Cobalt(III)-mediated disulfuration and hydrosulfuration of alkynes

Article abstract of DOI:10.1021/ic801199e

Disulfuration and hydrosulfuration of alkynes mediated by an unusual square-planar tetrathiolate cobalt(III) complex [Cp₂Co] ⁺[Co(S₂C₂B₁₀H₁₀) ₂]^-, 1, lead to a series of cobalt-free carboranyl vinyl sulfides 2-9. All new complexes 1, 2, 3, 4, 5, 6, 7, 8, and 9 were characterized by NMR spectroscopy (¹H, ¹¹B, ¹³C), and X-ray structural analyses were performed for 1, 2, 3, 5, 6, 7, and 9.

Full text of DOI:10.1021/ic801199e

Inorg. Chem. 2008, 47, 7928-7933
Cobalt(III)-Mediated Disulfuration and Hydrosulfuration of Alkynes
Bao-Hua Xu, Xu-Qing Peng, Zhi-Wei Xu, Yi-Zhi Li, and Hong Yan*
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering,
The Joint Laboratory of Metal Chemistry, Nanjing UniVersity-Jin Chuan Group Ltd., Nanjing
UniVersity, Nanjing, JiangSu 210093, China
Received May 8, 2008
Disulfuration and hydrosulfuration of alkynes mediated by an unusual square-planar tetrathiolate cobalt(III) complex
[Cp2Co]+[Co(S2C2B10H10)2]-, 1, lead to a series of cobalt-free carboranyl vinyl sulfides 2-9. All new complexes 1,
2, 3, 4, 5, 6, 7, 8, and 9 were characterized by NMR spectroscopy (1H, 11B, 13C), and X-ray structural analyses
were performed for 1, 2, 3, 5, 6, 7, and 9.
Introduction
A class of electronically unsaturated (16e) complexes
Cp*M(E2C2B10H10) (M ) Co, Rh, Ir; E ) S, Se) containing
a chelating 1,2-dicarba-closo-dodecaborane-1,2-dichalco-
genolate ligand were reported to mediate selective B-H
functionalization of the intramolecular o-carborane cage in
the presence of alkynes that led to novel B-substitution.12,13
The process involved metal-induced B-H activation and
M-B formation. In the present paper we report a novel
square-planar tetrathiolate cobalt(III) ionic complex
[Cp2Co]+[Co(S2C2B10H10)2]-, 1 (Scheme 1) and its reactivity
toward alkynes to generate a series of cobalt-free carboranyl
vinyl sulfides.
The reaction of Li2S2C2B10H10 with CpCo(CO)I2 caused
replacement of the Cp ligand by a [S2C2B10H10]2- moiety.
This led to a square-planar cobalt(III) complex 1 with two
bidentate o-carborane dithiolate ligands as shown in Scheme
1 and Figure 1. The displaced Cp combined with a CpCo
moiety to give the observed countercation Cp2Co+. Presum-
ably the formation of this stable cation is the driving force
for the generation of the unusual square-planar anion
[Co(S2C2B10H10)2]- that was also detected by ESI-MS at m/z
470.95. Note that only very few square-planar cobalt(III)
Alkyl vinyl sulfides and their oxidized derivatives are used
in a wide range of synthetic transformations, for instance,
in cross-coupling,1 Heck reactions,2 sigmatropic rearrange-
ments,3 Diels-Alder reactions,4 and Pauson-Khand reac-
tions5 and as ligands for a number of transformations,6
including C-H activation7 and allylic alkylation.8 On the
other hand, icosahedral carboranes are considered to be
versatile building blocks because of their promising applica-
tions in materials9 and pharmaceuticals.10,11 These provide
significant impetus to search for an efficient synthetic strategy
for the introduction of a carborane entity into a vinyl sulfide
backbone.
* To whom correspondence should be addressed. E-mail: hyan1965@
nju.edu.cn. Fax: (+86)-25-83314502.
(1) (a) Dubbaka, S. R.; Vogel, P. Angew. Chem. 2005, 117, 7848; Angew.
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7928 Inorganic Chemistry, Vol. 47, No. 17, 2008
10.1021/ic801199e CCC: $40.75  2008 American Chemical Society
Published on Web 08/05/2008

Disulfuration and Hydrosulfuration of Alkynes
Scheme 1. Formation of 1 and Its Reactions with Terminal Alkynes
Figure 1. Molecular structure of 1. Selected bond lengths [Å] and angles
[deg]: C(1)-C(2) 1.614(5), Co(1)-S(1) 2.1728(15), Co(1)-S(2) 2.1806(15),
C(2)-S(1) 1.794(4), C(1)-S(2A) 1.798(4); S(1)Co(1)S(2) 84.74(4),
S(1)Co(1)S(2A) 95.26(4).
complexes with tetrathiolate ligands are known14 since the
majority of cobalt(III) complexes are observed with an
octahedral ligand configuration at the metal center.
