Preparation of (η5-RC5H4)2Mo 2(CO)2(μ-PhS)2 (R=H, MeCO) by the reaction of [η5-RC5H4Mo(CO)2]2 with (μ-PhS)2Fe<su

Article abstract of DOI:10.1016/s0020-1693(96)05412-6

Reaction of MoMo triply bonded complexes [η⁵-RC₅H₄Mo(CO)₂]₂ with the Fe/S butterfly compound (μ-PhS)₂Fe₂(CO)₆ in refluxing xylene gives two corresponding Mo=Mo doubly

Full text of DOI:10.1016/s0020-1693(96)05412-6

Inorganica Chimica Acta 256 (1997) 129–135
Note
Preparation of (h5-RC5H4)2Mo2(CO)2(m-PhS)2 (RsH, MeCO) by the
reaction of [h5-RC5H4Mo(CO)2]2 with (m-PhS)2Fe2(CO)6.
Crystal structures and acetyl transformation reactions of two isomers
trans/anti- and trans/syn-(h5-MeCOC5H4)2Mo2(CO)2(m-PhS)2
U
Li-Cheng Song a, , Ji-Quan Wang a, Qing-Mei Hu a, Ru-Ji Wang b, Thomas C.W. Mak c
a Department of Chemistry, Nankai University, Tianjin 300071, China
b Department of Chemistry, Tsinghua University, Beijing 100084, China
c Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
Received 14 February 1996; revised 14 June 1996
Abstract
Reaction of Mo^Mo triply bonded complexes [h5-RC5H4Mo(CO)2]2 with the Fe/S butterfly compound (m-PhS)2Fe2(CO)6 in refluxing
xylene gives two corresponding Mo_Mo doubly bonded complexes (h5-RC5H4)2Mo2(CO)2(m-PhS)2. Each of the complexes consists of
two isomers, namely trans/anti and trans/syn, in terms of the relative arrangement of the RC5H4 and CO ligands and the mutual orientation
of the phenyl groups on the bridging sulfur atoms. The two isomers with RsMeCO are convertible to each other in xylene at reflux and have
been crystallographically determined by X-ray diffraction. Further reactions of the RsMeCO complex with NaBH4 and MeMgI afford two
corresponding functional hydroxyl derivatives [h5-MeCH(OH)C5H4]2Mo2(CO)2(m-PhS)2 and [h5-Me2C(OH)C5H4]2Mo2(CO)2(m-
PhS)2.
Keywords: Multiple bond complexes; Molybdenum complexes; Crystal structures; Substituted cyclopentadienyl complexes
2. Results and discussion
1. Introduction
2.1. Reaction of [h5-RC5H4Mo(CO)2]2 with
(m-PhS)2Fe2(CO)6
It is well-known that the reactions of triply bonded com-
plexes R2M2(CO)4 (Rsparent and substituted cyclopenta-
dienyl; MsCr, Mo, W) with a variety of organic and
inorganic substrates have been studied extensively [1–3].
However, up to now only a few studies are involved in the
reaction of R2M2(CO)4 with the Fe/S cluster complex (m-
S2)Fe2(CO)6 [4–8] and no report has appeared concerning
the reaction of R2M2(CO)4 with Fe/S cluster complexes (m-
RS)2Fe2(CO)6. In order to compare the difference in reac-
tivities of R2M2(CO)4 toward (m-S2)Fe2(CO)6 and
(m-RS)2Fe2(CO)6, and to prepare Mo2Fe2 mixed clusters
containing both organic thiolato RS and functionally substi-
tuted cyclopentadienyl ligands, we initiated this study and
now report the interesting results.
The reaction of equimolar [h5-RC5H4Mo(CO)2]2
(RsH, MeCO) with (m-PhS)2Fe2(CO)6 was carried out in
xylene. Initially, it was found that the reaction did not occur
below 1308C; however at about 1408C for 3 h, TLC showed
no starting materials left and precipitates formed. After sol-
vent was removed, the residue was extracted with CH2Cl2,
and further subjected to TLC separation. From the residue
obtained by reaction of [h5-RC5H4Mo(CO)2]2 (RsH)
with (m-PhS)2Fe2(CO)6, a mixture of two isomers (trans/
anti- and trans/syn-Cp2Mo2(CO)2(m-PhS)2 (1a) and
(1b)) was first isolated, from which isomer trans/syn-
Cp2Mo2(CO)2(m-PhS)2 (1b) was separated and purified by
TLC. Since isomer 1a was well characterized previously [9]
an effort to isolate it was not made. From the residue obtained
by reaction of [h5-RC5H4Mo(CO)2]2 (RsMeCO) with
U Corresponding author.
