Reaction of dipropargyl phthalate with Co2(CO)8 and Mo2Cp2(CO)4 gives the di or tetranuclear clusters. The crystal structure of [C6H4-1,2-(CO2CH2C 2H-μ)2][Co2(CO)6]2

Article abstract of DOI:10.1016/S0277-5387(99)00022-4

The reaction of dipropargyl phthalate with Co₂(CO)₈ in benzene at room temperature gave a new cluster [C₆H₄-1,2-(CO₂CH₂C ₂H-μ)₂][Co₂(CO)₆]₂ 1, which reacts with the cyclopentadienyl tricarbonyl molybdenum anion [Mo(CO)₃Cp]^- to form the tetranuclear clusters [C₆H₄-1,2-(CO₂CH₂C ₂H-μ)₂][Co₂(CO)₆][CoMoCp(CO) ₅] 2 and [C₆H₄-1,2-(CO₂CH₂C ₂H-μ)₂] [CoMoCp(CO)₅]₂ 3, respectively. The reaction of Mo₂Cp₂(CO)₄ with dipropargyl phthalate gave rise to the formation of the dinuclear cluster [o-(HC₂CH₂OCO)C₆H₄(CO ₂CH₂C₂H-μ)][Mo₂Cp ₂(CO)₄] 4 and tetranuclear cluster [C₆H₄-1,2-(CO₂CH₂C ₂H-μ)₂] [Mo₂Cp₂(CO)₄]₂ 5, respectively. The cluster 4 reacted with Co₂(CO)₈ to produce the tetranuclear cluster [C₆H₄-1,2-(CO₂CH₂C ₂H-μ)₂][Co₂(CO)₆] [Mo₂Cp₂(CO)₄] 6. These clusters were characterized by C/H analyses, IR and ¹H NMR. The structure of [C₆H₄-1,2-(CO₂CH₂C ₂H-μ)₂][Co₂(CO)₆]₂ 1 and [o-(HC₂CH₂OCO)C₆H₄ (CO₂CH₂C₂H-μ)][Mo₂Cp ₂(CO)₄]-CH₂Cl₂ 4·CH₂Cl₂ were determined by single crystal X-ray diffraction methods. Elsevier Science Ltd.

Full text of DOI:10.1016/S0277-5387(99)00022-4

Polyhedron 18 (1999) 1555–1560
Reaction of dipropargyl phthalate with Co2(CO)8 and Mo2Cp2(CO)4
gives the di or tetranuclear clusters. The crystal structure of
[C6H4-1,2-(CO2CH2C2H-m)2][Co2(CO)6]2 and
[o-(HC2CH2OCO)C6H4(CO2CH2C2H-m)][Mo2Cp2(CO)4]–CH2Cl2
b
Xue-Nian Chena, Jie Zhanga, Er-Run Dinga, Yuan-Qi Yina , , Jie Sun
*
aState Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences,
Lanzhou 730000, People’s Republic of China
bShanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, People’s Republic of China
Received 28 October 1998; received in revised form 4 January 1999
Abstract
The reaction of dipropargyl phthalate with Co2(CO)8 in benzene at room temperature gave a new cluster [C6H4-1,2-(CO2CH2C2H-
m)2][Co2(CO)6]2 1, which reacts with the cyclopentadienyl tricarbonyl molybdenum anion [Mo(CO)3Cp]2 to form the tetranuclear
clusters [C6H4-1,2-(CO2CH2C2H-m)2][Co2(CO)6][CoMoCp(CO)5] 2 and [C6H4-1,2-(CO2CH2C2H-m)2] [CoMoCp(CO)5]2 3, respec-
tively. The reaction of Mo2Cp2(CO)4 with dipropargyl phthalate gave rise to the formation of the dinuclear cluster [o-
(HC2CH2OCO)C6H4(CO2CH2C2H-m)][Mo2Cp2(CO)4] 4 and tetranuclear cluster [C6H4-1,2-(CO2CH2C2H-m)2] [Mo2Cp2(CO)4]2 5,
respectively. The cluster 4 reacted with Co2(CO)8 to produce the tetranuclear cluster [C6H4-1,2-(CO2CH2C2H-m)2][Co2(CO)6]
[Mo2Cp2(CO)4] 6. These clusters were characterized by C/H analyses, IR and 1H NMR. The structure of [C6H4-1,2-(CO2CH2C2H-
m)2][Co2(CO)6]2 1 and [o-(HC2CH2OCO)C6H4 (CO2CH2C2H-m)][Mo2Cp2(CO)4]-CH2Cl2 4?CH2Cl2 were determined by single
crystal X-ray diffraction methods.