[Co(S2C2B10H10)2]2- with a cobalt(II) center possesses tet-
rahedral geometry.15
Figure 2. Molecular structure of 2. Selected bond lengths [Å] and angles
[deg]: C(1)-C(2) 1.683(4), S(1)-C(4) 1.743(3), S(2)-C(3) 1.806(3),
S(1)-C(1) 1.814(3), S(2)-C(2) 1.720(3), C(3)-C(4) 1.310(4), C(4)-C(5)
1.492(4); S(1)C(1)C(2)S(2)/S(1)C(4)C(3)S(2) 128.4.
Discussion
It is well-known that cobalt(III) complexes of square-
planar geometry with acacen or salen ligands have been
successfully employed as chiral Lewis acid catalysts in the
enantioselective hetero-Diels-Alder reaction,16 the carbo-
nylene reaction,17 1,3-dipolar cycloaddition of nitrones,18 and
ring opening of epoxides.19 Thus, the square-planar complex
1 with an electron-deficient cobalt center (14e), reactive
Co-S bonds, and the vacant axial positions may offer
similarly diverse reaction chemistries. The terminal alkyne
ethynylferrocene was used to test its reactivity. Unexpectedly,
the ferrocene-substituted dithio-o-carboranes 2 and 3 were
generated (Scheme 1). In 2, one alkyne molecule is added
to the o-carborane dithiolate ligand at two sulfur sites. This
leads to a cobalt-free species containing a bent six-membered
ring with a dihedral angle (128.4°) at the S(1) · · · S(2) vector
Figure 3. Molecular structure of 3. Selected bond lengths [Å] and angles
[deg]: C(1)-C(2) 1.820(6), S(1)-C(1) 1.731(4), S(1)-C(3) 1.781(4),
C(3)-C(4) 1.351(7), S(2)-C(2) 1.740(4), S(2)-C(5) 1.782(5), C(5)-C(6)
1.352(6); C(1)S(1)C(3) 103.5(2), S(1)C(3)C(4) 116.2(4), S(1)C(3)C(7)
117.3(3), C(2)S(2)C(5) 104.9(2), S(2)C(5)C(6) 116.4(3), S(2)C(5)C(17)
115.7(4).
structural type with silicon, instead of sulfur, from the
reaction of a 1,2-bis(dimethylsilyl)carborane nickel species
with alkynes has been described.20
The solid-state structure of 3 indicates that the o-carborane
dithiolate ligand is combined with two vinylferrocenes
(Figure 3). Interestingly, two extra hydrogen atoms are
observed in 3 compared to the starting compounds.
S(1)-C(1)-C(2)-S(2) is nearly planar, and the two thio-
vinyl units are in a transoid arrangement. The orientations
of the vinylferrocenes are different in the dihedral angles
between the Cp ring of the individual ferrocene moieties and
the plane S(1)C(1)C(2)S(2), 120.6° for Fe(1)- and 57.7° for
Fe(2)-vinylferrocene, respectively. In 3, the C(1)-C(2)
distance (1.820 Å) is exceptionally long, as compared with
1
(Figure 2.) The H NMR spectrum shows a singlet at 6.53
ppm assigned to the dCH unit, and its 13C signal is identified
at 112.36 ppm. The carbon atom connected to the ferrocene
unit (Fc-CdCH) is assigned at 141.92 ppm. A similar
(14) (a) Rao, C. P.; Dorfman, J. R.; Holm, R. H. Inorg. Chem. 1986, 25,
428. (b) Kang, B. S.; Peng, J. H.; Hong, M. C.; Wu, D. X.; Chen,
X. T.; Weng, L. H.; Lei, X. J.; Liu, H. Q. Dalton Trans. 1991, 2897.
(c) Millar, M.; Koch, S. A. Inorg. Chem. 1985, 24, 3311.
(15) Smith, H. D.; Robinson, M. A.; Papetti, S. Inorg. Chem. 1967, 6, 1014.
(16) Huang, Y.; Iwama, T.; Rawal, V. H. J. Am. Chem. Soc. 2002, 124,
5950.
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2003, 76, 49.
(18) Mita, T.; Ohtsuki, N.; Ikeno, T.; Yamada, T. Org. Lett. 2002, 4, 2457.
(19) Tokunaga, M.; Larrow, J. F.; Kakiuchi, F.; Jacobsen, E. N. Science
1997, 277, 936.
(20) (a) Lee, J.; Lee, T.; Lee, S. S.; Park, K. M.; Kang, S. O.; Ko, J.