0020-1693/97/$17.00 q 1997 Elsevier Science S.A. All rights reserved
PII S0020-1693(96)05412-6

130
L.-C. Song et al. / Inorganica Chimica Acta 256 (1997) 129–135
based on trans/cis arrangement of RC5H4 and carbonyl
ligands and anti/syn orientation of phenyl groups with
respect to the Mo2S2 ring. However, as mentioned above,
from the reactions of [h5-RC5H4Mo(CO)2]2 (RsH,
MeCO) with (m-PhS)2Fe2(CO)6 only two isomers, trans/
anti and trans/syn, were produced. The others which all have
RC5H4 and carbonyl ligands in cis positions were not
obtained. This fact suggested that the cisisomersareprobably
unstable and may convert into trans isomers easily under the
reaction conditions [10,11].
2.2. Structures of trans/anti- and trans/syn-
(h5-MeCOC5H4)2Mo2(CO)2(m-PhS)2 (2a and 2b)
In order to unambiguously confirm the structures of 2a and
2b, X-ray analyses were undertaken. The molecular struc-
tures of 2a and 2b are shown in Figs. 1 and 2, respectively.
Atomic coordinates and equivalent isotropic temperaturefac-
tors, and selected bond lengths and angles are listed in
Scheme 1.
(m-PhS)2Fe2(CO)6 two isomers trans/anti- and trans/syn-
(h5-MeCOC5H4)2Mo2(CO)2(m-PhS)2 (2a) and (2b) were
separated and purified by TLC, respectively (Scheme 1). So,
in contrast to our initial objective, the reaction did not give
the expected Mo2Fe2 mixed clusters; instead it yielded the
above dinuclear molybdenum complexes through an
exchange of RS ligands in (m-PhS)2Fe2(CO)6 with CO
ligands of [h5-RC5H4Mo(CO)2]2.
Although isomer 1a was previously prepared by another
route [9], isomers 1b, 2a and 2b are new compounds and
were characterized by elemental analysis, IR, 1H NMR and
MS spectroscopies. In the IR spectrum of1b twostrongbands
in the carbonyl region around 1900 cmy1 were assigned to
two trans carbonyls whereas in the 1H NMR spectrum of 1b
two peaks at d 5.25 and d 5.60 ppm were assigned to two
trans Cp rings and one peak at d 7.23 ppm was assigned to
two syn phenyl groups attached to the bridging sulfur atoms.
In addition the mass spectrum of 1b showed its parent ion
Mq at m/z 600. In the IR spectrum of 2a the Mo-carbonyls
belonging to the semi-bridging type (see Section 2.2)
showed one band at 1863 cmy1, while in that of 2b the Mo-
Fig. 1. Molecular structure of 2a.
carbonyls showed three bands in the range 1840–1950 cmy1
,
one belonging to semi-bridging and the others to terminal
(also see Section 2.2). The1HNMR spectrumof2aexhibited
only one single peak for methyl groups at d 2.03 ppm and
two sets of triplets for Cp rings appeared at d 5.40 and d 5.70
ppm, while that of 2b showed two single methyl peaks at d
1.95 and d 2.18 ppm and four sets of triplets for Cp rings
from d 5.40 to d 5.93 ppm. Although the mass spectra of 2a
and 2b did not show their molecular ion, the two isomers
showed reasonable fragment ions, such as Mqy2CO at
m/z 628.
In principle, for the compounds of the type (h5-
RC5H4)2Mo2(CO)2(m-PhS)2 five isomers are possible,
Fig. 2. Molecular structure of 2b.

