New ligand substitution modes of M2(μ-SR)2(CO)8 (M=Mo, W; R=alkyl, aryl): Synthesis, structure and properties of new di-nuclear metal(I) carbonyl thiolates, [M2(μ-SPh)2(CO)xLy]n- (M=Mo, W; X=6, 8; Y=0, 1; L=PhS, (Ph)2PCH2P(Ph)2 and S2CNEt2; N=1, 0)

Article abstract of DOI:10.1016/S0022-328X(01)01173-1

Reaction of [M₂(SC₆H₅)₂(CO)₈] (M=Mo, W) with NaSR (SR=SC₆H₅, S₂CNEt₂) in the presence of tetra-alkylammonium halide, or with diphenylphosphinemethane (DPPM=(C₆H₅)₂P CH₂P (C₆H₅)₂) in certain solvents affords new dinuclear metal(I)-carbonyl thiolates, [W₂(SC₆H₅)₂(CO)₈] (1), [Et₄N][Mo₂(SC₆H₅) ₃(CO)₆] (2), [Bu₄N][Mo₂(SC₆ H₅)₂(CO)₆(S₂CNEt₂)] (3), [W₂(SC₆H₅)₂(CO)₆DPPM] (4) and polymer [W₂(SC₆H₅)₂(CO)₆ DPPM]_m (5). The crystal structures of 1,2,3 and 4 reveal that 1 contained a planar [W₂S₂] unit, 2 had a [Mo₂S₃] core with a planar Mo₂S₂ unit coordinated by a third SC₆H₅ bridging ligand and 3 and 4 possessed a planar [M₂S₂] (M=Mo, W) core with two M atoms in different coordination environments. Three ligand substitution modes in the complexes were found: (i) substitution took place on the two M atoms in cis-direction resulting in three bridging ligand compound (for 2); (ii) substitution occurred on one metal atom leading to unsymmetrical M₂S₂ unit (for 3 and 4); and (iii) substitution occurred on the two M atoms in trans-direction to form a polymer (for 5). IR, NMR and CV of these complexes were measured. An existence of mixed valence metal atoms leading to charge transfer and alteration of electrochemical behavior for the complexes were discussed and the possible structure of polymer compound 5 was proposed.

Full text of DOI:10.1016/S0022-328X(01)01173-1

Journal of Organometallic Chemistry 640 (2001) 127–139
www.elsevier.com/locate/jorganchem
New ligand substitution modes of M2(m-SR)2(CO)8 (M=Mo, W;
R=alkyl, aryl): synthesis, structure and properties of new
di-nuclear metal(I) carbonyl thiolates, [M2(m-SPh)2(CO)xLy]n−
(M=Mo, W; x=6, 8; y=0, 1; L=PhS, (Ph)2PCH2P(Ph)2 and
S2CNEt2; n=1, 0) and a polymer
[W2(m-SPh)2(CO)6(Ph)2PCH2P(Ph)2]m
Botao Zhuang *, Haofen Sun, Guohua Pan, Lingjie He, Qiang Wei, Zhangfen Zhou,
Saiqun Peng, Kechen Wu
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences,
P.O. Box 143, Fuzhou, Fujian 350002, China
Received 29 May 2001; accepted 28 July 2001
Abstract
Reaction of [M2(SC6H5)2(CO)8] (M=Mo, W) with NaSR (SR=SC6H5, S2CNEt2) in the presence of tetra-alkylammonium
halide, or with diphenylphosphinemethane (DPPM=(C6H5)2P CH2P (C6H5)2) in certain solvents affords new dinuclear metal(I)-
carbonyl thiolates, [W2(SC6H5)2(CO)8] (1), [Et4N][Mo2(SC6H5)3(CO)6] (2), [Bu4N][Mo2(SC6H5)2(CO)6(S2CNEt2)] (3),
[W2(SC6H5)2(CO)6DPPM] (4) and polymer [W2(SC6H5)2(CO)6 DPPM]m (5). The crystal structures of 1, 2, 3 and 4 reveal that 1
contained a planar [W2S2] unit, 2 had a [Mo2S3] core with a planar Mo2S2 unit coordinated by a third SC6H5 bridging ligand and
3 and 4 possessed a planar [M2S2] (M=Mo, W) core with two M atoms in different coordination environments. Three ligand
substitution modes in the complexes were found: (i) substitution took place on the two M atoms in cis-direction resulting in three
bridging ligand compound (for 2); (ii) substitution occurred on one metal atom leading to unsymmetrical M2S2 unit (for 3 and
4); and (iii) substitution occurred on the two M atoms in trans-direction to form a polymer (for 5). IR, NMR and CV of these
complexes were measured. An existence of mixed valence metal atoms leading to charge transfer and alteration of electrochemical
behavior for the complexes were discussed and the possible structure of polymer compound 5 was proposed. © 2001 Published
by Elsevier Science B.V.
Keywords: Substitution mode; Mo2S2-unit; W2S2 unit; Crystal structures; Spectroscopy and electrochemistry
formation [2,3]. Decarbonylation of [M2(m-SR)2-
1. Introduction
(CO)8]2−,0 and the subsequent reaction of its core
[M2S2] have attracted our attention because it may be
useful for synthesizing a variety of multi-metal com-
plexes that might contribute to understanding certain
aspects of metal-enzymes. In order to investigate the
reactivity of the [M2S2] unit in the complexes, a series of
ligand substituted dinuclear complexes such as the
MeCN or PPh3-substituted compound, [Mo2(SPh)2-
(CO)6(MeCN)2] and [Mo2(SPh)2(CO)6(PPh3)2] [4], ace-
tate-substituted complexes, [Mo2(SPh)2(CO)6(RCOO)]−
[5,6], [{Mo2(SPh)2(CO)6}2(OOCCH2CH2COO)2]2− [7],
In 1984, thiolate ligands were reacted with Mo(CO)6
(M=Mo, W) resulting in di-nuclear carbonyl com-
plexes containing thiolate bridges, [M2(m-SR)2(CO)8]2−
(M=Mo, W; R=Ph, But) with a planar [M2S2] core
[1]. These carbonyl complexes undergo reversible two-
electron oxidation accompanied by metalꢀmetal bond
* Corresponding author. Fax: +86-591-3714946.
E-mail address: zbt@ms.fjirsm.ac.cn (B. Zhuang).
0022-328X/01/$ - see front matter © 2001 Published by Elsevier Science B.V.
PII: S0022-328X(01)01173-1