1999 Elsevier Science Ltd. All rights reserved.
Keywords: Crystal structure; Cobalt; Molybdenum; Cluster compounds
1. Introduction
actions. Herein we wish to report the capping reactions of
diyne ligands with dinuclear species and the exchange
reactions of the tetranuclear clusters with the metal ex-
change reagent Na[MoCp(CO)3]. The crystal structures of
the clusters [C6H4-1,2-(CO2CH2C2H-m)2][Co2(CO)6]2
Alkyne and alkynyl species bearing a C;C functional
group belong to a class of surface species which may play
a pivotal role in various catalytic reactions such as CO
hydrogenation, and the coordination chemistry of the
corresponding ligands has been studied extensively. [1,2]
The interaction of alkynyl compounds with dinuclear
species leading to adducts with a tetrahedral C2M2 core
has been recognized as one of the classical reactions in the
field of organometallic chemistry [3]. In recent years diyne
clusters have been receiving considerable attention because
of their unusual structures and reactions [4–8]. As an
extension, we examined the interaction of diynes with
dinuclear species and investigated the interrelations of two
C;CH or C2M2 during the capping and exchange re-
and
[o-(HC2CH2OCO)C6H4(CO2CH2C2H-m)][Mo2C-
p2(CO)4]?CH2Cl2 were determined by single crystal X-ray
diffraction methods.
2. Experimental
All reactions were carried out under a nitrogen atmos-
phere using standard Schlenk and vacuum line techniques.
The solvents were treated using the usual method for
preparing anhydrous and deoxygenated solvents. Column
chromatography was carried out using 160–200 mesh
silica gel. Mo(CO)6 were purchased from Aldrich Chem.
Co. Co2(CO)8 was prepared according to the literature
[28]. The dipropargyl phthalate was obtained by esterifica-
*Corresponding author. Tel.: 186-931-8827971-37; fax: 186-931-
8417088.
E-mail address: hcom@ns.lzb.ac.cn (Y.-Q. Yin)
0277-5387/99/$ – see front matter
PII: S0277-5387(99)00022-4
1999 Elsevier Science Ltd. All rights reserved.

1556
X.-N. Chen et al. / Polyhedron 18 (1999) 1555–1560
tion of phthalic anhydride with propargyl alcohol and
characterized by C/H analyses, IR and H NMR. The IR
spectra were recorded on a Nicolet FT-IR 10 DX spec-
trophotometer. The 1H NMR spectra were measured on
Bruker Am 300 MHz spectrometer. The C/H analyses
were performed on a Carlo Erba 1106 type analyzer.
clusters 4 and 5. Cluster 4 was recrystallized from hexane–
CH2Cl2 at 2208C to give red crystals 4?CH2Cl2 (280 mg,
37%). Anal. Calcd. for C29H22O8Mo2Cl2: C, 45.75; H,
2.91. Found: C, 45.72; H, 2.90. IR (KBr): n (C=O) 1745
m, 1725 m; n (CO) 1993 vs, 1909 vs, (terminal CO) and
1
1
1828 vs (semi-bridge CO) cm21. H NMR (CDCl3): d
7.78–7.54 (m, 4H, C6H4), 5.91 (s, 1H, CH), 5.37 (s, 2H,
CH2), 5.32 (s, 10H, 2Cp), 4.93 (d, 2H, CH2, J52.5 Hz)
and 2.54 (t, 1H, ;CH, J52.5 Hz) ppm.