L.-C. Song et al. / Inorganica Chimica Acta 256 (1997) 129–135
131
Table 1
Table 3
Atomic coordinates (=105 for Mo; =104 for others) and equivalent isotro-
pic temperature factors a (=104 for Mo and S; =103 for others) for 2a
Atomic coordinates (=105 for Mo; =104 for others) and equivalent isotro-
pic temperature factors a (=104 for Mo and S; =103 for others) for 2b
x
y
z
Ueq
x
y
z
Ueq
Mo(1)
S(1)
13030(7)
y1805(2)
2148(7)
1975(6)
1739(7)
2899(7)
1841(7)
2459(8)
3896(8)
4209(7)
2826(7)
3792(8)
y1820(7)
y1973(7)
y2041(8)
y1954(7)
y1803(7)
y1745(7)
46590(6)
5382(2)
8339(5)
5985(6)
6973(7)
4794(7)
3365(6)
2238(7)
2957(7)
4540(7)
6184(7)
7729(7)
7374(7)
8867(7)
10333(7)
10335(7)
8885(7)
7389(7)
39388(4)
3957(1)
4044(4)
64(4)
4062(5)
1750(5)
1950(5)
2752(6)
3081(6)
2463(5)
824(5)
340(1)
398(4)
65(1)
60(1)
45(1)
43(1)
46(1)
58(1)
60(1)
52(1)
46(1)
61(1)
40(1)
49(1)
54(1)
57(1)
52(1)
44(1)
Mo(1)
Mo(2)
S(1)
S(2)
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
20192(8)
21248(8)
1218(3)
3138(2)
5872(7)
y1742(7)
y373(10)
1663(8)
4461(10)
y237(9)
962(10)
2268(10)
1660(11)
y3(10)
y445(9)
960(12)
2552(13)
2866(9)
2407(10)
3653(11)
5287(11)
5736(10)
4526(10)
1727(8)
3583(9)
2228(9)
873(9)
9783(2)
17404(2)
1156(1)
1564(1)
764(2)
1665(2)
90(2)
2736(2)
861(2)
1664(2)
298(2)
296(2)
558(2)
729(2)
42130(6)
34111(6)
1941(2)
5683(2)
4281(6)
3463(6)
1705(7)
5419(6)
4237(7)
3511(7)
3862(8)
5094(8)
5880(8)
5155(8)
3903(8)
2694(10)
2743(11)
1249(7)
383(7)
353(2)
320(2)
403(6)
371(6)
73(1)
59(1)
98(1)
69(1)
49(1)
42(1)
53(1)
59(1)
60(1)
55(1)
51(1)
70(1)
110(1)
43(1)
52(1)
63(1)
61(1)
56(1)
50(1)
38(1)
41(1)
45(1)
42(1)
45(1)
65(1)
37(1)
57(1)
71(1)
65(1)
57(1)
46(1)
O(1)
O(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
838(6)
3176(5)
3790(5)
3122(5)
1838(6)
1214(6)
1872(5)
568(2)
65(3)
y180(3)
992(2)
652(2)
a Ueq defined as one third of the trace of the orthogonalized U tensor.
511(3)
700(3)
y157(8)
121(8)
947(8)
Table 2
1045(3)
1186(3)
2455(2)
2216(2)
2168(2)
2314(2)
2640(2)
2722(3)
1542(2)
1398(3)
1384(3)
1523(3)
1671(2)
1680(2)
˚
Selected bond lengths (A) and bond angles (8) for 2a
1500(7)
3456(7)
2698(7)
1699(7)
2158(7)
4315(7)
3776(8)
6483(7)
7738(8)
8422(9)
7871(9)
6627(8)
5922(7)
Mo(1)–Mo(1a)
Mo(1)–S(1a)
Mo(1)–Cp(1)
O(2)–C(7)
C(2)–C(6)
O(2)–C(7)
2.609(1) Mo(1)–S(1)
2.435(2) Mo(1)–C(1)
2.010(6) O(1)–C(1)
1.221(8) C(2)–C(3)
1.456(9) C(2)–C(7)
1.221(8) C(2)–C(3)
1.456(9) C(2)–C(7)
2.440(2)
1.936(5)
1.160(7)
1.408(8)
1.493(8)
1.408(8)
1.493(8)
835(10)
y1146(10)
5534(9)
6111(10)
7912(11)
9166(10)
8565(10)
6755(9)
C(2)–C(6)
Mo(1a)–Mo(1)–S(1)
Mo(1a)–Mo(1)–Cp(1) 166.0(1) Mo(1a)–Mo(1)–S(1a) 57.7(1)
57.6(1) Mo(1a)–Mo(1)–C(1)
79.6(1)
S(1)–Mo(1)–C(1)
C(1)–Mo(1)–S(1a)
S(1a)–Mo(1)–Cp(1)
Mo(1)–C(1)–O(1)
O(2)–C(7)–C(8)
89.0(2) S(1)–Mo(1)–S(1a)
79.9(2) S(1)–Mo(1)–Cp(1)
22.2(1) C(1)–Mo(1)–Cp(1)
173.7(4) O(2)–C(7)–C(2)
122.3(5) C(2)–C(7)–C(8)
109.5(2) Mo(1)–S(1)–Mo(1a)
116.3(2)
115.3(1)
120.4(1)
114.4(2)
117.9(5)
119.8(5)
64.7(1)
a Ueq defined as one third of the trace of the orthogonalized U tensor.