128
B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
halide-substituted compounds, [Mo2(SPhCl)2(CO)6Br]−
[8], [Mo2(SPh)2(CO)6I]− [9] and the DPPM substituted
compound [Mo2(SPh)2(CO)6DPPM]− [10] have been
isolated and preliminarily investigated. The structure
determinations indicate that there were three ligand
substitution modes in these complexes. (i) The substitu-
tion may take place on the two M atoms with the
substituting ligands on the different sides of the planar
M2S2-unit, for example in MeCN-substituted com-
pound, the so-called trans-substitution mode A; (ii) the
substitution occurred on two metal atoms with the
bidentate substituting ligand located at the same side of
the planar M2S2-unit, as in acetate-substituted com-
pounds, the so-called cis-substitution mode B; (iii) the
substitution may occur on two M atoms by a mono-
dentate bridging ligand, as in the halide-substituted
compounds, the so-called bridge-forming substitution
mode C. Recently we have obtained a thiolate-substi-
tuted Mo complex, [Et4N][Mo2(SPh)3(CO)6] (2), as a
new example of bridge-forming substitution mode C.
Two other ligand-substituted Mo(W) thiolate carbonyl
complexes, [Bu4N][Mo2(SPh)2(CO)6(S2CNEt2)] (3) and
[W2(SPh)2(CO)6(DPPM)] (4), have been discovered that
adopt an unsymmetrical substitution mode D in which
ligand-substitution has occurred on one M atom.
Herein
formed on a CARLD ERBA instrumentation elemental
analyzer MOD 1106; 13C- and 95Mo-NMR spectra were
measured on a Varian-Unity-500 NMR spectrometer
with a solution of 2 M Na2MoO4 in D2O sealed in a
capillary (for 95Mo-NMR measurement) as reference.
For comparison, the 13C- and 95Mo-NMR spectra of
the compound [Mo2(SPh)2(CO)8] were also measured.
Cyclic voltammetry (CV) measurements were per-
formed with
a three-electrode cell using 0.1 M
Bu4NBF4 as the supporting electrolyte and acetone as
solvent. The working electrode was glass carbon (A=
0.0804 cm2), the reference electrode was an aqueous
SCE separated from the sample solution by a salt
bridge and the auxiliary electrode was platinum wire.
Solutions were deoxygenated and blanketed with a
nitrogen atmosphere and the potentiostat was a CV-B
from BAS (Bioanalytical Systems).
2.2. Synthesis of [W2(SPh)2(CO)8] (1)
A mixture of [Et4N]2[W2(SR)2(CO)8] [12] (4.43 g, 4.1
mmol) and I2 (1.05 g, 4.1 mmol) in 30 ml of CCl4 was
stirred at room temperature (r.t.) for 4 h. After filtering
off the white residue, a dark green filtrate was concen-
trated to a volume of 5 ml by vacuum. To the concen-
trated filtrate was added 20 ml MeOH and 2.2 g of
dark green micro-crystalline product [W2(SPh)2(CO)8]
(1) which was obtained by filtration. The precipitate
was washed with MeOH and dried in vacuum, yield
63%. Elemental Anal. Calc. for C18H10O8S2W2: C, 29.6;
H, 1.2; S, 7.9; W, 45.4. Found: C, 29.9; H, 1.6; S, 7.6;
W, 46.2%. IR (KBr Pellet): 2031s, 1963s and 1939s
cm−1 (wCO).
we report the synthesis, structure and spectroscopic
characterization of new metal(I) thiolate carbonyl com-
pounds: [W2(SPh)2(CO)8] (1), [Et4N][Mo2(SPh)3(CO)6]
(2), [Bu4N][Mo2(SPh)2(CO)6(S2CNEt2)] (3), [W2(SPh)2-
(CO)6(DPPM)] (4) and [W2(SPh)2(CO)6(DPPM)]m (5),
and the possible structure of polymer complex
[W2(SPh)2(CO)6(DPPM)]m (5). Different substitution
modes leading to change of configuration and differing
electrochemical behavior of M2S2 unit in these com-
plexes were also discussed.
2.3. Synthesis of [Et4N][Mo2(SPh)3(CO)6] (2)
A mixture of 0.08 g (0.61 mmol) NaSPh and 0.12 g
(0.72 mmol) Et4NCl in MeCN was stirred at 40 °C
overnight, then filtered. To the filtrate was added 0.3 g
(0.47 mmol) [Mo2(SPh)2(CO)8], and the resulting mix-
ture was stirred at 40 °C for another 24 h resulting in
red brown solution. This red brown solution was con-
centrated to 10 ml under vacuum, and then 20 ml
MeOH was added. After cooling to 4 °C overnight,
0.24 g (0.29 mmol) of black microcrystalline 2 was
obtained by filtration. The product was washed with
MeOH and dried under vacuum. Yield, 48% (based on
the amount of NaSPh used). Anal. Calc. for
C32H35Mo2NO6S3: C, 47.0; H, 4.3; N, 1.7; S, 11.7.
Found: C, 47.1; H, 4.3; N, 1.8; S, 11.5%. IR (KBr
pellet): 1998m, 1965s, 1940s, 1917s, 1849s cm−1
(wMoCꢀO), 608m, 579m, 507m, 498m cm−1 (lMoꢀCꢀO),
370w, 351m (wMoꢀC) and 433sh, 419m cm−1 (wMoꢀS).
The single crystals suitable for X-ray crystallography
were grown from the mixed solvents of MeCN/MeOH.
2. Experimental
2.1. Materials and methods
All experiments were carried out under nitrogen at-
mosphere using standard Schlenk techniques and all
solvents and reagents were dried and degassed before
use. The compound [Mo2(SPh)2(CO)8] was prepared
from [Et4N]2[Mo2(CO)8(SR)2] reacting with I2 accord-
ing to the literature methods [11]. IR spectra were
recorded on a Nicolet-Magna 750 Fourier transform IR
spectrometer or Digilab FTS-20E/D-V Fourier trans-
form IR spectrometer. Elemental analysis was per-

B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
129
2.4. Synthesis of [Bu4N][Mo2(SPh)2(CO)6(S2CNEt2)] (3)
W, 35.8% showed that the atom ratio was
C:H:P:S:W::43:32:2:2:2. Product 5 is almost insoluble
in CCl4, MeCN, benzene, toluene, acetone and
methanol, and is slightly soluble in CH2Cl2, Me2SO,
cyclohexane and hexane.
1. 0.634 g (1 mmol) of [Mo2(SPh)2(CO)8] were dis-
solved in 20 ml of acetone resulting in dark green
solution, after which 0.322 g (1 mmol) Bu4NBr was
added. The resulting solution was stirred at 50 °C
for half an hour then cooled to r.t. After adding
0.17 g (1 mmol) of NaS2CNEt2, the reaction mixture
was stirred at r.t. for 12 h and the resulting red–
brown solution was reduced to 10 ml under vacuum
and filtered. To the filtrate was added 20 ml of
isopropanol. After filtering off a small amount of
residue and cooling at 4 °C for several days, 0.5 g
of dark brown micro-crystalline product, [Bu4N]-
[Mo2(SPh)2(CO)6(S2CNEt2)] (3), was obtained by
filtration, washed with isopropanol and dried in
vacuum, yield, 52%. Elemental Anal. Calc. for
C59H56N2Mo2O6S4: C, 48.4; H, 5.8; N, 2.9. Found:
C, 48.3; H, 5.9; N, 2.9%. IR (KBr pellet): 2017s,
1928s, 1898s and 1799s (wMoCꢀO).
2. To a solution of [Bu4N][Mo2(SPh)2(CO)6Br] [9] (0.4
g, 0.5 mmol) in acetone (20 ml) was added 0.085g
(0.5 mmol) of NaS2CNEt2. The resulting mixture
was stirred at 50 °C for half an hour and at r.t. for
another 12 h. The red–brown solution was concen-
trated to 10 ml and then filtered. To the filtrate was
added 20 ml of isopropanol. After filtering off a
small amount of precipitate and cooling at 4 °C for
2.7. X-ray crystal structure determination
The crystal data and experimental conditions are
given in Table 1. All the samples were mounted on the
glass fiber and coated with epoxy cement. The intensi-
ties of 1, 2 and 4·1/2 C7H8 were collected on an Enraf-
Nonius CAD4 computer controlled kappa axis
diffractometer. A total of 2513 (for 1), 3454 (for 2) and
7734 (for 4·1/2 C7H8) were collected. Lorentz and po-
larization corrections were applied to the data. An
empirical absorption correction (base on a series of
psi-scans) was applied to the data. Relative transmis-
sion coefficients ranged from 0.663 to 0.998 (for 1),
0.949 to 1.000 (for 2) and 0.654 to 0.999 (for 4·1/
2 C7H8). The structures of 1 and 2 were solved by direct
methods with MOLTAN-83 program. A total of two
atoms were located from an E-map prepared from the
phase set with probability statistics: absolute figure of
merit=1.04 (for 1), 1.02 (for 2) and residual=5.82 (for
1), 8.67 (for 2). The structure of 4·1/2 C7H8 was solved
using Patterson heavy-atom method which revealed the
heavy atoms. The remaining atoms were located in
succeeding difference Fourier syntheses. Hydrogen
atoms were located and added to the structure factor
calculations but their positions were not refined. The
structures were refined using full-matrix least-squares
where the function minimized was ꢀ w(ꢁFoꢁ−ꢁFcꢁ)2 and
the weight w is defined as w=Fo/43.27 if FoB43.27 or
w=43.27/Fo if Fo]43.27 and w=w2 if w]0.10, w=
0.0 if wB0.10 (for 1); and as per the Killean and
Lawrence method with terms of 0.010 and 1.0 [13] (for
1 and 4·1/2 C7H8). The final cycle of refinement
converged with unweighted and weighted agreement
factors of R1=ꢀ ꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀ ꢁFoꢁ and Rw=
[ꢀ w(Fo−Fc)2/ꢀ wF2o]1/2. All the calculations were per-
formed by using MolEN/PC [14]. The data collection of
3 was performed on a Siemens Smart CCD diffrac-
tometer with graphite–monochromatic Mo–Ka radia-
tion. A total of 9146 refractions were collected and the
data reductions were performed on a silicon graphics
computer station with SMART CCC software. The struc-
ture of 3 was solved by conventional direct methods
several days,
a
dark brown micro-crystalline
product was collected, which was recognized as 3 by
its IR spectrum.
2.5. Synthesis of [W2(SPh)2(CO)6DPPM] (4)
A mixture of 0.40 g (0.5 mmol) of [W2(SPh)2(CO)8]
(1) and 0.19 g (0.5 mmol) of DPPM in 20 ml of toluene
was stirred at r.t. for 24 h resulting in green brown
solution. The resulting solution was concentrated to 10
ml by vacuum and 20 ml of methanol was added. 0.95
g of green product [W2(SPh)2(CO)6DPPM] (4)·1/2 C7H8
was obtained by filtration, washed with MeOH and
dried in vacuum. Yield: 81.4%. Elemental Anal. Calc.
for C43H32O6P2S2·1/2 C7H8: C, 47.1; H, 3.0; P, 5.2; S,
5.4. Found: C, 47.2; H, 3.2; P, 5.0; S, 5.5%. IR (KBr
pellet): 2033(m), 1956(s), 1925(s) and 1840(m) cm−1
.
2.6. Synthesis of polymer [W2(SPh)2(CO)6DPPM]m (5)
A mixture of 0.40 g (0.5 mmol) of [W2(SPh)2(CO)8]
and 0.38 g (1.0 mmol) of DPPM in 25 ml of toluene
was stirred at r.t. for 24 h affording a dark green
precipitate. The dark green solid product 5 was isolated
by filtration, washed with toluene and dried in vacuum.
Yield: 0.45 g. IR (KBr pellet): 2006(w), 1979(s), 1927(s),
1896(s) and some characteristic absorption of DPPM
ligand. Elemental Anal.: C, 52.1; H, 3.6; P, 6.0; S, 6.1;
(SHELXTL) and was refined by the full-matrix least-
squares method on F2 data using a Silicon Graphics
INDY computer and local programs [15]. All non-hydro-
gen atoms were refined anisotropically; hydrogen atoms
were located at idealized positions and refined with
fixed isotropic thermal parameters. The final refinement
converged with unweighted and weighted agreement