Organometallics 2002, 21, 3922. (b) Kang, Y.; Lee, J.; Kong, Y. K.;
Kang, S. O.; Ko, J. Organometallics 2000, 19, 1722.
Inorganic Chemistry, Vol. 47, No. 17, 2008 7929

Xu et al.
Figure 6. Molecular structure of 7. Selected bond lengths [Å] and angles
[deg]: C(1)-C(2) 1.777(3), S(1)-C(1) 1.766(2), S(1)-C(3) 1.737(2),
C(3)-C(4) 1.307(3); C(1)S(1)C(3) 104.28(10).
Figure 4. Molecular structure of 5. Selected bond lengths [Å] and angles
[deg]: C(1)-C(2) 1.790(4), S(1)-C(1) 1.774(3), S(1)-C(3) 1.740(3),
C(3)-C(4) 1.316(4); C(1)S(1)C(3) 101.90(16).
in this reaction. These suggest that a product type is
determined by the nature of an alkyne. Moreover, the
generation of 3 and 5-7 reflects the regio- and stereoselective
addition of terminal alkynes and is mechanistic in origin.
Very recently, a dithio derivative 1,12-[HS(CH2)3]2-1,12-
C2B10H10 has been reported from a dibromo derivative of
p-carborane.22 However, the hydrosulfuration products of the
types described in this paper are unknown.
The terminal hydrogen atom in the alkynes used above
may be responsible for the two “extra” hydrogen atoms in
the generation of hydrosulfuration species 3, 5-7. To test
this hypothesis, the internal alkyne, dimethyl acetylenedi-
carboxylate, was chosen to react with 1 that led to only
disulfuration products 8 and 9 (Scheme 2.)
Figure 5. Molecular structure of 6. Selected bond lengths [Å] and angles
[deg]: C(1)-C(2) 1.793(3), S(1)-C(1) 1.771(2), S(1)-C(3) 1.731(2),
C(3)-C(4) 1.323(3), C(4)-C(5) 1.451(3), C(8)-C(9) 1.455(3), C(7)-C(8)
1.311(3), S(2)-C(7) 1.740(2), C(2)-S(2) 1.762(2); C(1)S(1)C(3) 101.96(11),
C(2)S(2)C(7) 102.48(11).
8 was identified on the basis of spectroscopic data and
microanalysis. The NMR data demonstrate a symmetric
structure, and the mass spectrum displays a strong peak at
348.1 corresponding to the molecular ion. In 9 the alkyne is
a 2-fold addition to the o-carborane dithiolate ligand at the
two sulfur sites that results in an eight-membered ring as
the typical range found in o-carborane derivatives of
1.62-1.70 Å.21 This reflects a considerable distortion of the
carborane cage that may be attributed to the steric factor of
1
the two vinylferrocene units. The H NMR spectrum of 3
1
indicated in Figure 7. The H and 13C data show two types
contains two singlets at δ 5.78 and 6.13 owing to the geminal
1H nuclei of the respective vinyl protons. The 13C signals at
124.99 (dCH2) and 139.31 ppm (dC-Fc) are also indicative
of the presence of the terminal alkene. The EI-MS analysis
shows the molecular ion peak. These are consistent with the
solid-state structure.
of signals from the alkyne and only one 13C signal from the
carborane. The EI-MS spectrum gives a molecular ion peak
at 490.0. Thus, the spectroscopic data support the solid-state
structure. A 2-fold alkyne insertion into an M-E bond
occurred in the16e complexes Cp*M(E2C2B10H10) (M ) Co,
Rh; E ) S, Se), and the resulting complexes acted as
intermediates in the generation of benzene derivatives from
alkynes.12,13 We therefore envision that 1 may have a
potential for catalytic cyclotrimerization of alkynes. Indeed,
hexamethyl benzene-hexacarboxylate was isolated in a yield
of 10% (based on dimethyl acetylenedicarboxylate used).