ularcenter of2aislocatedonacrystallographicinversecenter
(0, 0.5, 0.5). For 2a the two carbonyls attached to Mo(1)
and Mo(1a) are exactly identical and belong to semi-bridg-
ing, whose asymmetry parameter a [14] is 0.53. For 2b
carbonyl C(2)–O(2) is a semi-bridging (as0.44) and
C(1)–O(1) is a terminal. The results of structure analyses
for the carbonyls attached to molybdenum atoms are in good
agreement with those results from the IR data of 2a and 2b.
The Mo2S2 rings of the two isomers are all planar and their
crystallographic data are quite similar to those of the above
three known analogs [9,12,13]. In addition, the distances of
Mo(1)–S(1)–C(9)
C(9)–S(1)–Mo(1a)
Symmetry transformation: asyx, 1yy,1 yz).
Cp(1) is the center of the five-membered ring composed of C(2)–C(6)
atoms.
Tables 1–4. As seen from Figs. 1 and 2, the two isomers
consist of two h5-MeCOC5H4Mo(CO) fragmentsbridgedby
two phenylthiolato groups. Two substitutedcyclopentadienyl
and two carbonyl ligands of 2a and 2b are in trans positions;
however, the two phenyl groups of 2a lie in the anti positions
and those of 2b in the syn positions. Thus, 2a can be
represented as trans/anti-(h5-MeCOC5H4)2Mo2(CO)2-
(m-PhS)2 and 2b as trans/syn-(h5-MeCOC5H4)2Mo2-
(CO)2(m-PhS)2. The ligand orientations in these two iso-
mers have also been observed in two molybdenum analogs
trans/anti-Cp2Mo2(CO)2(m-PhS)2 [9] and trans/syn-
Cp2Mo2(CO)2(m-ButS)2 [9,12] and one tungsten analog
trans/anti-Cp2W2(CO)2(m-PriS)2 [13]. In fact, the molec-
˚
the Mo_Mo double bond of 2a (2.609(1) A) and 2b
(2.598(1) A) are almost the same and comparablewiththose
of the above two molybdenum analogs (2.616(2) A [9,12]
and 2.569(6) A [9], respectively).
˚
˚
˚
2.3. Reactions of a mixture of 2a and 2b with NaBH4 or
MeMgI
2a and 2b are the first of the Mo2S2 type of complexes with
organic functional groups on the cyclopentadienyl rings. In

132
L.-C. Song et al. / Inorganica Chimica Acta 256 (1997) 129–135
Table 4
order to explore the reactivity of 2a and 2b and to further
prepare other functional derivatives, we carried out the reac-
tions of a mixture of 2a and 2b with NaBH4 in methanol to
afford an isomeric mixture of 3a and 3b in 57% yield, and
with MeMgI in THF to give 4a and 4b in 44% yield, respec-
tively (Scheme 2). The new functional derivatives 3 and 4
were characterized by elemental analyses, IR and 1H NMR
spectroscopies. The IR spectra of 3 and 4 showed three
absorption bands assigned to the carbonyls attached to Mo
atoms in the region between 1930 and 1820 cmy1 and one
broad band centered at about 3430 cmy1 attributed to their
hydroxyl groups. It is worth noting that although the 1H NMR
spectra of 3 and 4 showed their respective organic groups,
such as the substituted cyclopentadienyls, hydroxyl groups
and phenyl groups, they were very complicated. This is
because both of them, on the one hand, contained two iso-
mers, namely trans/anti and trans/syn, and each of the iso-
mers (except 4a with a symmetric center), on the other hand,
is chiral and consists of a given number of stereomers, i.e. 3a
has 3 diastereomers (RR, RS, SS) and 3b has 4 diastereomers,
while 4b has a pair of enantiomers.