130
B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
factors of R1=ꢀ ꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀ ꢁFoꢁ and wR2=
The metal(I)-complex [Mo2(SPh)2(CO)8] [11] reacted
with thiolate ligand PhS− resulting in a triply bridged
dinuclear Mo(I)-complex which was isolated as a te-
traethylammonium salt, [Et4N][Mo2(SPh)3(CO)8] (2).
This substitution reaction (Eq. (3)), like the reaction of
halide substituted complexes [8,9], adopts the bridge-
forming substitution mode C.
[ꢀ w(Fo2 −Fc2)2/ꢀ w(Fo2)2]1/2
.
3. Results and discussion
3.1. Synthesis of the complexes and ligand substitution
reaction
MeCN
“
[Mo2(SPh)2(CO)8]+[Et4N]SPh
[Mo2(SPh)3(CO)6]+2CO
[Et4N]
The complex [W2(SPh)2(CO)8] (1) was prepared as
the Mo-analog [Mo2(SPh)2(CO)8] [11] according to re-
action (Eq. (1)):
(3)
In contrast to −SPh, −S2CNEt2, reacted with
[Mo2(SPh)2(CO)8] in the presence of Bu4NBr affording
[Bu4N][Mo2(SPh)2(S2CNEt2)] (3), in which the
−S2CNEt2 ligand chelates one Mo atom leading to an
unsymmetrical Mo2S2 core in the molecule (Eq. (4)). In
this case, the reaction adopted a new substitution mode
giving unsymmetrical geometry D.
CCl
4
[Et4N]2[W2(SPh)2(CO)8]+I2 “ [W2(SPh)2(CO)8]
+2[Et4N]I
(1)
In Eq. (1), [Et4N]2[W2(SPh)2(CO)8] (no WꢀW bond)
underwent two-electron oxidation by I2 affording com-
plex 1 with creation of WꢀW bond. The choice of
solvents is very important, non-coordinating solvents
such as CCl4, toluene or hexane are suitable for prepar-
ing complex 1 in high yield. Coordinating solvents such
as MeCN, DMF and DMSO lead to the formation of
solvent substituted compounds (Eq. (2)).
[Mo2(SPh)2(CO)8]+NaS2CNEt2
Bu NBr
4
ꢀꢀꢀꢀꢁ [Bu4N][Mo2(SPh)2(CO)6S2CNEt2]+2CO (4)
−NaBr
Reaction of [W2(SPh)2(CO)8] (1) with DPPM unexpect-
edly formed an unsymmetrical substitution mode D
product, [W2(SPh)2(CO)6DPPM] (4), in contrast with
the Mo-analog, [Mo2(SPh)2(CO)6DPPM], which is a
[M2(SPh)2(CO)8]2− +I2
Solvent
ꢀꢀꢀꢁ [M2(SPh)2(CO)6(Solvent)2]+2G+2CO
(2)
Table 1
Crystallographic data and data collection parameters for complexes 1, 2, 3 and 4·1/2 C7H8
Compounds
1
2
3
4·1/2 C7H8
C46.5H36O6P2S2W2
1184.58
Triclinic
P−1
Empirical formula
Formula weight
Crystal system
Space group
C20H10O8S2W2
810.13
Monoclinic
P21/c
C32H35Mo2NO6S3
817.17
Monoclinic
CC
C39H56Mo2N2O6S4
968.98
Triclinic
P−1
Unit cell dimensions
,
a (A)
9.172(2)
12.045(2)
11.152(2)
19.951(4)
11.046(2)
17.721(2)
11.1489(4)
12.4039(4)
19.4625(4)
103.6410(10)
96.542(2)
114.1470(10)
2319
2
1.39
1000
7.63
11.108(2)
12.195(6)
16.247(9)
101.83(5)
85.03(2)
95.91(2)
2204
2
1.79
1146
55.4
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
111.58(2)
112.45(4)
3
,
1146
2
1.35
748
140.7
3609
4
1.50
1656
8.8
Z
Dcalc (g cm−3
F(000)
)
v(Mo–Ka) (cm−1
)
Diffractometer
Enraf-Nonius CAD4 Enraf-Nonius CAD4 Siemens Smart CCD
Enraf-Nonius
CAD4
2391
Mo–Ka (0.71073 A)
ꢀ–q
Temperature (°C)
Radiation
Scan type
2391
2391
2391
,
,
,
,
Mo–Ka (0.71073 A) Mo–Ka (0.71073 A) Mo–Ka (0.71073 A)
ꢀ–q
ꢀ–q
ꢀ–q
2qmax (°)
52.0
2026
145
0.032
0.033
0.82
50.0
2878
440
0.035
0.036
0.69
46.6
50.0
5093
524
0.053
0.064
0.50
No. of observations [I\3.0|(I)]
No. of variables (p)
R
Rw (or wR2)
Goodness-of-fit
6482 (F0\4.0|(F))
478
0.064
0.1455(wR2)
0.833
Maximum shift in final cycle
Largest peaks in final difference map (e A
0.01|
1.52(47)
0.48|
0.40(6)
0.98|
0.817
0.02|
1.73(22)
−3
,
)