Mechanistic Implications. As 3 and 5-7 are unique, their
origins are of interest. The mechanistic implications are
summarized in Scheme 3. The alkyne insertion into one of
the Co-S bonds in 1 may lead to II, in analogy to reported
examples of alkyne insertion into M-S bonds.12 III is
reasonable provided the generated SfCo coordinative bond
is weak enough. The next step is the release of 2 or 4 via
reductive elimination. Both a new alkyne addition to a Co-S
bond and the oxidative addition of a second terminal alkyne
In the case of phenyl acetylene, the structural type 3 was
not generated, and only one product 4, an analogue of 2,
was observed (Scheme 1) based on the spectroscopic data
and microanalysis. In the case of the activated alkyne, methyl
carboxylate acetylene, three hydrosulfuration products 5-7
with the two CdC bonds in Z/Z, Z/E, E/E configurations,
respectively, were isolated in a ratio of appropriate 1:1:1, as
shown in Scheme 1 and Figure 4-6. Again, extra hydrogen
1
atoms were observed in 5-7. The H NMR spectra of the
three structural isomers are similar, showing the vinyl
doublets in a range from 6.02 to 7.51 ppm and different
coupling constants of 16 Hz for E configuration versus 10
Hz for Z configuration. The 13C signals of the carbon atoms
linked to sulfur are shifted to low field approximately 20
ppmrelativetotheoneslinkedtoC(O)intheS-CHdCH-C(O)
unit. Note that the structural type 2 or 4 was not generated
(22) Bregadze, V. I.; Glazun, S. A. Russ. Chem. Bull., Int. Ed. 2007, 56,
(21) Bregadze, V. I. Chem. ReV. 1992, 92, 209.
7930 Inorganic Chemistry, Vol. 47, No. 17, 2008
643.

Disulfuration and Hydrosulfuration of Alkynes
Scheme 2. Reaction of 1 with Dimethyl Acetylenedicarboxylate
to the metal center may give rise to the metal hydride species
V. Hydrogen transfer from the metal to the adjacent olefinic
carbon atom in V then generates the vinyl compound VI,
and repetition from IV to VI may lead to the final products
3, 5, 6, and 7.
On the basis of this mechanism, production of 3 requires
excess alkyne. Indeed, experimentally, we observe that 3 can
not be generated for stoichiometric alkyne addition. The
competitive formation of 3 in CH2Cl2 is less favored than
that of 2, as demonstrated by yields of 10% for 3 versus
70% for 2. The yield of 3 was increased by addition of polar
solvents, for example, an increase in the yield of 3 by 50%
in THF/CH2Cl2 (1:1). This can be attributed to a solvent-
stabilized agostic intermediate, a prerequisite of C-H
oxidative addition that involves an elongation of an agostic
C-H bond.23 Thus, the solvent effect suggests the presence
of a metal hydride. In comparison, HCt CCO2Me leads only
to oxidative addition products 5-7 whereas HCt CPh gives
only reductive elimination product 4. This further demon-
strates that the type of alkyne plays a crucial role in
generating and stabilizing the intermediate metal hydride
species that ultimately determines the variety and yield of
the products. Thus, the consumption of excess terminal
alkynes provides the extra hydrogen atoms for hydrosulfu-
ration. To further confirm this, we used 1-deuterio-2-
ferrocenylethyne to react with 1, and as a consequence, 3
was obtained with a deuterium content of approximate 83%;
this value exactly parallels to the deuterium contents for 2
and the deuterated alkyne. Therefore, the result substantiates
our proposal for the origin of the additional hydrogen atoms
in the hydrosulfuration products (see the Supporting Infor-
mation for the detailed NMR data).
Figure 7. Molecular structure of 9. Selected bond lengths [Å] and angles
[deg]: C(1)-C(1A) 1.717(3), S(1)-C(1) 1.786(3), S(1)-C(2) 1.769(3),
C(2)-C(3)1.360(4);C(1)C(1A)S(1A)S(1)/S(1)C(2)C(3)C(3A)76.3,C(1)C(1A)S(1A)S(1)/
C(3)C(3A)C(2A)S(1A) 76.3, S(1)C(2)C(3)C(3A)/C(3)C(3A)C(2A)S(1A)
77.6.
In summary, an unusual square-planar tetrathiolate cobal-
t(III) complex [Cp2Co]+[Co(S2C2B10H10)2]- (1) was synthe-
sized and used for the disulfuration and hydrosulfuration of
alkynes. An effective synthetic route that incorporates an
alkyne into an o-carborane dithiolate unit for carboranyl vinyl
sulfides in a one-pot reaction has proved successful. The
resulting novel products may be served as valuable synthetic
intermediates or precursors to materials and bioactive
molecules.
Scheme 3. Proposed Mechanism for the Reaction of 1 with Terminal
Alkynes
Experimental Section
General Information. n-Butyllithium (2.0 M in hexanes, Ald-
rich), o-carborane (Katchem, Czech), methyl acetylene monocar-
boxylate (Alfa Aesar), phenylacetylene (Alfa Aesar), and dimeth-
ylacetylenedicarboxylate (Aldrich) were used as supplied.
Ethynylferrocene,24 1-deuterio-2-ferrocenylethyne,25 and CpCo-
(23) Rybtchinski, B.; Konstantinovsky, L.; Shimon, L. J. W.; Vigalok, A.;
Milstein, D. Chem. Eur. J. 2000, 6, 3287.