˚
Selected bond lengths (A) and bond angles (8) for 2b
Mo(1)–Mo(2)
Mo(1)–S(2)
Mo(1)–C(3)
Mo(1)–C(5)
Mo(1)–C(7)
Mo(2)–S(1)
Mo(2)–C(2)
Mo(2)–C(17)
Mo(2)–C(19)
Mo(2)–Cp(2)
O(2)–C(2)
2.598(1)
2.436(2)
2.312(7)
2.363(9)
2.279(7)
2.415(2)
1.926(8)
2.339(7)
2.348(8)
2.001(8)
1.175(9)
1.48(1)
1.211(9)
1.50(1)
1.41(1)
1.806(6)
1.38(1)
Mo(1)–S(1)
Mo(1)–C(1)
Mo(1)–C(4)
Mo(1)–C(6)
Mo(1)–Cp(1)
Mo(2)–S(2)
Mo(2)–C(16)
Mo(2)–C(18)
Mo(2)–C(20)
O(1)–C(1)
O(3)–C(8)
C(8)–C(9)
C(16)–C(21)
S(1)–C(10)
C(10)–C(15)
C(23)–C(24)
2.429(2)
1.961(8)
2.364(8)
2.319(9)
1.998(9)
2.420(2)
2.306(7)
2.383(8)
2.306(7)
1.15(1)
1.24(1)
1.47(1)
1.48(1)
1.794(9)
1.39(1)
1.38(1)
C(3)–C(8)
O(4)–C(21)
C(21)–C(22)
C(10)–C(11)
S(2)–C(23)
C(23)–C(28)
S(1)–Mo(1)–S(2)
S(2)–Mo(1)–C(1)
S(2)–Mo(1)–Cp(1)
S(1)–Mo(2)–S(2)
S(2)–Mo(2)–C(2)
S(2)–Mo(2)–Cp(2)
Mo(1)–C(1)–O(1)
Mo(1)–S(1)–Mo(2)
Mo(2)–S(1)–C(10)
Mo(1)–S(2)–C(23)
114.5(1)
89.9(2)
119.6(2)
115.6(1)
84.5(2)
122.9(2)
175.0(7)
64.9(1)
114.4(2)
112.6(2)
S(1)–Mo(1)–C(1)
S(1)–Mo(1)–Cp(1)
C(1)–Mo(1)–Cp(1)
S(1)–Mo(2)–C(2)
S(1)–Mo(2)–Cp(2)
C(2)–Mo(2)–Cp(2)
Mo(2)–C(2)–O(2)
Mo(1)–S(1)–C(10)
Mo(1)–S(2)–Mo(2)
Mo(2)–S(2)–C(23)
88.6(2)
120.8(2)
113.0(4)
82.1(2)
120.4(2)
112.7(4)
170.7(6)
113.0(2)
64.7(1)
2.4. Conversion reaction between 2a and 2b
Just like the experiments showed in Section 3.5, the trans
isomers 2a and 2b can convert mutually under the reaction
conditions (1408C, N2). According to the study on the iso-
merization of (m-RS)(m-R9S)Fe2(CO)6 [15], the mecha-
nism for this type of conversion might be that proposed in
Scheme 3.
116.3(3)
Cp(1) and Cp(2) are the centers of five-membered rings composed of
C(3)–C(7) and C(16)–C(20), respectively.
The mechanism involves that one of the Mo–S bonds
relaxes first to produce a transition state, in whichtwoorbitals
of the sulfur atom with lone electron pairs may overlap with
an empty d-orbital of the Mo atom, generated from the laxity
of the Mo–S bond. Then, further rotation around the other
Mo–S bond would accomplish this conversion. However, a
process, in which homolytic cleavage of the Ph–S bond (to
produce a phenyl and a bridging sulfur free radicals) and
recombination of the two free radicals (after the rotation
mentioned above) occur, should not be ruled out in the pro-
posed mechanism, since the conversions were carried out at
a temperature as high as 1408C.