B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
131
Scheme 1.
S2CNEt2 ligand. It is evident that according to its
elemental analysis data, IR spectrum and solubility, 5 is
different from 4 and might be a polymer of trans-sub-
stitution mode A product [4]. The acquirement of poly-
mer 5 is significant because it makes possible to connect
M2S2 units in different arrangements by using special
multi-dentate ligands.
cis-substitution mode B product [10]. It is worth point-
ing out that if the ratio of [W2(SPh)2(CO)8]:DPPM is
1:2, a less soluble DPPM-containing WꢀSꢀCO polymer
(5), which possesses an IR spectrum very different from
complex 4, is obtained in high yield.
So far the ligand substitution reactions of
[M2(SPh)2(CO)8] (M=Mo, W) can be summarized as
following Scheme 1.
It is worth pointing out that the axial MꢀCO bond
distances are longer than the equatorial ones in the
structure of [M2(CO)8(SPh)2] (M=Mo, W). This may
imply that the axial carbonyls are easier to substitute
than the equatorial carbonyls. Therefore, in the ligand
substitution reaction, the ligands always replace the
axial carbonyls first. In some cases, if the ligands have
large steric bulk, the replacement occurs at the equato-
rial position. For instance, complex 4, owing to the
larger stereo-hindrance of DPPM than the S2CNEt2
ligand in complex 3, undergoes substitution at equato-
rial positions, and complex 3 adopted substitution at
both axial and equatorial positions simultaneously (see
next section).
3.2. Structures of 1, 2, 3, 4 and possible structure of
polymer 5
The selected bond distances and angles of 1, 2, 3 and
4 are listed in Tables 2–5, respectively, and the struc-
tures of 1, 2, 3 and 4 are depicted in Figs. 1–4,
respectively.
All four complexes possess a planar M2S2-unit (M=
Mo or W) with small change of dimensions shown in
Table 6.
The structure of 1 (Fig. 1) is centro-symmetric with
the geometry around each W atom being a distorted
octahedron with four carbon atoms from carbonyls and
two sulfur atoms from two bridging SPh ligands. The
geometry of the W2S2 core is almost the same as that of
Mo2S2 unit in the Mo-analog, [Mo2(SPh)2(CO)8] [11].
Complex 2 is comprised of a cation Et4N+ and a
di-nuclear molybdenum anion with three thiolate
bridges, [Mo2(SPh)3(CO)6]−. As shown in Fig. 2, the
structure of the anion of 2 contains a [Mo2S3] core (E)
with a planar Mo2S2 unit. As is listed in Table 6, the
dimension of the Mo2S2 unit in 2 is contracted by
Interestingly, the reaction of [Mo2(SPh)2(CO)6Br]−
with S2CNEt−2 ligand did not result in cis-substitution
mode B product [Mo2(CO)6(m-SPh)2(m-S2CNEt2)]− but
rather in the unsymmetrical substitution mode D
product, complex 3. The two phenyl rings of SPh−
ligands in 3 are trans-relative to the Mo2S2 plane in
contrast with [Mo2(SPh)2(CO)6Br]− in which the two
phenyl rings are cis [8]. This means that the reaction is
not a simple substitution of Br bridge by S2CNEt−2 , but
involves dissociation of the Br− bridge, a change of the
arrangement of phenyl rings and coordination of
,
,
0.01 A of MoꢀS, 0.08 A of MoꢀMo and 2.23° of
MoꢀSꢀMo than that in [Mo2(SPh)2(CO)8], and the
Mo2S2 unit of 2 was slightly puckered with dihedral
angle of 12.17° between Mo(1)ꢀMo(2)ꢀS(1) and

132
B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
Table 3
Mo(1)ꢀMo(2)ꢀS(2) due to the introduction of the third
SPh bridge. For the third bridge, the MoꢀS bond
,
Selected bond lengths (A) and bond angles (°) of [Et4N][Mo3(CO)6-
(SPh)3] (2)
,
distance is 2.592(3) A and MoꢀSꢀMo angle is 67.66°.
Around the [Mo2S3] core, there are three carbonyls
coordinated to each MoI atom and one phenyl group
linking to each sulfur atom. Two phenyl groups on the
S atoms of Mo2S2 plane are on the same side of the
M2S2 plane resulting in syn-configuration which is dif-
ferent from the anti-configuration in Mo2(SPh)2(CO)8.
The structure of the anion of 2 could be described as
face-shared bi-octahedron (F).
Bond lengths
Mo(1)ꢀMo(2)
Mo(1)ꢀS(1)
Mo(1)ꢀS(2)
Mo(1)ꢀS(3)
Mo(1)ꢀC(1)
Mo(1)ꢀC(2)
Mo(1)ꢀC(3)
Mo(2)ꢀS(1)
Mo(2)ꢀS(2)
Mo(2)ꢀS(3)
Mo(2)ꢀC(4)
2.877(2)
2.462(3)
2.462(3)
2.576(3)
1.95(1)
1.93(2)
1.97(1)
2.470(4)
2.476(3)
2.592(3)
1.97(1)
Mo(2)ꢀC(5)
Mo(2)ꢀC(6)
S(1)ꢀC(11)
S(2)ꢀC(21)
S(3)ꢀC(31)
O(1)ꢀC(1)
O(2)ꢀC(2)
O(3)ꢀC(3)
O(4)ꢀC(4)
O(5)ꢀC(5)
O(6)ꢀC(6)
1.91(2)
1.97(1)
1.77(2)
1.778(9)
1.76(2)
1.16(1)
1.15(1)
1.17(1)
1.15(1)
1.16(2)
1.16(1)
Bond angles
Mo(2)ꢀMo(1)ꢀS(1)
Mo(2)ꢀMo(1)ꢀS(2)
Mo(2)ꢀMo(1)ꢀS(3)
Mo(2)ꢀMo(1)ꢀC(1) 136.2(4)
Mo(2)ꢀMo(1)ꢀC(2) 106.8(3)
Mo(2)ꢀMo(1)ꢀC(3) 135.3(3)
S(1)ꢀMo(1)ꢀS(2)
S(1)ꢀMo(1)ꢀS(3)
S(1)ꢀMo(1)ꢀC(1)
S(1)ꢀMo(1)ꢀC(2)
S(1)ꢀMo(1)ꢀC(3)
S(2)ꢀMo(1)ꢀS(3)
S(2)ꢀMo(1)ꢀC(1)
S(2)ꢀMo(1)ꢀC(2)
S(2)ꢀMo(1)ꢀC(3)
S(3)ꢀMo(1)ꢀC(1)
S(3)ꢀMo(1)ꢀC(2)
S(3)ꢀMo(1)ꢀC(3)
C(1)ꢀMo(1)ꢀC(2)
C(1)ꢀMo(1)ꢀC3
C(2)ꢀMo(1)ꢀC3
54.45(7) Mo(1)ꢀMo(2)ꢀS(1)
54.49(7) Mo(1)ꢀMo(2)ꢀS(2)
56.44(7) Mo(1)ꢀMo(2)ꢀS(3)
54.17(7)
54.14(6)
55.91(7)
,
It is worth noting that the axial MoꢀC (1.92 A) is
,
shorter than the equatorial MoꢀC (1.97 A) in complex
Mo(1)ꢀMo(2)ꢀC(4) 136.2(4)
Mo(1)ꢀMo(2)ꢀC(5) 108.6(4)
Mo(1)ꢀMo(2)ꢀC(6) 135.7(4)
2, and both the axial and equatorial MoꢀC distances in
2 are shorter than that in Mo2(SPh)2(CO)8 (2.05 and
2.02 A). This means that the carbonyls of 2 are more
difficult to be further substituted. In fact, quartet
bridge-compound or the other product resulted from
further substitution of carbonyls of 2 are not isolated,
at least in this reaction system, so far.
,
108.1(2)
S(1)ꢀMo(2)ꢀS(2)
107.4(1)
77.25(9)
166.8(4)
95.5(4)
85.0(4)
72.9(1)
84.6(4)
96.6(3)
178(1)
177.7(9)
175(2)
179(1)
177.2(9)
177(1)
120.7(9)
77.71(9) S(1)ꢀMo(2)ꢀS(3)
166.8(4)
95.0(4)
84.7(3)
S(1)ꢀMo(2)ꢀC(4)
S(1)ꢀMo(2)ꢀC(5)
S(1)ꢀMo(2)ꢀC(6)
73.42(9) S(2)ꢀMo(2)ꢀS(3)
84.1(4)
94.8(3)
164.4(3)
102.0(4)
163.0(3)
101.8(4)
88.6(5)
82.5(5)
92.6(5)
S(2)ꢀMo(2)ꢀC(4)
S(2)ꢀMo(2)ꢀC(5)
Mo(1)ꢀC(1)ꢀO(1)
Mo(1)ꢀC(2)ꢀO(2)
Mo(1)ꢀC(3)ꢀO(3)
Mo(2)ꢀC(4)ꢀO(4)
Mo(2)ꢀC5ꢀO5
Mo(2)ꢀC6ꢀO6
S(1)ꢀC(11)ꢀC(12)
Table 2
,
Selected bond lengths (A) and bond angles (°) for [W2(SPh)2(CO)8]
(1)
Complex 3 consists of a cation [Bu4N]+ and an anion
[(OC)4Mo(SPh)2Mo(CO)2(S2CNEt2)]−. As shown in
Fig. 3, the structure of the anion of 3 possesses an
unsymmetrical rhombic core [Mo2S2] with two different
Bond lengths
W(1)ꢀW(1%)
W(1)ꢀS(1)
W(1)ꢀS(1%)
W(1)ꢀC(1)
W(1)ꢀC(2)
W(1)ꢀC(3)
2.9691(7)
2.477(2)
2.476(2)
2.02(2)
2.00(1)
2.06(1)
W(1)ꢀC(4)
S(1)ꢀC(11)
O(1)ꢀC(1)
O(2)ꢀC(2)
O(3)ꢀC(3)
O(4)ꢀC(4)
2.03(2)
1.808(9)
1.15(1)
1.14(1)
1.13(1)
1.12(1)
,
MoꢀS distances (average Mo(1)ꢀS of 2.41 A and
,
Mo(2)ꢀS of 2.55 A). Around the core, there are four
carbonyls coordinated to one Mo atom and two car-
bonyls and one dithiocarbamate ligand S2CNEt2 coor-
dinated to another Mo atom forming different
coordination environments of the two Mo atoms. The
whole geometry could be considered as an egde-shared
bi-octahedron (G). Two phenyl-rings link to the sulfur
atoms in anti-configuration relative to the Mo2S2 plane.
In terms of the different values of Mo(1)ꢀS(Ph) and
Mo(2)ꢀS(Ph) bond distances in 3 and consulting the
Bond angles
W(1)ꢀW(1%)ꢀS(1)
W(1%)ꢀW(1)ꢀS(1)
W(1%)ꢀW(1)ꢀC(1)
W(1%)ꢀW(1)ꢀC(2) 137.5(3)
W(1%)ꢀW(1)ꢀC(3) 89.7(3)
W(1%)ꢀW(1)ꢀC(4) 137.5(3)
S(1)ꢀW(1)ꢀS(1%)
S(1)ꢀW(1)ꢀC(1)
S(1)ꢀW(1)ꢀC(2)
S(1)ꢀW(1)ꢀC(3)
S(1)ꢀW(1)ꢀC(4)
S(1%)ꢀW(1)ꢀC(1)
S(1%)ꢀW(1)ꢀC(2)
S(1%)ꢀW(1)ꢀC(3)
S(1%)ꢀW(1)ꢀC(4)
53.15(6)
53.20(5)
94.5(3)
C(1)ꢀW(1)ꢀC(2)
C(1)ꢀW(1)ꢀC(3)
C(1)ꢀW(1)ꢀC(4)
C(2)ꢀW(1)ꢀC(3)
C(2)ꢀW(1)ꢀC(4)
C(3)ꢀW(1)ꢀC(4)
W(1)ꢀS(1)ꢀW(1%)
W(1)ꢀS(1)ꢀC(11)
W(1%)ꢀS(1)ꢀC(11)
W(1)ꢀC(1)ꢀO(1)
W(1)ꢀC(2)ꢀO(2)
W(1)ꢀC(3)ꢀO(3)
W(1)ꢀC(4)ꢀO(4)
S(1)ꢀC(11)ꢀC(12)
S(1)ꢀC(11)ꢀC(16)
84.2(4)
173.9(5)
91.0(4)
95.7(4)
84.9(4)
82.9(4)
73.66(6)
117.6(3)
113.3(4)
175(1)
175(2)
176.8(9)
179(2)
124.5(8)
116.1(9)
106.34(6)
85.7(3)
103.1(3)
82.9(3)
162.1(3)
82.3(3)
163.7(3)
96.7(3)
86.1(3)
,
Mo(I)-complexes [Mo2(SPh)2(CO)8] (MoꢀS, 2.474 A)
and Mo(0)-complex, [Mo2(SPh)2(CO)8]2− (MoꢀS, 2.608
,
A), the two Mo atoms in compound 3 are obviously in
different oxidation states and the oxidation state of the
Mo(2) with four carbonyl ligands is between +1 and 0,
and the valence of the Mo(1) atom with S2CNEt2

