Sn-S and Ru-Ru bonds cleavage reactions between [Ph3SnS(CH2)3SSnPh3] and Ru3(CO)12: X-ray crystal structures of [Ph3SnS(CH2)3SSnPh3] and trans-[R

Article abstract of DOI:10.1016/j.ica.2009.05.011

The organotin complex [Ph₃SnS(CH₂)₃SSnPh₃] (1) was synthesized by PdCl₂ catalyzed reaction between Ph₃SnCl and disodium-1,3-propanedithiolate which in turn was prepared from 1,2-propanedith

Full text of DOI:10.1016/j.ica.2009.05.011

Inorganica Chimica Acta 362 (2009) 4226–4230
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Note
Sn–S and Ru–Ru bonds cleavage reactions between [Ph3SnS(CH2)3SSnPh3]
and Ru3(CO)12: X-ray crystal structures of [Ph3SnS(CH2)3SSnPh3]
and trans-[Ru(CO)4(SnPh3)2]
b,
Shishir Ghosh a, Rehana Pervin a, Arun K. Raha a, Shariff E. Kabir a, , Brian K. Nicholson
*
*
a Department of Chemistry, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh
b Department of Chemistry, University of Waikato, Hamilton, New Zealand
a r t i c l e i n f o
a b s t r a c t
Article history:
The organotin complex [Ph3SnS(CH2)3SSnPh3] (1) was synthesized by PdCl2 catalyzed reaction between
Ph3SnCl and disodium-1,3-propanedithiolate which in turn was prepared from 1,2-propanedithiol and
sodium in refluxing THF. Reaction of 1 with Ru3(CO)12 in refluxing THF affords the mononuclear complex
Received 7 March 2009
Received in revised form 30 April 2009
Accepted 5 May 2009
trans-[Ru(CO)4(SnPh3)2] (2) and the dinuclear complex [Ru2(CO)6(l-j
2-SCH2CH2CH2S)] (3) in 20 and 11%
Available online 14 May 2009
yields, respectively, formed by cleavage of Sn–S bond of the ligand and Ru–Ru bonds of the cluster. Treat-
ment of pymSSnPPh3 (pymS = pyrimidine-2-thiolate) with Ru3(CO)12 at 55–60 °C also gives 2 in 38%
yield. Both 1 and 2 have been characterized by a combination of spectroscopic data and single crystal
X-ray diffraction analysis.
Keywords:
Ph3SnS(CH2)3SSnPh3
Trirutheniumdocacarbonyl
Sn–S bond cleavage
Triphenyltin
Ó 2009 Elsevier B.V. All rights reserved.
X-ray structures
1. Introduction
cently reported some unusual bimetallic Ru–Sn, Ru–Ge clusters,
e.g. [Ru3(CO)8(
SPh)2( 3-GePh2)(GePh3)2], from the reactions of Ph3SnSPh or
Ph3GeSPh with Ru3(CO)12, respectively (Scheme 1) [20]. We also
reported the Os–Sn compound [Os3(CO)9( -SPh)( 3-SnPh2)-
(NCMe)(
1-C6H5)2] from the reaction of [Os3(CO)10(NCMe)2] with
Ph3SnSPh [21]. Given the potential of dithioorganotin compounds
in the synthesis of triruthenium clusters containing bridging
dithiolato and SnPh2 ligands we have performed the synthesis of
Ph3SnS(CH2)3SSnPh3. This paper provides an account of the
synthesis, structure and reactivity of this ligand with
l-SPh)2(l3-SnPh2)(SnPh3)2] and [Ru3(CO)8(l-
Organotin complexes have become versatile reagents in organ-
ic and organometallic chemistry [1]. Ruthenium compounds de-
rived from metal carbonyl cluster complexes combined with
group 14 elements have been found to exhibit interesting cata-
lytic properties [2–4]. The coordination of SnR3 fragments to tri-
metallic clusters of ruthenium and osmium by oxidative
addition of Sn–H bond of R3SnH to give many interesting com-
pounds is well documented [5–8]. It has recently been demon-
strated that coordinated SnPh3 is an excellent ligand for the
introduction of SnPh2 ligands to polynuclear metal carbonyl com-
plexes [9–12]. On the other hand, the introduction of thiolato
group in trimetallic clusters by oxidative addition of S–H bond
of thiols is well established [13–19]. Recently, aminostannanes
have been shown to react with transition metal hydride com-
plexes to form metal–metal bonds and taking the advantage of
this methodology, Garate-Morales and Fernandez-G have synthe-
sized amine-containing osmium–tin compounds [Os3(CO)10
l
l
l
g
Ru3(CO)12
.