3. Experimental
Scheme 2.
All reactions were performed under prepurified tank nitro-
gen using vacuum-line techniques. Xylene and THF were
distilled from Na/benzophenone ketyl under nitrogen. Meth-
anol was purged with nitrogen for 30 min prior to use. Pre-
parative TLC was carried out on glass plates (26=19 cm)
coated with silica gel G (10–40 mm). [h5-RC5H4Mo-
(CO)2]2 (RsH [16], MeCO [17], (m-PhS)2Fe2(CO)6
[18] and MeMgI [19] were prepared according to the liter-
ature. NaBH4 was used as purchased from commercialorigin.
IR spectra were recorded on Nicolet FT-5DX and MAGNA
Scheme 3.

L.-C. Song et al. / Inorganica Chimica Acta 256 (1997) 129–135
133
4
5
FT-750 infrared spectrophotometers. 1H NMR spectra were
recorded on Jeol FX 90Q and Bruker AC-P 200 NMR spec-
trometers. C/H analyses and MS determinations were per-
formed by a Perkin-Elmer 240C analyzer and HP 5988A
spectrometer, respectively. Melting points were determined
on a Yanaco MP-500 apparatus.
CH3), 5.40 (t, 2H, H3,H ), 5.82 (t, 2H, H2,H ); for the
other h5-MeCOC5H4, d 2.18 (s, 3H, CH3), 5.54 (t, 2H, H3,
H4), 5.93 (t, 2H, H2,H 5); d 7.20 (s, 10H, 2C6H5) ppm. MS
(EI, 98Mo), m/z (relative intensity): 628 [(My2CO)q,
2.8], 530 [(My2Ph)q, 1.3], 474 [(My2COy2Ph)q,
1.3], 410 [(MeCOC5H4)2Mo2q, 1.5], 388 [(C5H4)2-
Mo2S2q, 0.9], 260 [(Mo2S2)q, 1.2], 196 [(Mo2)q, 0.6],
186 [(Ph2S)q, 2.3], 154 [(Ph2)q, 5.4], 77 (Phq, 25.6).
3.1. Reaction of Cp2Mo2(CO)4 with (m-PhS)2Fe2(CO)6
A 100 ml two-necked flask fitted with a magnetic stir-bar,
a rubber septum, and a reflux condenser topped with a nitro-
gen inlet tube was charged with 0.500 g (1.152 mmol) of
Cp2Mo2(CO)4, 0.574 g (1.152 mmol) of (m-PhS)2Fe2-
(CO)6 and 30 ml of xylene. The mixture was refluxed for 3
h. Solvent was removed under reduced pressure and the res-
idue was extracted with CH2Cl2. The extract was concen-
trated to ;10 ml and subjected to TLC separation on silica
gel glass plates (2:1 petroleum ether/CH2Cl2 as eluent) to
give a mixture of 1a and 1b with a ratio of 0.8:1. 1H NMR
(CDCl3): d 5.34 (s, 5H, C5H5), 5.49 (s, 10H, 2C5H5), 5.71
(s, 5H, C5H5), 7.32–7.48 (m, 20H, 4C6H5). The mixturewas
further separated and purified by TLC to give the dark brown
isomer 1b (30 mg, 4.4%); m.p. 2208C (dec.). Anal. Found:
C, 47.83; H, 3.55. Calc. for C24H20Mo2O2S2: C, 48.33; H,
3.3. Reaction of a mixture of 2a and 2b with NaBH4
A flask as above was charged with 0.200 g (0.294 mmol)
of a mixture of 2a and 2b, 0.050 g (1.321 mmol) of NaBH4
and 25 ml of methanol. The reaction mixture was stirred at
room temperature for 10 h. Similar work-up as above was
followed (but using 2:1 petroleum ether/acetone as eluent)
to give 0.115 g (57%) of 3 as a brown solid; m.p. 1208C
(dec.). Anal. Found: C, 49.55; H, 3.59. Calc. for
C28H28Mo2O4S2: C, 49.13; H, 4.12%. IR (KBr disk):
n(C^O) 1827(s), 1844(s), 1922(m); n(O–H) 3427
1
(broad) cmy1. H NMR (CDCl3): d 1.24–1.72 (m, 12H,
4CH3), 1.96 (s, 1H, OH), 2.18 (s, 2H, 2OH), 2.24 (s, 1H,
OH), 4.12–4.80 (m, 4H, 4CH), 4.96–6.08 (m, 16H, 4C5H4),
7.28 (s, 20H, 4C6H5) ppm (as a trans/anti and trans/syn
mixture).