2.1. Preparation of 1
The dipropargyl phthalate (242 mg, 1 mmol) was treated
with Co2(CO)8 (684 mg, 2 mmol) in benzene (40 cm3) at
room temperature. After being stirred for 2 h, the solvent
was removed under reduced pressure and the residue
purified by chromatography on silica gel using benzene as
an eluent. Recrystallization from hexane–benzene gave red
prismatic crystals (648 mg, 79.6%). Anal. calcd. for
C26H10O16Co4: C, 38.36; H, 1.24. Found: C, 38.38; H,
1.20. IR (KBr): n (C=O) 1737 m, 1715 m; n (CO) 2098 s,
The cluster 5 was recrystallized from hexane–CH2Cl2 at
2208C to give a red oil (208 mg, 19%). Anal. Calcd. for
C42H30O12Mo4: C, 45.42; H, 2.72. Found: C, 45.51; H,
2.65. IR (KBr): n (C=O) 1742 m, 1728 m; n (CO) 1990
vs, 1905 vs (terminal CO) and 1830 vs (semi-bridge CO)
1
cm21. H NMR (CDCl3): d 7.80–7.56 (m, 4H, C6H4),
5.80 (s, 2H, 2CH), 5.38 (s, 4H, 2CH2), 5.29 (m, 20H, 4Cp)
ppm.
2055 vs, 2022 vs, 2016 vs, 2002 vs (terminal CO) cm21
.
2.4. Preparation of 6
1H NMR (CDCl3): d 7.81–7.57 (m, 4H, C6H4), 6.14 (s,
2H, 2CH) and 5.52 (s, 4H, 2CH2) ppm.
The cluster 4 (150 mg, 0.2 mmol) was treated with
Co2(CO)8 (70 mg, 0.2 mmol) in benzene (20 cm3) at
room temperature. After stirred for 2 h, the solvent was
removed in reduced pressure and the residue purified by
chromatography on silica gel using benzene as an eluent.
Recrystallization from hexane–CH2Cl2 at 2208C to give a
red solid cluster 6 (130 mg, 68%). Anal. Calcd. for
C34H20O14Mo2Co2: C, 42.44; H, 2.10. Found: C, 42.42;
H, 2.08. IR (KBr): n (C=O) 1734 m, 1718 m; n (CO) 2099
vs, 2058 vs, 2025 vs, 1918 s (terminal CO) and 1839 vs
2.2. Preparation of 2 and 3
The Mo(CO)6 (132 mg, 0.5 mmol) was added to a
solution of 89 mg (0.5 mmol) NaCp–DME in THF (30
cm3). The mixtures were heated under reflux for 20 h and
cooled to room temperature. Then 200 mg (0.25 mmol)
cluster 1 was added and the mixture was stirred for 60 h at
room temperature. The solvent was removed under vac-
uum. The residue was chromatographed on silica gel using
benzene–CH2Cl2 (1:1) as an eluent to give two red
fractions clusters 2 and 3. Cluster 2 was recrystallized from
hexane–CH2Cl2 at 2208C to give red crystals (70 mg,
32%). Anal. Calcd. for C30H15O15MoCo3: C, 40.57; H,
1.70. Found: C, 40.61; H, 1.66. IR (KBr): n (C=O) 1736
m, 1720 m; n (CO) 2098 s, 2056 vs, 2028 vs, 1944 s, 1890
1
(semi-bridge CO) cm21. H NMR (CDCl3): d 7.78–7.56
(m, 4H, C6H4), 6.06 (s, 1H, CH), 5.85 (s, 1H, CH), 5.42 (s,
4H, 2CH2), 5.32 (s, 10H, 2Cp) ppm.
2.5. Single crystal structure determination of 1 and 4?
CH2Cl2
1
m (terminal CO) cm21. H NMR (CDCl3): d 7.80–7.54
(m, 4H, C6H4), 6.06 (s, 1H, CH), 5.70 (s, 1H, CH), 5.42 (s,
4H, 2CH2), 5.33 (s, 5H, Cp) ppm.