2. Experimental
All reactions were carried out under a nitrogen atmosphere. Re-
agent grade solvents were dried using appropriate drying agents
and were freshly distilled prior to use. Ru3(CO)12 was purchased
from Strem Chemicals Inc. and used without further purification.
Infrared spectra were recorded on a Shimadzu FTIR 8101 spectro-
photometer. 1H NMR spectra was recorded on a Bruker DPX 400
instrument. All chemical shifts are reported in d units with refer-
ence to the residual protons of the deuterated solvents. Electro-
(HE)(SnBu3)(l-H)] (HE = amine) [20]. The organotin and thiolato
fragments in organic compounds can be incorporated into organo-
metallic cluster compounds resulting in the formation of M–Sn
and M–S bonds (M = Os, Ru) and in this context, we have very re-
spray mass spectra were recorded on
a Bruker MicrOTof
machine, using MeOH as solvent and NaOMe added as an ionisa-
tion aid [22]. The compound pymSSnPPh3 was prepared according
to the literature procedure [23].
* Corresponding authors.
E-mail addresses: skabir_ju@yahoo.com (S.E. Kabir), b.nicholson@waikato.ac.nz
(B.K. Nicholson).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.05.011

S. Ghosh et al. / Inorganica Chimica Acta 362 (2009) 4226–4230
4227
SPh
PhS
(CO)2
Ru
80 oC
Ru3(CO)12
+
Ph3XSPh
Ph3X Ru
(CO)3
Ru XPh3
(CO)3
X
Ph2
(X = Sn, Ge)
Scheme 1. Reaction of Ru3(CO)12 with Ph3XSPh (X = Sn, Ge).
2.1. Preparation of [Ph3SnS(CH2)3SSnPh3] (1)
[M+OMe]À (calc. 944.943). The third band afforded [Ru2(CO)6(
l-
j
2-SCH2CH2CH2S)] (3) (8 mg, 11%) as pale yellow crystals after
A mixture of 1,3-propanedithiol (243 mg, 2.25 mmol) and Na
(103 mg, 4.51 mmol) in THF (40 mL) was heated to reflux for 4 h
during which time all the Na reacted. To this was added dropwise
a THF solution (10 mL) of Ph3SnCl (1736 mg, 2.25 mmol) at 0 °C
followed by 10 mg of PdCl2 and the mixture was slowly warmed
to room temperature and stirred overnight. After filtering the mix-
ture, the filtrate was evaporated to dryness and the residue chro-
matographed by TLC on silica gel. Elution with hexane/CH2Cl2
afforded [Ph3SnS(CH2)3SSnPh3] (1) (600 mg, 34%) as colorless crys-
tals from EtOH/THF at 4 °C. Anal. Calc. for C39H36S2Sn2: C, 58.11; H,
4.51. Found: C, 58.33; H, 4.59%. 1H NMR (CDCl3): d 2.55 (t, 4H,
J = 6.8 Hz), 1.70 (q, 2H, J = 6.8 Hz), 7.59 (m, 10H), 7.38 (m, 20H).
ESI-MS: m/z 1155.048 [M+Ph3Sn]+ (calc. 1155.050); m/z 829.022
[M+Na]+ (calc. 829.020).
recrystallization from hexane/CH2Cl2 at 4 °C. IR (mCO, hexane):
2086 s, 2055 vs, 2018 vs, 2004 s, 1994 s, 1966 w cmÀ1 1H NMR
.
(CDCl3): d 2.20 (m, 4H), 1.91 (m, 2H).
2.3. Preparation of pyrimidine-2-thiotriphenyltin, pymSSnPh3
KOH (51 mg, 0.91 mmol) was added to a C2H5OH solution
(20 mL) of 2-mercaptopyrimidine (100 mg, 0.89 mmol) and the
reaction mixture was stirred for 30 min at room temperature.