3.38%. IR (KBr, disk): n(C^O) 1835(s), 1909(vs) cmy1
.
1H NMR (CDCl3): d 5.25 (s, 5H, C5H5), 5.60 (s, 5H, C5H5),
7.23 (s, 10H, 2C6H5) ppm. MS (EI, 98Mo), m/z (relative
intensity): 600 (Mq, 5.2), 544 [(My2CO)q, 31.1], 390
[(My2COy2Ph)q, 34.2], 326 [(Cp2Mo2)q, 12.4], 260
[(Mo2S2)q, 9.1], 196 [(Mo2)q, 6.4], 186 [(Ph2S)q, 9.0],
163 [(CpMo)q, 5.1], 154 [(Ph2)q, 12.4], 98 (Moq, 4.0),
77 (Phq, 40.0).
3.4. Reaction of a mixture of 2a and 2b with MeMgI
In the flask described above, a mixture of 2a and 2b (0.200
g, 0.294 mmol) was dissolved in 20 ml of THF. Then, 5 ml
(2.47 mol/l, 12.35 mmol) MeMgI/Et2O were added slowly
into the flask under stirring. Afterstirringatroomtemperature
for 12 h, 5 ml of saturated aqueous NH4Cl solution were
added. The resulting mixture wasevaporatedtodrynessunder
vacuum and the residue was extracted with CH2Cl2. Extract
was concentrated to ;10 ml and subjected to TLC separation
using 6:1 benzene/ether as eluent. A greenish brown band
was collected to give 0.092 g (44%) of 4 as a brown solid;
m.p. 130–1318C. Anal. Found: C, 50.12; H, 4.19. Calc. for
C30H32Mo2O4S2: C, 50.56; H, 4.53%. IR (KBr, disk):
n(C^O) 1827(vs), 1852(vs), 1909(s); n(O–H) 3443
3.2. Reaction of [h5-MeCOC5H4Mo(CO)2]2 with
(m-PhS)2Fe2(CO)6
A flask as above was charged with 1.00 g (1.93 mmol) of
[h5-MeCOC5H4Mo(CO)2]2, 0.96 g (1.93 mmol) of (m-
PhS)2Fe2(CO)6 and 30 ml of xylene. The mixture was
refluxed for 3 h. The work-up similar to that of 1b was
followed, but using 6:1 benzene/ether as eluent. A greenish
yellow band, 2a (34 mg, 2.8%), and a dark brown band, 2b
(40 mg, 3.3%), were obtained. 2a: m.p. 228–2298C. Anal.
Found: C, 48.81; H, 3.50. Calc. for C28H24Mo2O4S2:C,
49.42; H, 3.55%. IR (KBr, disk): n(C_O) 1671(s);
n(C^O) 1863(vs) cmy1. 1H NMR (CDCl3): d 2.03 (s, 6H,
2CH3), 5.45 (t, 2H of 2C5H4), 5.70 (t, 6H of 2C5H4), 7.10–
7.45 (m, 10H, 2C6H5) ppm. MS (EI, 98Mo), m/z (relative
intensity): 628 [(My2CO)q, 3.3], 530 [(My2Ph)q,
1.3], 474 [(My2COy2Ph)q, 1.4], 410 [(MeCOC5H4)2-
Mo2q, 1.3], 260 [(Mo2S2)q, 1.2], 186 [(Ph2S)q, 3.9],
154 [(Ph2)q, 6.9], 77 (Phq, 28.3). 2b: m.p. 208–2108C.
Anal. Found: C, 49.45; H, 3.28. Calc. for C28H24Mo2O4S2;
C, 49.42; H, 3.55%. IR (KBr, disk): n(C_O) 1665(s),
1678(s); n(C^O) 1849(vs), 1908(s), 1942(m) cmy1. 1H
NMR (CDCl3): for one of h5-MeCOC5H4, d 1.95 (s, 3H,
1
(broad) cmy1. H NMR (CDCl3): d 1.17–1.92 (m, 24H,
8CH3), 2.00 (s, 2H, 2OH), 2.21 (s, 1H, OH), 2.60 (s, 1H,
OH), 4.65–5.92 (m, 16H, 4C5H4), 7.24 (s, 20H, 4C6H5)
ppm (as a trans/anti and trans/syn mixture).