(24) (a) Wurst, K.; Elsner, O.; Schottenberger, H. Synlett 1995, 833. (b)
Rodriguez, J. G.; On˜ate, A.; Martin-Villamil, R. M.; Fonseca, I. J.
Organomet. Chem. 1996, 513, 71. (c) Rosenblum, M.; Brawn, N.;
Papenmeier, J.; Applebaum, M. J. Organomet. Chem. 1966, 6, 173.
(25) Subramanian, R.; Karunatilaka, C.; Keck, K. S.; Kukolich, S. G. Inorg.
Chem. 2005, 44, 3137.
Inorganic Chemistry, Vol. 47, No. 17, 2008 7931

Xu et al.
Table 1. Crystallographic Data and Structure Refinement Information for 1, 2, 3, and 5
1
2
3
5
formula
formula weight
color
C4H20B20CoS4,C10H10Co
660.72
green
C14H20B10FeS2
416.39
yellow
C26H32B10Fe2S2
628.46
yellow
C10H20B10O4S2
376.50
white
size, mm
crystal system
space group
a, Å
b, Å
c, Å
0.24 × 0.26 × 0.30
0.24 × 0.26 × 0.30
orthorhombic
Pbcn
16.585(4)
16.254(4)
14.786(3)
90
0.24 × 0.26 × 0.30
0.24 × 0.26 × 0.30
triclinic
triclinic
triclinic
j
j
j
P1
P1
P1
7.153(4)
10.2696(12)
10.668(3)
14.0596(17)
74.060(2)
88.1300(10)
82.311(3)
1467.8(5)
2
10.028(3)
10.509(3)
11.515(4)
65.152(4)
84.841(5)
61.930(4)
962.8(5)
10.580(5)
11.339(8)
62.240(6)
82.802(10)
84.983(6)
753.0(8)
R (deg)
ꢀ (deg)
90
90
γ (deg)
V (Å3)
3985.9(16)
8
z
1
2
θ range (deg)
2.0-26.0
1.8-26.0
1.5-26.0
2.0-26.0
D(calc) [g/cm3]
1.457
1.388
1.422
1.299
µ (mm-1
)
1.389
0.962
1.149
0.288
min, max trans
data/restraints/parameters
F(000)
0.665, 0.715
2849/0/184
332
0.7612, 0.8019
3919/0/244
1696
0.7161, 0.7610
5642/0/361
644
0.9163, 0.9312
3699/0/237
388
no. reflns. collected
3913
20343
8056
5280
no. unique reflns. (Rint
GOF
)
2849 (0.024)
1.02
3919 (0.056)
1.01
5642 (0.023)
1.03
3699 (0.042)
0.97
R indices (I > 2σ(I))
R1 ) 0.0511
wR2 ) 0.1168
R1 ) 0.0619
wR2 ) 0.1198
0.497, -0.829
R1 ) 0.0499
wR2 ) 0.0970
R1 ) 0.0923
wR2 ) 0.1072
0.301, -0.228
R1 ) 0.0493
wR2 ) 0.1009
R1 ) 0.0652
wR2 ) 0.1045
0.296, -0.433
R1 ) 0.0469
wR2 ) 0.1204
R1 ) 0.0743
wR2 ) 0.1425
0.271, -0.203
R indices (all data)
largest diff. peak and hole
26
(CO)I2 were prepared by modified literature procedures. All
reactions were carried out under argon using standard Schlenk
techniques. All solvents were dried and deoxygenated prior to use.
Diethyl ether, tetrahydrofuran (THF), and petroleum ether toluene
were refluxed and distilled over sodium/benzophenone ketyl under
nitrogen. CH2Cl2 was refluxed and distilled over CaH2 under
nitrogen. The NMR measurements were performed on a Bruker
DRX 500 spectrometer. Chemical shifts were given with respect
HCdC). 11B{1H} NMR (CDCl3): δ -6.6 (3B), -6.0 (3B), -4.2
(2B), -1.6 (2B). 13C NMR (CDCl3): δ 67.02, 69.82, 70.48, 81.79
(Fc), 77.13, 112.29 (carborane), 112.36 (CHdC), 141.92 (dC-Fc).