Crystals suitable for an X-ray diffraction analysis were
obtained by recrystallization from hexane–CH2Cl2 and
mounted on glass fibers tip onto a goniometer. Diffraction
measurements were made on a Rigaku AFC7R diffrac-
tometer with graphite monochromated Mo-Ka radiation
The cluster 3 was recrystallized from hexane–CH2Cl2 at
2208C to give a red solid (52 mg, 22%). Anal. Calcd. for
C34H20O14Mo2Co2: C, 42.44; H, 2.10. Found: C, 42.38;
H, 2.15. IR (KBr): n (C=O) 1738 m, 1724 m; n (CO) 2097
˚
(l50.71069 A) and a 12 kW rotating anode generator.
s, 2058 vs, 2000 vs, 1945 s, 1892 m (terminal CO) cm21
.
Unit cells were determined and refined by a least-squares
method using 23 reflections in the range 13.39,2u,
21.408 for 1 and 18 reflections in the range 14.96,2u,
21.688 for 4?CH2Cl2. The data were collected at a
temperature of 20618C using the v22u scan technique.
The structure of each compound was solved by direct
methods and expanded using the Fourier technique. The
non-hydrogen atoms were refined anisotropically. Hydro-
gen atoms were included but not refined. Neutral atom
scattering factors were taken from Cromer and Waber. All
calculations were performed using the TEXSAN crystallo-
graphic software package of the Molecular Structure
Corporation.
1H NMR (CDCl3): d 7.80–7.52 (m, 4H, C6H4), 5.70 (s,
2H, 2CH), 5.42 (s, 4H, 2CH2), 5.32 (s, 10H, 2Cp) ppm.
2.3. Preparation of 4 and 5
A solution of [Mo2Cp2(CO)6] (490 mg, 1 mmol) in
toluene (30 cm3) was refluxed for 14 h. Upon cooling to
room temperature, the dipropargyl phthalate (242 mg, 1
mmol) was added and the mixtures were stirred for another
3 h at room temperature. The solvent was removed under
vacuum. The residue was chromatographed on silica gel
using benzene–CH2Cl2 as eluent to give two red fractions

X.-N. Chen et al. / Polyhedron 18 (1999) 1555–1560
1557
3. Results and discussion
bonded complex [Mo2Cp2(CO)4], prepared by refluxing a
toluene solution of the metal–metal single bonded dimer
[Mo2Cp2(CO)6] [15], the dinuclear cluster [o-
(HC2CH2OCO)C6H4(CO2CH2C2H-m)] [Mo2Cp2(CO)4] 4
and tetranuclear cluster [C6H4-1,2-(CO2CH2C2H-m)2]
[Mo2Cp2(CO)4]2 5 are obtained. Further reaction of 4 with
Co2(CO)8 in THF at room temperature produce the cluster
6. These reactions described in this work are summarized
in Scheme 1.
The reaction of dipropargyl phthalate with Co2(CO)8 in
benzene at room temperature gave the cluster [C6H4-1,2-
(CO2CH2C2H-m)2][Co2(CO)6]2 1. The exchange regent
Na[MoCp(CO)3], prepared by refluxing a THF solution of
NaCp and Mo(CO)6 [9–14], was reacted in situ with the
cluster 1 at room temperature for 60 h to give two
tetranuclear
clusters
[C6H4-1,2-(CO2CH2C2H-
and [C6H4-1,2-
m)2][Co2(CO)6][CoMoCp(CO)5]
(CO2CH2C2H-m)2][CoMoCp(CO)5]2 3. Through the in
situ reaction of dipropargyl phthalate with the triply
2
The reaction (2) required a long time at room tempera-
ture, but at high temperature (refluxing THF) the reactant
decomposes and the expected product could not be ob-
Scheme 1.

1558
X.-N. Chen et al. / Polyhedron 18 (1999) 1555–1560
tained. These are inconsistent with the exchange reaction
of the RCCo3(CO)9 clusters [16–19].
the methylene (CH2) connected to the C;CH group and
the proton of uncoordinated terminal alkyne (C;CH).