The color of the solution slowly changed from orange to colorless.
Then Ph3SnCl (343 mg, 0.89 mmol) was added to the reaction mix-
ture and stirred for further 30 min at room temperature. The solu-
tion was filtered through a filter paper. The solvent was removed
under reduced pressure and the residue chromatographed by TLC
on silica gel. Elution with CH2Cl2 developed one band which affor-
ded pymSSnPh3 (280 mg, 68%) as colorless crystals from hexane/
CH2Cl2 at 4 °C. 1H NMR (CDCl3): d 8.28 (d, J = 4.8 Hz, 2H), 7.76–
7.59 (m, 6H), 7.37 (m, 9H), 6.85 (t, J = 4.8 Hz, 1H).
2.2. Reaction of Ru3(CO)12 with 1
A THF solution (20 mL) of Ru3(CO)12 (100 mg, 0.15 mmol) and 1
(126 mg, 0.156 mmol) was heated to reflux for 3 h. The solvent was
removed by rotary evaporation and the residue chromatographed
by TLC on silica gel. Elution with hexane/CH2Cl2 (7:3, v/v) devel-
oped three bands. The first band was unreacted Ru3(CO)12 (trace).
The second band gave trans-[Ru(CO)4(SnPh3)2] (2) (28 mg, 20%) as
colorless crystals after recrystallization from hexane/CH2Cl2 at
4 °C. Anal. Calc. for C40H30O4RuSn2: C, 52.62; H, 3.32. Found: C,
2.4. Reaction of Ru3(CO)12 with pymSSnPh3
A mixture of Ru3(CO)12 (100 mg, 0.016 mmol) and pymSSnPh3
(148 mg, 0.32 mmol) in THF (25 mL) was heated for 5 h at 55–
60 °C. The solvent was removed under reduced pressure and the
residue separated by TLC on silica gel. Elution with hexane/CH2Cl2
(7:3 v/v) developed three bands. The first band gave unreacted
Ru3(CO)12 (20 mg). The second band afforded 2 (41 mg, 38%) as
52.86; H, 3.38%. IR (m .
CO, CH2Cl2): 2032 vs cmÀ1 1H NMR (CDCl3):
d 7.62–7.49 (m, 12H), 7.37–7.34 (m, 18H). ESI-MS: m/z 944.948
Table 1
Crystallographic data and structure refinement for 1, 2a, 2b and 2c.
1
2a and 2b
2cÁC2H4Cl2
Empirical formula
Formula weight (Å)
Temperature (K)
Crystal system
C39H36S2Sn2
806.18
89(2)
monoclinic
P21/c
C40H30O4RuSn2
913.09
90(2)
monoclinic
C2/c
C40H30O4RuSn2ÁC2H4Cl2
1012.04
90(2)
monoclinic
P21/n
Space group
Unit cell dimensions
a (Å)
b (Å)
c (Å)
12.9769(1)
14.8376(2)
18.9431(2)
106.533(1)
3496.62(7)
4
1.531
1.574
33.5198(5)
9.1535(1)
26.0496(4)
117.403(1)
7095.78(17)
8
1.709
1.857
3568
8.4910(1)
11.8888(1)
19.8906(2)
100.821(1)
1972.21(4)
2
1.704
1.810
992
b (°)
V (Å3)
Z
Density (calculated) (Mg/m3)
Absorption coefficient (mmÀ1
F(0 0 0)
)
1608
Crystal size (mm)
h Range for data collection (°)
Reflections collected
0.34 Â 0.23 Â 0.23
1.77–36.30
42 758
0.30 Â 0.20 Â 0.15
1.37–27.97
82 690
0.32 Â 0.20 Â 0.10
2.01–27.91
24 013
Independent reflections
Data/restraints/parameters
Goodness-of-fit (GOF) on F2
15 714 [Rint = 0.0280]
15 714/0/388
1.043
8522 [Rint = 0.0308]
8522/0/427
1.037
4712 [Rint = 0.0449]
4712/0/232
1.026
Final R indices [I > 2
R indices (all data)
r
(I)]
R1 = 0.0289, wR2 = 0.0586
R1 = 0.0465, wR2 = 0.0630
0.899 and À0.611
R1 = 0.0198, wR2 = 0.0494
R1 = 0.0247, wR2 = 0.0520
0.899 and À0.444
R1 = 0.0261, wR2 = 0.0531
R1 = 0.0376, wR2 = 0.0569
0.610 and À0.409
Largest difference in peak and hole (e ÅÀ3
)

4228
S. Ghosh et al. / Inorganica Chimica Acta 362 (2009) 4226–4230
66 oC
Na
Ph3SnCl
PdCl2
SnPh3
SnPh3
S
SH
SNa
SNa
SH
S
1
Scheme 2. Synthesis of Ph3SnS(CH2)3SSnPh3.
