewhat larger than the C≡C distance
(1.200(9) Å) in the σ-acetylide ligand in the complex
Re2(µ-H)(σ-C≡CPh)(CO)7(µ-Me2PCH2PMe2)7 due,
probably, to π-coordination. The corresponding C≡C
distances in complexes 5 and 6 are 1.18(3) and 1.23(1) Å,
respectively.4,6 However, it should be noted that
virtually no elongation of the C≡C bond in the
σ,π-acetylide ligand (1.201(8) Å) was observed in the
cluster Os3(µ-H)(µ-C≡CPh)(CO)9(PMe2Ph).8
–3
dcalc/g cm
2.382
Diffractometer
Radiation
µ/cm
2θmax/deg
Bruker SMART 1000 CCD
Mo-Kα (λ = 0.71073 Å)
153.13
–1
60
10190
Number of independent
reflections (Rint
)
(0.0313)
R1 (based on F for
reflections with I > 2σ(I ))
wR2 (based on F 2 for
all reflections)
0.0354
(8824 reflections)
0.0902
Number of parameters
in the refinement
460
The results of the present study provide additional
evidence that σ,π-coordination of the acetylide ligand in
bi- and polynuclear metal complexes can cause only
insignificant elongation of the C≡C bond, unlike the
σ,π,π-coordination, which may lead to substantial elon-
gation of this bond. For example, the C≡C bond length
in complex 2 is 1.32(2) Å.3
The red-brown fraction was additionally purified by chro-
matography. Red crystals of complex 4 (10 mg) were obtained
by crystallization. IR (CH2Cl2), ν(CO)/cm–1: 2010 v.s, 1997 v.s,
1992 v.s, 1933 s, 1916 m. 1H NMR (CDCl3), δ: 4.16 (s, 5 H,
C5H5); 4.55 (t, 2 H, C5H4, J = 2.0 Hz); 4.98 (t, 2 H, C5H4,
J = 2.0 Hz); 7.40—7.60 (m, 15 H, C6H5). 31P NMR (CDCl3),
δ: 90.41 (s).
Experimental
X-ray diffraction study of cluster 3. A single crystal of
complex 3 suitable for X-ray diffraction study was obtained by
crystallization from a hexane—CH2Cl2 mixture. The atomic
coordinates were deposited with the Cambridge Structural
Database. The principal crystallographic characteristics are
given in Table 2. The X-ray data were processed using the
SAINT program.10 The empirical absorption correction was
applied based on repeated measurements of the intensities of
equivalent reflections (the SADABS program11). The structure
was solved by the direct method and refined by the full-matrix
least-squares method based on F 2 with anisotropic thermal
parameters for all non-hydrogen atoms. The H atoms were
placed in geometrically calculated positions and refined using
the riding model. All calculations were carried out with the use
of the SHELXTL-97 program package.12
The 1H and 31P NMR spectra were recorded on a Bruker
AMX-400 spectrometer (400.13 and 161.98 MHz, respec-
tively; 25 °C). The IR spectra were measured on a Bruker
IFS-113v instrument. The reactions were carried out in an
atmosphere of argon. The chromatographic separation was
performed in air. Silica gel L200/280 µm (Chemapol) and
Sorbfil chromatographic plates were used for the preparative
chromatographic separation of the reaction products. The
Re2(CO)8(NCMe)2 complex was synthesized from Re2(CO)10
according to a procedure described previously.9
Reaction of Re2(CO)8(NCMe)2 with Au(C≡CFc)PPh3.
A mixture of Re2(CO)8(NCMe)2 (90 mg, 0.133 mmol) and
Au(C≡CFc)PPh3 (90 mg, 0.133 mmol) in toluene (40 mL) was
refluxed for 20 min. The solvent was evaporated and two major
fractions (orange and red-brown) were isolated from the resi-
due by chromatography. The orange fraction was additionally
purified by preparative TLC. Orange crystals of the complex
Re2(µ-C≡CFc){Au(PPh3)}(CO)8 (3) were obtained by crystal-
lization from a hexane—CH2Cl2 mixture; the yield was 130 mg
(77%). IR (CH2Cl2), ν(CO)/cm–1: 2091 v.w, 2062 m, 2001 v.s,
1966 s, 1938 s. 1H NMR (CDCl3), δ: 4.23 (s, 5 H, C5H5); 4.28
(t, 2 H, C5H4, J = 2.0 Hz); 4.58 (t, 2 H, C5H4, J = 2.0 Hz);
7.40—7.60 (m, 15 H, C6H5). 31P NMR (CDCl3), δ: 82.01 (s).
This study was financially supported by the Russian
Foundation for Basic Research (Project Nos. 00-03-
32861 and 00-03-32807).
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Received July 18, 2001;
in revised form September 28, 2001