These data are consistent with the structure of 4, which is
produced by the coordination of a Mo2Cp2(CO)4 group to
one of the two C;C bonds and does not affect coordina-
tion to the other C;C bond. It is worth pointing out that
the chemical shift of the proton attached to the C2Co2
cores appeared at lower fields than that of the proton
connected to the C2Mo2 cores. This is consistent with the
literature [20,21].
The configurations of isomer clusters 3 and 6 could be
deduced from their IR and 1H NMR spectra. The IR
spectrum of cluster 3 did not exhibit a signal due to a
semi-bridging carbonyl but the IR spectrum of the clus-
ter 6 shows a semi-bridging carbonyl at 1830 cm21. Be-
cause the semi-bridging carbonyl occurs in the
In the IR spectra of clusters 4, 5 and 6, besides the
terminal carbonyls absorption bands exhibited in the range
2099–1905 cm21, there are absorption bands at around
1830 cm21 characteristic of bridging carbonyls. The IR
spectra of clusters 1, 2 and 3 show only the terminal
carbonyls in the range 2098–1890 cm21. In clusters 1–6,
there are two absorption bands in the range 1745–1715
cm21 characteristic of carbonyls of the ester group of the
ligands.
1
In the H NMR spectra of all clusters 1–6, a singlet at
about d55.32 arises from the protons of the cyclopen-
tadienyl ring (C5H5) and singlets at d55.52–5.32 arise
from the two or four protons of the methylene (CH2)
connected C–CH group. The protons of the coordinated
terminal alkyne (C–CH) appear in the region d56.14–
5.70, as expected [4,14,15]; because of the reduction in the
C;C triple-bond character there is a downfield shift in the
position of these terminal protons with respect to the free
ligand (d52.50). It is important to note that the chemical
shift of coordinated terminal alkyne (C–CH) is affected by
the nature of the metal coordinated to C–CH group. These
protons appear in the range d56.14–6.06 when the C–CH
group is coordinated to Co–Co in clusters 1, 2 and 6 and
appear in the range d55.91–5.80 when the C–CH group is
coordinated to Mo–Mo in clusters 4, 5 and 6. However,
they appear at d55.70 when the C–CH group is coordi-
C2Mo2(C5H5)2(CO)4,
C2W2(C5H5)2(CO)4
and
C2MoW(C5H5)2(CO)4 cores and does not occur in the
C2CoMo(C5H5)(CO)5 core [14,22–26], it could be con-
sidered that cluster 3 possesses two C2CoMo(C5H5)(CO)5
cores and cluster 6 possesses one C2Co2(CO)6 core and
1
one C2Mo2(C5H5)2(CO)4 core. In the H NMR spectra,
the two protons of two C2H groups of cluster 3 appear
with the same chemical shift at d55.70. This illustrates
that two protons occur in the same chemical environment.
However, the two protons of the two C2H groups of cluster
6 appear as two singlets at d56.06 and 5.85, respectively.
1
Comparing with the H NMR spectra of cluster 1 (C2H
1
nated to Co–Mo in clusters 2 and 3. The H NMR spectra
coordinated to Co–Co, d56.14) and clusters 4 and 6 (C2H
coordinated to Mo–Mo, d55.91 and 5.85), the singlet at
d56.06 is assignable to the protons of the C2H group
of cluster 4, besides the above signals, exhibited a doublet
at d54.93 and a triplet at 2.54 assigned to the protons of
Table 1
Crystallographic parameters for 1 and 4?CH2Cl2
Clusters
1
4?CH2Cl2
a
Formula
C26H10O16Co4
814.06
Monoclinic
P21 /a
8.521(2)
29.143(6)
12.918(7)
C28H20O8Mo2 –CH2Cl2
Formula weight
Crystal system
Space
761.27
Triclinic
P-1
˚
a (A)
10.964(3)
12.941(3)
10.859(2)
93.29(2)
92.81(2)
107.67(2)
1462.1(6)
2
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
100.12(3)
3
˚
V (A )
3158(2)
4
1.712
1608.00
21.37
20.0
Z
Dcal (g cm23
F(000)
)
1.729
756.00
10.88
m(Mo-Ka) (cm21
Temp. (8C)
)
20.0
Scan type
2umax (8)
v22u
51.0
v22u
49.9
No. of reflections
Measured
Total: 5610
Total: 4204
Unique: 5194 (Rint50.028)
3151 (I.2.00s (I))
455
Unique: 3912 (Rint50.017)
3234 (I.2.50s (I))
370
No. observations
No. variables
Residuals: Rb; Rbw
0.044; 0.048
0.029; 0.037
a A unit cell contained the two 4 and two CH2Cl2.