EI-MS (70 eV): m/z 416 (M+, 100%). IR (KBr): ν (cm-1) 1633
(CdC), 2587 (B-H). Elemental analysis, calcd (%) for
C14H20B10Fe1S2: C 40.38, H 4.84; found: C 39.87, H 4.53. 3. Yellow
1
solid, yield 13 mg (10%), mp 183 °C dec. H NMR (CDCl3): δ
4.16 (s, 10H, Cp), 4.65 (m, 4H, Fc), 4.35 (m, 4H, Fc), 5.78 (s, 2H,
CdCH2), 6.13 (s, 2H, CdCH2). 13C NMR (CDCl3): δ 68.36, 69.82,
69.99, 84.26 (Fc), 93.52 (carborane), 124.99 (CdCH2), 139.31
(dC-Fc). 11B{1H} NMR (CDCl3): δ -8.7 (1B), -6.2 (7B), -0.6
to CHCl3/CDCl3 (δ H ) 7.24; δ 13C ) 77.0) and external Et2O-
1
BF3 (δ 11B ) 0). The IR spectra were recorded on a Bruker Vector
22 spectrophotometer with KBr pellets in the region of 4000-400
cm-1. The C and H microanalyses were carried out with Elemetar
Vario EL III elemental analyzer. The mass spectra (MS) was
recorded in a Micromass GC-TOF for EI-MS (70 ev).
(2B). EI-MS (70 eV): m/z 628 (M+, 21%). IR (KBr): ν (cm-1
)
1594 (FcCdCH2), 2575 (B-H). Elemental analysis: calcd (%) for
C26H32B10Fe2S2: C 49.69, H 5.13; found: C 49.17, H 5.44.
Preparation of 4. A mixture of 1 (66 mg, 0.1 mmol) and
phenylacetylene (0.22 mL, 2 mmol) in CH2Cl2 (20 mL) was stirred
for 24 h at ambient temperature. The color turned from green to
brown. After removal of the solvent, the residue was chromato-
graphed on TLC, and elution with petrol ether gave 4. White solid,
Preparation of 1. A solution of o-C2B10H12 (50 mg, 0.32 mmol)
in diethylether (10 mL) was lithiated by addition of a 2.0 M solution
of n-butyllithium (0.32 mL, 0.64 mmol) in hexanes. Then sulfur
(21 mg, 0.64 mmol) was added to the above mixture to generate
Li2S2C2B10H10 which reacted with CpCo(CO)I2 (120 mg, 0.30
mmol) in THF (20 mL) at 0 °C for 1 h. After removal of the
solvents the residue was chromatographed on silica. Elution with
CH2Cl2 gave 1. Green solid, yield 40 mg (40%). mp 210 °C dec.
1H NMR (CDCl3): δ 4.19 (s, Cp). 11B{1H} NMR (CDCl3): δ 1.5
(2B), -3.8 (1B), -4.8 (4B), -7.1 (2B), -9.3 (1B). ESI-MS: m/z
471 ([M - (Cp2Co)]+, 100%). IR (KBr): ν (cm-1) 2585 (B-H).
Elemental analysis: calcd (%) for C14H30B20Co2S4: C 25.45, H 4.58;
found: C 25.91, H 4.77.
1
yield 50 mg (81%). H NMR (CDCl3): δ 6.85 (s, 1H, CdCH),
7.41 (m, 3H, Ph), 7.47 (m, 2H, Ph). 13C NMR (CDCl3): δ 126.23,
129.09, 130.09, 136.35 (Ph), 118.46 (CHdC), 124.87 (dC-Ph).
11B{1H}NMR (CDCl3): δ -6.4 (3B), -5.1 (3B), -3.6 (2B), -1.2
(2B). EI-MS (70 eV): m/z 308.3 (M+, 100%). IR (KBr): ν (cm-1
)
1633 (CdCH), 2593 (B-H). Elemental analysis, calcd (%) for
C10H16B10S2: C 38.94, H 5.23; found: C 38.43, H 5.64.
Preparation of 5, 6, and 7. A mixture of 1(66 mg, 0.1 mmol)