B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
133
,
,
,
ligand is higher than +1. This indicates that the un-
symmetric substitution mode resulting from the intro-
of 2.55 A, W(2)ꢀS of 2.43 A and W(1)ꢀW(2) of 2.996 A
(Table 6). The whole structure of 4 is similar to that of
the anion of complex 3 except for the different coordi-
nation positions of DPPM and S2CNEt2. The DPPM
coordinates to two equatorial positions of one W atom
in 4 (Fig. 4) and the S2CNEt2 coordinates to one axial
and one equatorial positions of one Mo atom in 3 (Fig.
3). This is obviously due to the larger steric demand of
DPPM compared to S2CNEt2. DPPM not only can
coordinate to two equatorial positions of one metal
atom but also can bridge two metal atoms in axial
positions if the steric hindrance could be effectively
reduced in the final product. In fact, the Mo compound
with DPPM bridge, [Mo2(m-SPh)2(CO)6(m-DPPM)], in
which the phenyl rings are in syn-arrangement relative
to Mo2S2 unit plane, have been isolated [10]. In examin-
ing the WꢀS bond distances of W(0)-complex,
duction of dithiocarbamate ligand leads to
a
Mo(1) “ Mo(2) charge transfer and formation of a
mixed valence complex. The S2CNEt2 ligand replaces
one axial carbonyl and one equatorial carbonyl on a
Mo atom in 3 rather than bridges two Mo atoms. The
S2CNEt2 ligand in 3 is evidently a conjugate system in
,
terms of the CꢀN of 1.34 A (between single and double
bonds), CNC of ca. 120°, SCN of 122° and SCS of
114°.
[W2(SCH2CO2Me)2(CO)8]2−
(2.58
A)
[16],
,
[W2(SPh)2(CO)8]2− (2.59 A) [17] and W(I)-complex 1
,
,
(2.47 A), it can be found that, similar to complex 3, the
oxidation state of W(2) attached to the DPPM ligand
(\ +1) is higher than the valence of W1 with four
The complex 4, [W2(SPh)2(CO)6(DPPM)], also con-
tains an unsymmetrical rhombic W2S2 unit with W(1)ꢀS
Table 4
,
Selected bond lengths (A) and bond angles (°) of 3
Bond lengths
Mo(1)ꢀC(2)
Mo(1)ꢀC(1)
Mo(1)ꢀS(1)
Mo(1)ꢀS(2)
Mo(1)ꢀS(11)
Mo(1)ꢀS(12)
Mo(1)ꢀMo(2)
Mo(2)ꢀC(3)
Mo(2)ꢀC(5)
Mo(2)ꢀC(4)
1.921(9)
1.990(11)
2.362(2)
2.451(2)
2.488(2)
2.592(4)
3.0396(10)
1.952(13)
1.981(11)
2.016(10)
Mo(2)ꢀC(6)
Mo(2)ꢀS(1)
Mo(2)ꢀS(2)
S(1)ꢀC(11)
S(2)ꢀC(21)
S(11)ꢀC(0)
S(12)ꢀC(0)
N(0)ꢀC(0)
N(0)ꢀC(03)
N(0)ꢀC(01)
2.023(9)
2.552(2)
2.554(2)
1.791(8)
1.794(8)
1.715(8)
1.699(8)
1.340(9)
1.463(10)
1.499(10)
C(01)ꢀC(02)
C(03)ꢀC(04)
C(1)ꢀO(1)
C(2)ꢀO(2)
C(3)ꢀO(3)
C(4)ꢀO(4)
C(5)ꢀO(5)
C(6)ꢀO(6)
1.479(13)
1.492(12)
1.158(10)
1.171(9)
1.154(11)
1.132(10)
1.135(10)
1.149(9)
Bond angles
C(2)ꢀMo(1)ꢀC(1)
C(2)ꢀMo(1)ꢀS(1)
C(1)ꢀMo(1)ꢀS(1)
C(2)ꢀMo(1)ꢀS(2)
C(1)ꢀMo(1)ꢀS(2)
S(1)ꢀMo(1)ꢀS(2)
C(2)ꢀMo(1)ꢀS(11)
C(1)ꢀMo(1)ꢀC(11)
S(1)ꢀMo(1)ꢀS(11)
S(2)ꢀMo(1)ꢀS(11)
C(2)ꢀMo(1)ꢀS(12)
C(1)ꢀMo(1)ꢀS(12)
S(1)ꢀMo(1)ꢀS(12)
S(2)ꢀMo(1)ꢀS(12)
S(11)ꢀMo(1)ꢀS(12)
C(2)ꢀMo(1)ꢀMo(2)
C(1)ꢀMo(1)ꢀMo(2)
S(1)ꢀMo(1)ꢀMo(2)
S(2)ꢀMo(1)ꢀMo(2)
S(11)ꢀMo(1)ꢀMo(2)
S(12)ꢀMo(1)ꢀMo(2)
C(3)ꢀMo(2)ꢀC(5)
C(3)ꢀMo(2)ꢀC(4)
78.5(4)
103.1(2)
89.5(3)
C(5)ꢀMo(2)ꢀC(4)
C(3)ꢀMo(2)ꢀC(6)
C(5)ꢀMo(2)ꢀC(6)
C(4)ꢀMo(2)ꢀC(6)
C(3)ꢀMo(2)ꢀS(1)
C(5)ꢀMo(2)ꢀS(1)
C(4)ꢀMo(2)ꢀS(1)
C(6)ꢀMo(2)ꢀS(1)
C(3)ꢀMo(2)ꢀS(2)
C(5)ꢀMo(2)ꢀS(2)
C(4)ꢀMo(2)ꢀS(2)
C(6)ꢀMo(2)ꢀS(2)
S(1)ꢀMo(2)ꢀS(2)
C(3)ꢀMo(2)ꢀMo(1)
C(5)ꢀMo(2)ꢀMo(1)
C(4)ꢀMo(2)ꢀMo(1)
C(6)ꢀMo(2)ꢀMo(1)
S(1)ꢀMo(2)ꢀMo(1)
S(2)ꢀMo(2)ꢀMo(1)
C(11)ꢀS(1)ꢀMo(1)
C(11)ꢀS(1)ꢀMo(2)
Mo(1)ꢀS(1)ꢀMo(2)
C(21)ꢀS(2)ꢀMo(1)
87.9(4)
89.9(4)
86.0(4)
173.9(4)
172.8(4)
85.6(3)
95.6(3)
84.8(3)
85.6(3)
172.7(3)
86.8(3)
99.2(2)
99.95(7)
136.7(3)
133.8(3)
88.7(3)
96.1(2)
49.02(5)
51.09(5)
119.8(3)
112.9(3)
76.33(6)
114.5(3)
C(21)ꢀS(2)ꢀMo(2)
Mo(1)ꢀS(2)ꢀMo(2)
C(0)ꢀS(11)ꢀMo(1)
C(0)ꢀS(12)ꢀMo(1)
C(0)ꢀN(0)ꢀC(03)
C(0)ꢀN(0)ꢀC(01)
C(03)ꢀN(0)ꢀC(03)
N(0)ꢀC(0)ꢀS(12)
N(0)ꢀC(0)ꢀS(11)
S(12)ꢀC(0)ꢀS(11)
C(02)ꢀC(01)ꢀN(0)
N(0)ꢀC(03)ꢀC(04)
O(1)ꢀC(1)ꢀMo(1)
O(2)ꢀC(2)ꢀMo(1)
O(3)ꢀC(3)ꢀMo(2)
O(4)ꢀC(4)ꢀMo(2)
O(5)ꢀC(5)ꢀMo(2)
O(6)ꢀC(6)ꢀMo(2)
C(16)ꢀC(11)ꢀS(1)
C(12)ꢀC(11)ꢀS(1)
C(22)ꢀC(21)ꢀS(2)
C(26)ꢀC(21)ꢀS(2)
119.1(3)
74.75(6)
90.1(3)
84.4(2)
86.9(3)
157.5(3)
108.64(8)
104.5(3)
81.1(3)
148.33(8)
89.33(8)
172.7(2)
102.4(3)
84.21(7)
92.84(7)
68.64(7)
92.6(3)
104.4(3)
54.65(6)
54.16(6)
138.15(6)
91.23(5)
89.3(4)
121.5(7)
120.4(7)
118.2(7)
124.1(6)
121.7(6)
114.2(5)
110.9(9)
112.7(8)
174.9(9)
176.7(8)
178.2(10)
175.5(11)
175.5(10)
171.3(8)
125.3(7)
115.5(7)
125.3(6)
114.9(6)
89.2(4)