3.5. Conversion reaction between 2a and 2b
A 50 ml two-necked flask fitted with a magnetic stir-bar, a
rubber septum, and a reflux condenser topped with a nitrogen
inlet tube was charged with 11 mg of 2a and 10 ml of xylene.
Then the solution was refluxed for 10 h. Solvent wasremoved
in vacuum and 5 ml of CH2Cl2 were added. The solution was
subjected to TLC separation using 6:1 benzene/ether as
eluent to give 2 mg of 2a and3mgof
2b.

134
L.-C. Song et al. / Inorganica Chimica Acta 256 (1997) 129–135
Table 5
Details of crystal parameters, data collections and structure refinements for isomers 2a and 2b
2a
2b
Crystal parameters
Molecular formula
Molecular weight
Color and habit
Crystal size (mm)
Crystal system
C28H24Mo2O4S2
680.48
C28H24Mo2O4S2
680.48
dark red needle
0.05=0.05=0.10
triclinic
dark brown plate
0.02=0.10=0.10
monoclinic
P21/n (No. 14)
7.1912(3)
31.9151(7)
10.9926(6)
90.00
#
Space group
P1 (No. 2)
˚
a (A)
7.6931(8)
8.1241(8)
10.8700(9)
87.642(7)
71.831(7)
88.323(4)
644.8(3)
14
˚
b (A)
˚
c (A)
a (8)
b (8)
109.54(1)
90.00
2618.2(8)
g (8)
3
˚
V (A )
Z
Density (calc.) (g cmy3
F(000)
)
1.752
340
1.17
1.726
1360
1.15
Absorption coefficient, m (mmy1
)
Data collection
Diffractometer
Rigaku R-AXIS IIR imaging plate
Temperature (8C)
Radiation
1
21"12
"1
˚
graphite-monochromatized Mo Ka, ls0.71073 A
200=200
Imaging plate size (mm2)
2umax (8)5
200=200
Unique reflections measured
2438
5018
Rint
0.031
0.050
Refinement
No. observations, n
No. variables, p
2187 (NFoNG6s(NFoN)
164
3563 (NFoNG6s(NFoN)
326
1yexp[y(sin u/l)2]
1
Weight scheme, w
s2(NF N)
s2(NF N)q0.0003NFoN
2
o
o
RFs8NNFoNyNFcNN/8NFoN
0.049
0.053
1.14
0.22
0.051
wRs[8w(NFoNyNFcN)2/8wNFoN ]1/2
Ss[8w(NFoNyNFcN)2/(nyp)]1/2
Largest D/s in final cycle
0.059
1.63
0.21
y0.88, 0.70
2
y3
˚
Largest peak in final difference map (e A
)
y0.72, 1.07
Similarly, 2 mg of 2a and4mgof
24 mg of 2b were used as the starting material.
2b were obtained when
calculations. Cell reduction and data collection were per-
formed using R-AXIS softwares on a SGI work station, and
structure solution and refinement using SHELXTL PC [20]
on a PC 486 computer. Analytical expressions of atomic
scattering factors were employed, and anomalous dispersion
corrections were incorporated [21].
3.6. Structure determination of 2a and 2b
Suitable crystals of 2a and 2b for X-ray diffraction study
were obtained by slow evaporation of their CH2Cl2/hexane
solutions. Details of crystal parameters, data collections and
structure refinements of 2a and 2b are given in Table 5.
Since the single crystals of 2a and 2b are very small, the
intensity data were collected on a Rigaku R-AXIS II diffrac-
tometer with rotating anode source (50 kV, 150 mA) at room
temperature (294 K). Patterson superposition andsuccessive
difference Fourier syntheses yielded the positions of all non-
hydrogen atoms, which were subjected to anisotropic refine-
ment. All hydrogen atoms were generated geometrically(C–
Acknowledgements
We are grateful to the NationalNaturalScienceFoundation
of China and Special Foundation of State Education Com-
mittee of China for financial support of this work.
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