colorless crystals after recrystallization from hexane/C2H4Cl2 at
4 °C. The third band was too small for complete characterization.
TEP diagram of the molecular structure of 1 is depicted in Fig. 1,
and selected bond distances and angles are listed in the caption.
The molecule contains two SSnPPh3 units linked by a CH2CH2CH2
chain. The molecule possesses a non-crystallographic two-fold axis
of symmetry passing through the C(2) carbon. Both tin atoms are
four coordinated and adopt a distorted tetrahedral geometry. The
average C–Sn–C angle {112.81(5)° for Sn(1) and 111.80(5)° for
Sn(2)} is greater than 109.5° (in the idealized polyhedron) while
the average C–Sn–S angle {105.83(4)° for Sn(1) and 107.04(4)°
for Sn(2)} is smaller at both tin centres, as expected on steric argu-
2.5. X-ray crystallography
Single crystals were mounted on fibres and diffraction data col-
lected at low temperatures (see Table 1) on a Bruker APEX II CCD
diffractometer using Mo Ka radiation (k = 0.71073 Å). Data collec-
tion, indexing and initial cell refinements were all done using SMART
[24] software. Data reduction was done with SAINT [25] software
and the SADABS program [26] was used to apply empirical absorption
corrections. The structures were solved by direct methods [27] and
refined by full matrix least-squares on F2. All non-hydrogen atoms
were refined anisotropically and hydrogen atoms were included
using a riding model. Crystal data and refinement details are sum-
marized in Table 1.
ments. The two Sn–S bond distances in
1 are equal [av.
2.4084(3) Å] and are towards the shorter end of the range reported
in literature for Sn–S bonds [28,29]. Molecules are linked in the
crystal by centrosymmetric, reciprocal ortho-C–HÁ Á ÁS hydrogen-
bonds, HÁ Á ÁS distances 2.9 Å.
3.2. Reactions of Ru3(CO)12 with 1 and pymSSnPh3
3. Results and discussion
Treatment of Ru3(CO)12 with 1 at 66 °C furnishes trans-[Ru(-
CO)4(SnPh3)2] (2) and [Ru2(CO)6(l-j
2-SCH2CH2CH2S)] (3) in 20
3.1. Synthesis and molecular structure of [Ph3SnS(CH2)3SSnPh3] (1)
and 11% yields, respectively, whereas the reaction between
Ru3(CO)12 and pymSSnPh3 at 50–60 °C predominantly gives 2 in
38% yield (Scheme 3).
The nucleophilic substitution reaction between triphenyltin
chloride and disodium-1,3-propanedithiolate in the presence of
PdCl2, followed by usual workup and chromatographic separation,
affords [Ph3SnS(CH2)3SSnPh3] (1) in 34% yield (Scheme 2). Appar-
ently PdCl2 catalyzes the formation of 1 as attempts to obtain 1
by the same procedure in the absence of PdCl2 failed.