134
B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
Table 5
,
Selected bond lengths (A) and bond angles (°) of [W2(SPh)2(CO)6(DPPM)] (4)
Bond lengths
W(1)ꢀW(2)
W(1)ꢀS(1)
W(1)ꢀS(2)
W(1)ꢀC(1)
W(1)ꢀC(2)
W(1)ꢀC(3)
W(1)ꢀC(4)
W(2)ꢀS(1)
W(2)ꢀS(2)
2.996(2)
2.541(5)
2.556(5)
1.96(2)
1.98(2)
2.00(2)
2.06(3)
2.437(4)
2.431(4)
W(2)ꢀP(1)
W(2)ꢀP(2)
W(2)ꢀC(5)
W(2)ꢀC(6)
S(1)ꢀC(11)
S(2)ꢀC(21)
P(1)ꢀC
2.489(4)
2.488(4)
2.03(2)
1.98(2)
1.76(2)
1.78(2)
1.85(2)
1.83(2)
1.79(2)
P(2)ꢀC
1.86(2)
1.92(2)
1.81(2)
1.16(2)
1.14(2)
1.15(2)
1.11(2)
1.14(2)
1.17(2)
P(2)ꢀC(51)
P(2)ꢀC(61)
O(1)ꢀC(1)
O(2)ꢀC(2)
O(3)ꢀC(3)
O(4)ꢀC(4)
O(5)ꢀC(5)
O(6)ꢀC(6)
P(1)ꢀC(31)
P(1)ꢀC(41)
Bond angles
W(2)ꢀW(1)ꢀS(1)
W(2)ꢀW(1)ꢀS(2)
W(2)ꢀW(1)ꢀC(1)
W(2)ꢀW(1)ꢀC(2)
W(2)ꢀW(1)ꢀC(3)
W(2)ꢀW(1)ꢀC(4)
S(1)ꢀW(1)ꢀS(2)
S(1)ꢀW(1)ꢀC(1)
S(1)ꢀW(1)ꢀC(2)
S(1)ꢀW(1)ꢀC(3)
S(1)ꢀW(1)ꢀC(4)
S(2)ꢀW(1)ꢀC(1)
S(2)ꢀW(1)ꢀC(2)
S(2)ꢀW(1)ꢀC(3)
S(2)ꢀW(1)ꢀC(4)
C(1)ꢀW(1)ꢀC(2)
C(1)ꢀW(1)ꢀC(3)
C(1)ꢀW(1)ꢀC(4)
C(2)ꢀW(1)ꢀC(3)
C(2)ꢀW(1)ꢀC(4)
C(3)ꢀW(1)ꢀC(4)
W(1)ꢀW(2)ꢀS(1)
W(1)ꢀW(2)ꢀS(2)
W(1)ꢀW(2)ꢀP(1)
W(1)ꢀW(2)ꢀP(2)
W(1)ꢀW(2)ꢀC(5)
W(1)ꢀW(2)ꢀC(6)
51.4(2)
52.2(1)
134.3(6)
135.6(5)
93.2(7)
90.4(6)
102.6(1)
173.9(7)
84.2(6)
92.1(6)
87.7(7)
83.1(7)
173.1(5)
93.4(7)
91.3(6)
90.1(8)
89.7(9)
90.1(9)
85.7(8)
89.6(9)
175.2(8)
54.6(2)
56.0(1)
145.9(1)
146.2(2)
93.4(5)
88.8(6)
S(1)ꢀW(2)ꢀS(2)
S(1)ꢀW(2)ꢀP(1)
S(1)ꢀW(2)ꢀP(2)
S(1)ꢀW(2)ꢀC(5)
S(1)ꢀW(2)ꢀC(6)
S(2)ꢀW(2)ꢀP(1)
S(2)ꢀW(2)ꢀP(2)
S(2)ꢀW(2)ꢀC(5)
S(2)ꢀW(2)ꢀC(6)
P(1)ꢀW(2)ꢀP(2)
P(1)ꢀW(2)ꢀC(5)
P(1)ꢀW(2)ꢀC(6)
P(2)ꢀW(2)ꢀC(5)
P(2)ꢀW(2)ꢀC(6)
C(5)ꢀW(2)ꢀC(6)
W(1)ꢀS(1)ꢀW(2)
W(1)ꢀS(1)ꢀC(11)
W(2)ꢀS(1)ꢀC(11)
W(1)ꢀS(2)ꢀW(2)
W(1)ꢀS(2)ꢀC(21)
W(2)ꢀS(2)ꢀC(21)
W(2)ꢀP(1)ꢀC
109.6(2)
159.5(5)
91.7(2)
85.4(5)
97.3(6)
90.9(1)
158.7(2)
97.0(5)
82.9(5)
67.8(1)
91.2(5)
86.0(5)
85.3(5)
93.9(5)
177.2(8)
74.0(1)
107.7(7)
119.6(6)
73.8(1)
1105.4(5)
118.9(7)
97.4(6)
123.6(6)
119.1(6)
102.6(8)
108(1)
W(2)ꢀP(2)ꢀC
97.3(7)
W(2)ꢀP(2)ꢀC(51)
W(2)ꢀP(2)ꢀC(61)
CꢀP(2)ꢀC(51)
CꢀP(2)ꢀC(61)
C(51)ꢀP(2)ꢀC(61)
P(1)ꢀCꢀP(2)
122.0(5)
117.7(7)
104.7(9)
108.2(9)
105.1(7)
97.1(9)
171(3)
177(2)
176(3)
173(2)
174(1)
176(2)
116(1)
125(1)
122(1)
118(1)
120(1)
119(1)
121(1)
1120(1)
121(1)
119(1)
120(1)
120(1)
W(1)ꢀC(1)ꢀO(1)
W(1)ꢀC(2)ꢀO(2)
W(1)ꢀC(3)ꢀO(3)
W(1)ꢀC(4)ꢀO(4)
W(2)ꢀC(5)ꢀO(5)
W(2)ꢀC(6)ꢀO(6)
S(1)ꢀC(11)ꢀC(12)
S(1)ꢀC(11)ꢀC(16)
S(2)ꢀC(21)ꢀC(22)
S(2)ꢀC(21)ꢀC(26)
P(1)ꢀC(31)ꢀC(32)
P(1)ꢀC(31)ꢀC(36)
P(1)ꢀC(41)ꢀC(42)
P(1)ꢀC(41)ꢀC(46)
P(2)ꢀC(51)ꢀC(52)
P(2)ꢀC(51)ꢀC(56)
P(2)ꢀC(61)ꢀC(62)
P(2)ꢀC(61)ꢀC(62)
W(2)ꢀP(2)ꢀC(31)
W(2)ꢀP(1)ꢀC(41)
CꢀP(1)ꢀC(31)
CꢀP(1)ꢀC(41)
C(31)ꢀP(1)ꢀC(41)
103.6(8)
carbonyls (\0 and B +1) in complex 4. Apparently,
there is a W(1) “ W(2) charge transfer in 4 because of
the introduction of the DPPM ligand. In contrast to
bridge-forming substitution mode C, the unsymmetrical
substitution mode D leads to slight expansion of the
,
,
M2S2 core by ca. 0.05 A of MꢀM, ca. 0.02 A of MꢀS
bond distances and ca. 0.35° of MSM angle.
It is worth pointing out that the carbonyls of
Mo(CO)4-unit in 3 and W(CO)4 in 4 seem to be further
substituted by ligands because the Mo(CO)4-unit in 3
and the W(CO)4-unit in 4 are very similar to that in
parent compounds, [Mo2(SPh)2(CO)8] and [W2(SPh)2-
(CO)8] (1), respectively, but neither [Mo2(SPh)2-
(CO)4(S2CNEt2)2]2− and [W2(SPh)2(CO)4(DPPM)2] nor
other metal carbonyl-thiolates with multi-S2CNEt2 or
DPPM ligands have been isolated even if an excess
Fig. 1. The structure of [W2(SPh)2(CO)8] (1).