and methyl acetylene monocarboxylate (0.17 mL, 2.0 mmol) in
CH2Cl2 (20 mL) was stirred for 24 h at ambient temperature. The
color turned from green to brown. After removal of the solvent,
the residue was chromatographed on TLC, and elution with petrol
ether/CH2Cl2 (1:1) gave 5, 6, and 7. 5. White solid, yield 23 mg
Preparation of 2 and 3. A mixture of 1 (66 mg, 0.1 mmol) and
ethynylferrocene (210 mg, 1.0 mmol) in CH2Cl2 (20 mL) was stirred
for 24 h at ambient temperature. The color turned from green to
yellow. After removal of the solvent the residue was chromato-
graphed on silica. Elution with petrol ether gave 2 and 3. 2. Yellow
1
1
solid, yield 58 mg (70%), mp 155 °C dec. H NMR (CDCl3): δ
4.21 (s, 5H, Cp), 4.45 (m, 2H, Fc), 4.40 (m, 2H, Fc), 6.53 (s, 1H,
(30%), mp 100 °C dec. H NMR (CDCl3): δ 3.76 (s, 3H, OMe),
6.02 (d, J ) 10 Hz, 1H, HCdCH-C(O)), 7.14 (d, J ) 10 Hz, 1H,
S-CHdCH). 13C NMR (CDCl3): δ 51.96, (OMe), 89.44 (carbo-
rane), 116.14 (HCdCH-C(O)), 144.33 (S-CHdCH), 166.53
(CdO). 11B{1H} NMR (CDCl3): δ -11.1 (2B), -8.2 (6B), -1.8
(26) (a) King, R. B. Inorg. Chem. 1966, 5, 82. (b) Frith, S. A.; Spencer,
J. L. Inorg. Synth. 1990, 28, 273.
7932 Inorganic Chemistry, Vol. 47, No. 17, 2008

Disulfuration and Hydrosulfuration of Alkynes
Table 2. Crystallographic Data and Structure Refinement Information for 6, 7, and 9
6
7
9
formula
formula weight
color
C10H20B10O4S2
376.50
white
C10H20B10O4S2
376.50
white
C14H22B10O8S2
490.56
white
size, mm
crystal system
space group
a, Å
b, Å
c, Å
0.24 × 0.26 × 0.30
0.24 × 0.26 × 0.30
monoclinic
C2/c
22.857(2)
13.6124(13)
13.2963(12)
90
106.9170(10)
90
3958.0(6)
8
0.24 × 0.26 × 0.30
monoclinic
C2/c
12.356(7)
12.873(7)
14.575(10)
90
93.926(12)
90
2313(2)
triclinic
j
P1
10.9663(10)
12.7759(12)
14.7343(14)
83.9590(10)
76.6780(10)
83.3300(10)
1988.6(3)
4
R (deg)
ꢀ (deg)
γ (deg)
V (Å3)
z
4
θ range (deg)
1.6-26.0
1.8-26.0
2.3-26.0
D(calc) [g/cm3]
1.258
1.264
1.409
µ (mm-1
)
0.279
0.280
0.273
min, max trans
data/restraints/parameters
F(000)
0.9163, 0.9312
7664/0/473
776
0.9163, 0.9312
3887/0/237
1552
0.9132, 0.9279
2261/0/156
1008
no. reflns. collected
10900
10609
6248
no. unique reflns. (Rint
GOF
)
7664 (0.061)
0.93
3887 (0.052)
1.09
2261 (0.053)
1.08
R indices (I > 2σ(I))
R1 ) 0.0478
wR2 ) 0.1156
R1 ) 0.0725
wR2 ) 0.1257
0.390, -0.229
R1 ) 0.0441
wR2 ) 0.1251
R1 ) 0.0628
wR2 ) 0.1351
0.357, -0.206
R1 ) 0.0528
wR2 ) 0.1206
R1 ) 0.0633
wR2 ) 0.1240
0.223, -0.353
R indices (all data)
largest diff. peak and hole
(2B). EI-MS (70 eV): m/z 376.1 (M+, 3%). IR (KBr): ν (cm-1
)
11B{1H} NMR (CDCl3): δ -9.5 (5B), -8.1 (2B), -5.2 (1B), -2.5
1633 (CdC), 1692 (CdO), 2572 (B-H). Elemental analysis, calcd
(%) for C10H20B10O4S2: C 31.90, H 5.35; found: C 32.53, H 5.89.
6. White solid, yield 21 mg (27%), mp 102 °C dec 1H NMR
(CDCl3): δ 3.78 (s, 3H, OMe), 3.79 (s, 3H, OMe), 6.04 (d, J ) 10
Hz, 1H, HCdCH-C(O)(Z)), 6.09 (d, J ) 16 Hz, 1H, HCd
CH-C(O)(E)), 7.14 (d, J ) 10 Hz, 1H, S-CHdCH (Z), 7.51 (d,
J ) 16 Hz, 1H, S-CHdCH (E)). 13C NMR (CDCl3): δ 52.06,
52.07 (OMe), 87.35, 89.29 (carborane), 116.31 (HCdCH-C(O)
(Z), 121.45 (HCdCH-C(O) (E)), 140.73 (S-CHdCH (E)), 144.33
(S-CHdCH (Z)), 164.14, 166.53 (CdO). 11B{1H} NMR (CDCl3):
δ -10.8 (2B), -8.3 (6B), -1.7 (2B). EI-MS (70 eV): m/z 376.2
(M+, 2%). IR (KBr): ν (cm-1) 1592 (CdC), 1699, 1724 (CdO),
2599 (B-H). Elemental analysis, calcd (%) for C10H20B10O4S2: C
31.90, H 5.35; found: C 32.64, H 5.76. 7. White solid, yield 26 mg
(2B). EI-MS (70 eV): m/z 490.0 (M+, 25%). IR (KBr): ν (cm-1
)
1741 (CdO), 2586 (B-H). Element analysis, calcd (%) for
C14H22B10O8S2: C 34.28, H 4.52; found C 33.76, H 4.83.