b R5(ouuF8uuFcuu)/ouF8u, Rw5[ow(F8u2uFcu)2 /owF28 ]1 / 2
.

X.-N. Chen et al. / Polyhedron 18 (1999) 1555–1560
1559
Fig. 1. Molecular structure of cluster 1.
coordinated to Co–Co and at d55.85 to the protons of the
C2H group coordinated to Mo–Mo. All these are con-
sistent with the configurations of isomers of clusters 3 and
6.
In order to further establish the structures of 1–6, single
crystal structure determinations of 1 and 4?CH2Cl2 were
undertaken using X-ray diffraction methods. Table 1 lists
their crystallographic data. The selected bond lengths and
angles are given in Table 2 for 1 and Table 3 for 4?
CH2Cl2, respectively. Fig. 1 and Fig. 2 show the molecu-
lar structures of the 1 and 4 clusters, respectively.
As seen in Fig. 1, a Co2(CO)6 unit coordinates to each
of the two alkynyl groups of dipropargyl phthalate. The
C2Co2 core adopts a pseudo-tetrahedral geometry. The
overall conformations of the two (CH2CCH)Co2(CO)6
moieties in 1 resemble each other. The two Co–Co bond
Table 2
˚
Selected bond lengths (A) and angles (8) for 1
Co(1)–Co(2) 2.472(1)
Co(1)–C(7) 1.951(6)
Co(3)–Co(4) 2.475(1)
Co(3)–C(19) 1.956(6)
Co(1)–C(8) 1.955(6)
Co(3)–C(20) 1.937(7)
Co(2)–C(7) 1.937(6)
Co(4)–C(19) 1.937(7)
Co(2)–C(8) 1.942(6)
Co(4)–C(20) 1.926(7)
C(7)–C(8) 1.319(8)
C(19)–C(20) 1.317(9)
C(14)–C(15) 1.36(1)
C(11)–C(12) 1.403(8)
Co(2)–Co(1)–C(7) 50.3(2)
Co(2)–Co(1)–C(8) 50.4(2)
C(7)–Co(1)–C(8) 39.5(2)
Co(1)–Co(2)–C(7) 50.8(2)
Co(1)–Co(2)–C(8) 50.8(2)
C(7)–Co(2)–C(8) 39.8(2)
C(7)–C(8)–C(9) 140.9(6)
C(8)–C(7)–H(1) 141(4)
Co(4)–Co(3)–C(19) 50.2(2)
Co(4)–Co(3)–C(20) 50.0(2)
C(19)–Co(3)–C(20) 39.6(3)
Co(3)–Co(4)–C(19) 50.9(2)
Co(3)–Co(4)–C(20) 50.3(2)
C(19)–Co(4)–C(20) 39.9(3)
C(18)–C(19)–C(20) 143.3(6)
C(19)–C(20)–H(10) 140(3)
Table 3
˚
Selected bond lengths (A) and angles (8) for 4?CH2Cl2
Mo(1)–Mo(2) 2.9811(5)
Mo(1)–C(16) 2.171(4)
Mo(1)–C(15) 2.194(4)
Mo(2)–C(15) 2.126(4)
Mo(2)–C(16) 2.202(4)
C(15)–C(16) 1.348(6)
C(21)–C(22) 1.365(8)
C(19)–C(24) 1.391(6)
C(27)–C(28) 1.134(7)
Mo(2)–C(4) 1.965(5)
Mo(2)–Mo(1)–C(15) 45.4(1)
C(15)–Mo(1)–C(16) 36.0(2)
Mo(1)–Mo(2)–C(16) 46.6(1)
Mo(1)–C(15)–C(16) 71.1(2)
C(15)–C(16)–C(17) 135.3(4)
C(16)–C(15)–H(11) 138.6
Mo(2)–Mo(1)–C(16) 47.5(1)
Mo(1)–Mo(2)–C(15) 47.3(1)
C(15)–Mo(2)–C(16) 36.2(2)
Mo(2)–C(16)–C(15) 68.8(3)
C(26)–C(27)–C(28) 179.2(6)
C(27)–C(28)–H(20) 168.6
Fig. 2. Molecular structure of cluster 4?CH2Cl2.