B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
135
3.3. IR, NMR and cyclic 6oltammetry
The selected IR data of complexes 1–5 are listed in
Table 7. It is easy to find that the wMCꢀO in substituted
complexes 2, 3, 4 and 5 are lower than that in parent
complexes 1 and [Mo2(SPh)2(CO)8], and wMꢀS of the
ligand substituted complexes are higher than that of
parent complexes. The lower wMCꢀO of 1799 and 1840
cm−1 in complexes 3 and 4, respectively are found in
the
M(0)-compounds
[Mo2(SPh)2(CO)8]2−
and
[W2(SPh)2(CO)8]2− (1770–1790) [1,3,17,18] indicating
the existence of a metal-carbonyl unit similar to
M0(CO)4-unit. In fact, the X-ray crystal structure
showed that the Mo(CO)4- and W(CO)4-units in 3
and 4, respectively, are similar to that in [Mo2(SPh)2-
(CO)8]2− [3] and [W2(SPh)2(CO)8]2− [17].
Fig. 2. The structure of the anion 0f [Et4N][Mo2(SPh)3(CO)6] (2).
The 1H- and 13C-NMR of the ligand substituted
complexes have been measured and focused on the
1
benzene rings (Table 8). The H- and 13C-NMR of the
PhS ligands in ligand-substituted complexes are ob-
served at 7.14–7.76 and 125.7–148.3 ppm, respectively,
which are similar to that in the parent complex 1 and
[Mo2(SPh)2(CO)8]. Complex 2 contains two sets of
l(1H) and l(13C) indicating two kinds of Ph-groups in
different environment. This is consistent with the result
from the X-ray crystal structural data of 2.
Inspecting the 95Mo-NMR, it can be found that there
are two l(95Mo) for complex 3. This implies that
complex 3 exists with two kinds of Mo atoms in
different coordination environment and oxidation
states.
The cyclic voltammograms of 1, 2, 3 and 4 are
showed in Fig. 5 and the selected CV data are listed in
Table 9. As is reported before, complex 1 and
[Mo2(SPh)2(CO)8] underwent reversible two-electron re-
duction at −0.35 V vs SCE (−0.4/−0.3 V vs SCE)
[1,12] and the current parameter (IPa/wi/2AC) of com-
plex 1 and [Mo2(SPh)2(CO)8] are 1475 and 1240 A cm
s1/2 w−i/2 mol−1, respectively, (Fig. 5a and b, Table 9).
Their electrochemical reaction could be described as
following Eq. (a):
Fig. 3. The structure of the anion of [Bu4N][Mo2(SPh)2(CO)6-
(S2CNEt2)] (3).
ligands were used in the reaction. This is obviously due
to the decreasing stability of the product with multi-lig-
and and less of carbonyls.
According to the elemental analysis data of 5 and the
similarity of the IR spectra of 5 and a trans-substitu-
−
2e
[M2(SPh)2(CO)8]0
X
[M2(SPh)2(CO)8]2−
−0.40 V
(M=M, W)
(a)
As is shown in Fig. 5c, the complex 2 underwent a
reversible reduction at −0.818(−0.865/−0.770) V vs
SCE, with IPc/IPa:1. Its current parameter (IPa/w1/
2AC) of 1121 A cm s1/2 w−1/2 mol−1 is about twice as
much as that of ferrocene (688 A cm s1/2 w−1/2
mol−1obtained in identical conditions). Ferrocene is
known to undergo one-electron redox, thus, complex 2
should undergo reversible two-electron reduction at
−0.818 V as described in following Eq. (b):
tion mode A product, [M2(SPh)2(CO)6(PPh3)2] (wCO
,
2010(m), 1980(s), 1940(s) and 1905(s) cm−1) [4] in
which the P atoms of PPh3 ligands coordinate to two M
atoms, the compound 5 could be assumed as a polymer
[(OC)3W(SPh)2W(CO)3DPPM]m in which the two phos-
phor atoms of DPPM coordinated to two W atoms in
two different [(OC)3W(SPh)2W(CO)3] units forming an
infinite chain product although the structure of 5 has
not been determined because of its lesser solubility and
difficulty to obtain good quality of crystal.
−
2e
[Mo2(SPh)3(CO)6]−
X
[Mo2(SPh)3(CO)6]3− (b)
−0.865 V

136
B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
[W2(SPh)2(CO)6DPPM]0
The electrochemical behavior of complex 2 is consistent
with that of [Mo2(SPh)2(CO)6(MeCN)2] (0.8 V vs.
SCE), which is a substitution mode A product.
−
e
X
{W2(SPh)2(CO)6DPPM}−
−0.383 V
−
e
The cyclic voltammogram of complex 4, as shown in
Fig. 5d, contained two redox couples at −0.383 and
−0.747 V vs SCE with IPc/IPa:1 and their current
X
[W2(SPh)2(CO)6DPPM]2−
(c)
−0.747 V
According to the fact that the complex 4 contains two
W atoms in different coordination environment: a
lower valence tungsten atom (WL) in W(CO)4-unit and
parameters are 551 and 531 A cm s1/2 w−1/2 mol−1
.
This means that complex 4 undergoes quasi-reversible
one-electron redox at −0.383 and −0.747 V vs SCE.
This behavior could be expressed as following Eq. (c):
a
higher valence tungsten atom (WH) in
W(CO)2(DPPM)-unit (0BLB +1 and +1BHB +
Fig. 4. The structure of [W2(SPh)2(CO)6DPPM] (4).
Table 6
Structural parameters of M2S2 units in 1, 2, 3 and 4, and arrangement of the Ph rings relative to the M2S2ꢀunit plane
Complexes
1
2
3
4
[Mo2(SPh)2(CO)8]
,
MꢀS (A)
MꢀM (A)
2.47
2.969
73.7
2.46
2.877
71.38
2.55, 2.41
3.039
74.25
2.55, 2.43
2.996
74.0
2.47
2.962
73.56
,
MSM (°)
Arrangement of the Ph rings
anti-
syn-
anti-
anti-
anti-
,
MꢀC (axial) (A)
MꢀC (equatorial) (A)
CꢀO (A)
2.06, 2.03
2.02, 2.00
1.135
1.93, 1.91
1.96, 1.97
1.160
1.92, 2.02
1.99, 1.96
1.150
2.03, 2.01
1.98, 1.97
1.145
2.05, 2.05
2.00, 2.04
1.138
,
,