X-ray Crystallography. Crystals suitable for X-ray analysis were
obtained by slow evaporation of a solution in petroleum ether/
dicloromethene. Diffraction data were collected on a Bruker
SMART Apex II CCD diffractometer using graphite-monochro-
mated Mo KR (λ ) 0.71073Å) radiation at 273 K. During the
intensity data collection, no significant decay was observed. The
intensities were corrected for Lorentz-polarization effects and
empirical absorption with the SADABS program.27 The structures
were solved by direct methods using the SHELXL-97 program.28
All non-hydrogen atoms were found from the difference Fourier
syntheses. The H atoms were included in calculated positions with
isotropic thermal parameters related to those of the supporting
carbon atoms but were not included in the refinement. All
calculations were performed using the Bruker SMART program
(Tables 1 and 2).
1
(34%), mp 105 °C dec H NMR (CDCl3): δ 3.79 (s, 3H, OMe),
6.12 (d, J ) 16 Hz, 1H, HCdCH-C(O)), 7.50 (d, J ) 16 Hz, 1H,
S-CHdCH). 13C NMR (CDCl3): δ 52.15 (OMe), 87.31 (carbo-
rane), 121.61 (HCdCH-C(O)), 140.60 (S-CHdCH), 164.09
(CdO). 11B{1H} NMR (CDCl3): -10.8 (2B), -8.3 (6B), -1.6 (2B).
EI-MS (70 eV): m/z 376.2 (M+, 1%). IR (KBr): ν (cm-1) 1630
(CdC), 1725 (CdO), 2598 (B-H). Elemental analysis, calcd (%)
for C10H20B10O4S2: C 31.90, H 5.35; found: C 31.43, H 5.83.
Preparation of 8 and 9. A mixture of 1(66 mg, 0.1 mmol) and
dimethyl acetylenedicarboxylate (0.25 mL, 2.0 mmol) in CH2Cl2
(20 mL) was stirred for 24 h at ambient temperature. The color
turned from green to deep red. After removal of the solvent, the
residue was chromatographed on TLC, and elution with petrol ether/
CH2Cl2 (1: 2) gave 8, 9, and hexamethyl benzene-hexacarboxylate
(171 mg, 10%, based on dimethyl acetylenedicarboxylate used). 8.
White solid, yield 21 mg (30%). 1H NMR (CDCl3): δ 3.87 (s, 6H,
OMe). 13C NMR (CDCl3): δ 53.91 (OMe), 72.63 (carborane),
133.31 (C-C(O)), 162.18 (CdO). 11B{1H} NMR (CDCl3): δ -7.9
(5B), -5.7 (2B), -2.9 (3B). EI-MS (70 eV): m/z 348.1 (M+, 100%).
IR (KBr): ν (cm-1) 1568 (CdC), 1733 (CdO), 2593 (B-H).
Element analysis, calcd (%) for C8H16B10O4S2: C 27.58, H 4.63;
found: C 28.26, H 4.39. 9. White solid, yield 33 mg (30%), mp
Acknowledgment. This work was supported by National
Natural Science Foundation of China (20471017, 20771055,
90713023 and 20721002); The Major State Basic Research
Development Program of China (2006CB806104); National
Basic Research Program of China (2007CB925101); The
Natural Science Foundation of Jiangsu Province (BK2007131).
Supporting Information Available: X-ray crystallographic files
in CIF format for the compounds 1, 2, 3, 5, 6, 7, 9, the CheckCIF
and the 1H NMR spectra for 2 and 3 isolated from the reactions of
deuterated and nondeuterated FcCt CH with 1 for comparison. This
materialisavailablefreeofchargeviatheInternetathttp://pubs.acs.org.
IC801199E
(27) Sheldrick, G. M. SADABS, A Program for Empirical Absorption
Correction; University of Go¨ttingen: Go¨ttingen, Germany, 1998.
(28) Sheldrick, G. M. SHELXL-97, Program for the Refinement of Crystal
Structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
1
110 °C dec. H NMR (CDCl3): δ 3.86 (s, 6H, OMe), 3.95 (s, 6H,
OMe). 13C NMR (CDCl3): δ 53.83, 53.90 (OMe), 72.52 (carborane),
127.51 (CdC-C(O)), 151.35 (S-CdC), 162.04, 163.35 (CdO).
Inorganic Chemistry, Vol. 47, No. 17, 2008 7933