1560
X.-N. Chen et al. / Polyhedron 18 (1999) 1555–1560
˚
lengths are 2.472(1) and 2.475(1) A, the Co–C bond
distances in the C2Co2 cores are in the range 1.926(7)–
Acknowledgements
˚
1.956(6) A comparable with those of related dicobalt
complexes [4,27]. The C(7)–C(8) and C(19)–C(20) dis-
tances are 1.319(8) and 1.317(9) A, respectively, in the
This work was supported by the Laboratory of Or-
ganometallic Chemistry, Shanghai Institute of Organic
Chemistry, Chinese Academy of Sciences.
˚
normal region of m-alkyne–hexacarbonyldicobalt com-
pounds. The bond angles C(7)–C(8)–C(9), H(1)–C(7)–
C(8), C(18)–C(19)–C(20) and H(10)–C(20)–C(19) are
140.9(6), 141(4), 143.3(6) and 140(3)8, respectively.
These data also lie in the normal range [4,27].
References
As seen in Fig. 2, the overall conformations of the
(C;CH)Mo2Cp2(CO)4 moieties are quite similar to those
previously described for [h5-C5H5Mo(CO)2]2(m-C2H2)
[24]. The C2Mo2 core adopts a pseudo-tetrahedral geome-
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Raithby, M.E. Robson, D.A. Wilkinson, J. Chem. Soc. Dalton Trans.
(1992) 3171.
˚
try. The Mo(1)–Mo(2) bond length is 2.9811(5) A and the
˚
C(15)–C(16) bond length is 1.348(6) A, respectively. The
Mo–C bond lengths in the C2Mo2 cores are in the range
[5] K. Onitsuku, XinQung Tao, WenQing Wang, Y. Otsuka, K.
Sonogashira, T. Adachi, T. Yoskida, J. Organomet. Chem. 473
(1994) 195.
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12 (1993) 1365.
[7] M.G. Karpov, S.P. Tunik, V.R. Denisov, G.L. Starova, A.B. Nikol-
skii, F.M. Dolgushin, A.I. Yanovsky, Yu.T. Struchkov, J. Or-
ganomet. Chem. 485 (1995) 219.
[8] Y. Rubin, C.B. Knobler, F. Diederich, J. Am. Chem. Soc. 112
(1990) 4966.
[9] F. Richter, H. Vahrenkamp, Chem. Ber. 15 (1982) 3224.
[10] F. Richter, H. Vahrenkamp, Angew. Chem., Int. Ed. Engl. 20 (1981)
98.
[11] F. Richter, H. Vahrenkamp, Angew. Chem. 92 (1980) 66.
[12] F. Richter, H. Vahrenkamp, Angew. Chem., Int. Ed. Engl. 19 (1981)
65.
[13] D.M. Macomber, M.D. Rauch, J. Organomet. Chem. 258 (1983)
331.
[14] S.-L. Wu, E.-R. Ding, Y.-Q. Yin, J. Sun, J. Organomet. Chem. 570
(1998) 71.
[15] H. Adams, L.J. Gill, M.J. Morris, Organometallics 15 (1996) 4182.
[16] H. Beurich, H. Vahrenkamp, Angew. Chem. 93 (1981) 128.