B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
137
Table 7
Complex 2 still keeps the two-electron transfer charac-
ter because of its remaining the planarity and symmetry
of the Mo2S2-unit. Complex 4 no longer possesses
two-electron transfer character for its planar W2S2-unit
lost symmetry. Complex 3 exhibited somewhat more
complicated CV behavior implying some decomposition
of the sample. However, obviously, complex 3 does not
possess two-electron transfer character because of the
same reason as complex 4.
Selected IR data of 1, 2, 3, 4, 5 and parent [Mo2(SPh)2(CO)8]
Complexes
wMCꢀO
lMꢀCꢀO
wMꢀC
wMꢀS
1
2031s
1963s
1939s
569m
557m
488m
459m
357m
339m
426m
407m
2
1998m
1965s
1940s
1917s
1849s
608m
579m
507m
498m
370w
351m
433sh
419m
4. Summary
3
2017s
1928s
1898s
1799s
507m
500m
476m
372m
361m
345w
447m
436m
Four new dinuclear M(I) complexes (M=Mo or W),
[W2(SPh)2(CO)8] (1), [Mo2 (SPh)3(CO)6]− (2), [Mo2-
(SPh)2(CO)6(S2CNEt2)]− (3) and [W2(SPh)2(CO)6-
(DPPM)] (4) and a polymer [W2(SPh)2(CO)6(DPPM)]m
(5) were synthesized by the reaction of [M2(SPh)2(CO)8]
(M=Mo, W) with appropriate ligands and reaction
conditions. The complexes were studied by crystal
structure determination, IR, NMR and CV measure-
ment. Three ligand substitution modes (trans-substitu-
tion mode A, bridge-forming substitution mode C and
unsymmetrical substitution mode D) and two kinds of
planar M2S2-units (symmetrical and unsymmetrical)
were found in the complexes. Modes A and C make the
complexes possess two-electron transfer character and
mode D leads to formation of mixed valence metal
atoms and lose of two-electron transfer character.
4
2033m
1956s
1925s
1840m
598m
575m
559m
357m
339w
318w
428m
409m
374m
5
2006w
1979s 581mm
1927s
1896s
598m
–
426m
413m
548m
[Mo2(SPh)2(CO)8]
2065sh
2030s
1994s
1975s
567/560s
551s
488m
353m
338m
421w
407m
382m
1947s 459wm
2), it is reasonable to speculate that the different redox
event occurs on the different W metal centers. When
the scan goes to negative potential the one-electron
reduction, at first, occurs on the higher valence WH
center, at −0.383 V, and then occurs on the lower
valence WL center at −0.747 V.
Inspecting the changes of CV behavior for ligand
substituted complexes with different substitution modes
it is clear to be found that the two-electron transfer
character of the complexes [M2(SPh)2(CO)8]2−,0 (M=
Mo, W) is not only dependent upon the planarity but
also the symmetry of the M2S2-unit in the complexes.
5. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 165472, 165471, 165583 and
165470 for compounds 1, 2, 3 and 4, respectively.
Copies of this information may be obtained free of
charge from The Director, CCDC, 12, Union
Road, Cambridge CB2 1EZ (Fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
Table 8
Selected 1H-, 13C- and 95Mo-NMR data of 1, 2, 3 and [Mo2(SPh)2(CO)8] (ppm)
Complexes
l
1H (Ph)
l
13C (Ph)
l
95Mo
oꢀH
mꢀH
pꢀH
oꢀC
mꢀC
pꢀC
2
7.46
7.55
7.20
7.38
7.18
7.30
135.5
130.0
128.8
128.0
125.9
124.7
−853.7
3
7.14–7.76
148.3–125.7
−1487.9
–
1
7.26–7.55
7.25–7.51
142.5–128.0
142.5–128.0
[Mo2(SPh)2(CO)8]
−1110.3

138
B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
Fig. 5. The voltammograms of 1, 2, 3, 4 and [Mo2(SPh)2(CO)6]. (a) 1 in Me2CO, w, 100 mv s−1, sample concentration, 0.001 M; (b)
[Mo2(SPh)2(CO)6] in Me2CO, w, 100 mv s−1, sample concentration, 0.001 M; (c) 2 in Me2CO, w, 100 mv s−1, sample concentration, 0.001 M; (d)
4 in Me2CO, w, 100 mv s−1, sample concentration, 0.001 M; (e) 3 in Me2CO, w, 100 mv s−1, sample concentration, 0.001 M.
Table 9
CV data of 1, 2, 3, 4 and [Mo2(SPh)2(CO)8] (V vs. SCE)
Complexes
EC
Ea
E1/2
iPc/iPa
I
Pa/w1/2AC
1
2
4
−0.40
−0.30
−0.35
0.962
0.983
1475
1121
−0.865
−0.770
−0.818
−0.425
−0.775
−0.340
−0.718
−0.383
−0.747
0.892
0.926
551
531
3
−1.25
−1.17
−0.53
+0.20
−1.21
−0.53
+0.16
+0.63
+0.12
+0.63
[Mo2(SPh)2(CO)8]
−0.40
−0.30
−0.35
0.900
1240

B. Zhuang et al. / Journal of Organometallic Chemistry 640 (2001) 127–139
139
[7] G. Pan, B. Zhuang, L. He, J. Chen, J. Lu, Chem. Lett. (1998)
1103.
Acknowledgements
[8] G. Pan, B. Zhuang, J.-T. Chen, Acta Cryst. C54 (1998) 1815.
[9] G. Pan, B. Zhuang, J.-T. Chen, Acta Cryst. C55 (1999) 297.
[10] G. Pan, B. Zhuang, L. He, J.-T. Chen, J. Chen, J. Lu, J.
Organomet. Chem. 580 (1999) 313.
[11] B. Zhuang, L. Huang, L. He, Chin. J. Struct. Chem. 14 (1995)
359.
We thank NNSFC (the National Natural Science
foundation of China) and SKLSC (State Key Labora-
tory of Structural Chemistry) for financial support.
[12] B. Zhuang, J.W. McDonald, F.A. Schultz, W.E. Newton, Inorg.
Chim. Acta 99 (1985) L29.
References
[13] R.C.G. Killean, J.L. Lawrence, Acta Cryst. 25 (1969) 1750 Sect.
B.
[14] MoLEN, An Interactive Structure Solution Procedure, Enraf-
Nonius, Delft, The Netherlands, 1990.
[15] G.M. Shedrick, SHELXTL Version 5.03, Siemens Analytical X-ray
Instrument Inc., Madison, WI, 1990.
[16] H. Sun, B. Zhuang, L. Huang, L. He, Chin. J. Struct. Chem. 18
(1999) 32.
[1] B. Zhuang, J.W. McDonald, F.A. Schultz, W.E. Newton,
Organometallics 3 (1984) 943.
[2] D.A. Smith, B. Zhuang, W.E. Newton, J.W. McDonald, F.A.
Schultz, Inorg. Chem. 26 (1987) 2524.
[3] B. Zhuang, L. Huang, L. He, Y. Yang, J. Lu, Inorg. Chim. Acta
157 (1989) 85.
[4] (a) B. Zhuang, L. Huang, L. He, Y. Yang, J. Lu, Acta Chim.
Sinica 47 (1989) 25;
[17] D.J. Darensbourg, K.M. Sanchez, J. Reibenspies, Inorg. Chem.
27 (1988) 3636.
(b) Inorg. Chim. Acta 127 (1987) L7.
[5] G. Pan, B. Zhuang, J.-T. Chen, Acta Cryst. C54 (1998) 1580.
[6] G. Pan, B. Zhuang, J.-T. Chen, Acta Cryst. C55 (1999) 298.
[18] L. He, B. Zhuang, B. Chen, S. Cai, L. Zhang, Chin. J. Struct.
Chem. 16 (1997) 129.