[17] R. Blumhofer, F. Richter, H. Vahrenkamp, Chem. Ber. 119 (1986)
194.
[18] H.-P. Wu, Y.-Q. Yin, X.-Y. Huang, K.-B. Yu, J. Organomet. Chem.
498 (1995) 119.
[19] H.-P. Wu, Z.-Y. Zhao, S.-M. Liu, Y.-Q. Yin, Polyhedron. 15 (1996)
4117.
[20] B. Happ, T. Bartik, C. Zucchi, M.C. Rossi, F. Ghelfi, G. Palyi, G.
Varadi, G. Szalontai, I.T. Horvath, A. Chiesi-Villa, C. Guastini,
Organomet. 14 (1995) 809.
[21] N. Berre-Cosquer, R. Kergoat, J. Organomet. Chem. 427 (1992)
325.
[22] S.D. Jensen, B.H. Robinson, J. Simpson, Organometallics 5 (1986)
1690.
[23] L.-C. Song, J.-Y. Shen, Q.-M. Hu, B.-S. Han, R.-J. Wang, H.-G.
Wang, Inorg. Chim. Acta. 219 (1994) 93.
˚
2.202(4)–2.126(4) A. These data are comparable to the
corresponding values in [h5-C5H5Mo(CO)2]2(m-C2H2)
[24].
˚
The C(15)–C(16) distance of 1.348(6) A is longer than
the C(27)–C(28) distance of 1.134(7) A. The bond angles
˚
C(15)–C(16)–C(17) and C(16)–C(15)–H are 135.3(4)
and 138.68, in contrast with the C(26)–C(27)–C(28) angle
of 179.2(6)8 and the C(27)–C(28)–H angle of 168.68.
These differences in bond distances and angles between
the two alkynyl groups are due to the coordination of the
Mo2Cp2(CO)4 group.
The conformations of the phenyl groups showed a
contradiction between 1 and 4. The C(21)–C(22) distance
˚
of 1.365(8) A is very close to that of the C(19)–C(14)
˚
distance of 1.391(6) A in cluster 4; however, the C(11)–
˚
C(12) distance of 1.403(8) A is longer than the C(14)–
˚
C(15) distance of 1.36(1) A in cluster 1. The differences in
the bond lengths are likely to depend on the effect of the
two large coordinated CO2CH2C2Co2(CO)6 groups.
Finally, it was found, through structural analysis of the
carbonyls attached to the metal atoms, that the carbonyl
C(4)–O(4) bonded to Mo(2) is a linear semi-bridging
carbonyl. The values for judging the type of carbonyl
C(4)–O(4) fall in the range typical for linear semi-bridg-
ing carbonyls [24–26], i.e. O(4)–C(4)–Mo(2)5169.7(4)8,
C(4)–Mo(2)–Mo(1)568.6(1)8, a50.48 [calculated from
˚
˚
Mo(2)–C(4)51.965(6) A, Mo(1) . . . C(4)52.911(5) A].
Thus, the structural analysis of 4 provides a reasonable
explanation for its IR spectrum having one band at a
frequency as low as 1830 cm21
.
[24] W.I. Bailey Jr., M.H. Chisholm, F.A. Cotton, L.A. Rankel, J. Am.
Chem. Soc. 100 (1978) 5764.
[25] R.J. Klingler, W.M. Butler, M.D. Curtis, J. Am. Chem. Soc. 100
(1978) 5034.
Supplementary data
[26] M.D. Curtis, K.R. Han, W.M. Butler, Inorg. Chem. 19 (1980) 2096.
[27] R.S. Dickson, P.J. Fraser, Adv. Organomet. Chem. 12 (1974) 323.
[28] R.B. King, in: Organometallic Syntheses: Transition-Metal Com-
pounds, Vol. 1, Academic Press, New York, London, 1965, p. 98.
Supplementary data are available from the CCDC, 12
Union Road, Cambridge CB2 1EZ, UK, on request (CCDC
deposition numbers 105636 and 105638).