The dinuclear compound 3 was previously reported by us ob-
tained from the reaction between Ru3(CO)12 with 1,3-propanedi-
thiol [30]. Compound 2 was first described many years ago, from
reactions of Ph3SnH with Ru3(CO)12 [31], from Ph3SnCl and
2À
The aliphatic region of the 1H NMR spectrum of 1 shows a trip-
let at d 2.55 (J = 6.8 Hz; integrated to 4H) and a quintet at d 1.70
(J = 6.8 Hz, integrated to 2H) while the aromatic region contains
two multiplets at d 7.59 and 7.38 with a relative intensity of
10:20 confirming the formulation of 1. We were able to grow sin-
gle crystals of 1 and undertook a solid-state investigation. An OR-
H2Ru3(CO)12 [32] or from Ph3SnCl and Ru(CO)4 [33]. Very re-
cently it was also isolated from the reaction between Ph3SnH and
[Ru3(CO)10(CNMe)2] [8,34]. The iron analogue of 2 was reported
by Graham et al. obtained from the reaction of Na2Fe
(CO)4Á1.5C4H8O2 and Ph3SnCl at À78 °C [35] while the osmium
analogue was reported by Collman et al. synthesized from the reac-
tion between Na2[Os(CO)4] and Ph3SnCl at À78 °C and also from
H2Os(CO)4 and Ph3SnCl at room temperature [36]. The iron and os-
mium analogues of compound 2 have been structurally character-
ized in detail, while the structure of 2 itself has been very recently
reported, without discussion, in a triclinic form as the benzene
solvate [34]. It is interesting to note that the iron complex has a
cis-configuration whereas the osmium complex possesses trans-
configuration. The Ph3Ge analogue of 2, [Ru(CO)4(GePh3)2], is also
found in trans-configuration [37] whereas [Ru(CO)4(GeCl3)2] has
been shown to exist in both cis and trans-configuration [38].
We have crystallised compound 2 from two different solvent
systems, hexane/dichloromethane (CH2Cl2) or hexane/1,2-dichlo-
roethane (C2H4Cll2) and obtained two crystalline modifications:
monoclinic (C2/c) from CH2Cl2 and monoclinic (P21/n) from
C2H4Cl2. Both forms were investigated by single crystal X-ray dif-
fraction analyses for comparison with the earlier triclinic version.
The C2/c form contains two independent molecules (2a and 2b)
in the asymmetric unit, each lying on an inversion centre. The bond
lengths and bond angles in both molecules are very similar and an
ORTEP diagram of 2a is shown in Fig. 2, with selected bond dis-
tances and angles listed in the caption. The P21/n form contains a
C2H4Cl2 solvent molecule in the unit cell in addition to a molecule
of 2 (2c), both of which lie on crystallographic inversion centres. In
each case, as well as in the previous triclinic version, compound 2
Fig. 1. Molecular structure of [Ph3SnS(CH2)3SSnPPh3] (1) showing 35% probability
thermal ellipsoids. Selected bond distances (Å) and angles (°): Sn(1)–S(1) 2.4077(3),
Sn(2)–S(2) 2.4091(3), C(1)–S(1) 1.8319(14), C(3)–S(2) 1.8360(14), C(1)–C(2)
1.5234(17), C(2)–C(3) 1.5217(18), av. Sn(1)–C 2.1310(13), av. Sn(2)–C 2.1292(13),
C(1)–S(1)–Sn(1) 102.99(4), C(3)–S(2)–Sn(2) 100.09(4), av. C–Sn(1)–C 112.81(5), av.
C–Sn(1)–S(1) 105.83(4), av. C–Sn(2)–C 111.80(5), av. C–Sn(2)–S(2) 107.04(4), C(2)–
C(1)–S(1) 108.80(9), C(2)–C(3)–S(2) 109.96(9), C(3)–C(2)–C(1) 114.90(12).

S. Ghosh et al. / Inorganica Chimica Acta 362 (2009) 4226–4230
4229
pymSSnPh3
Ru3(CO)12
55-60 oC
+
SnPh3
S
S
OC
66 oC
CO
+
Ru(CO)3
Ru3(CO)12
+
1
Ru
(OC)3Ru
OC
Ph3Sn
CO
3
2
Scheme 3. Reactions of Ru3(CO)12 with Ph3SnS(CH2)3SSnPh3 and pymSSnPh3.
cis example amongst the now complete series (Ph3Sn)2M(CO)4
may suggest that -bonding is more important in the Sn–Fe bond
p
than in the Sn–Ru or Sn–Os ones. NMR studies which show that
there is facile cis–trans isomerism in solution for these complexes
suggest that energy differences are small [41].
Acknowledgement
A. K. R. gratefully acknowledges the University Grants Commis-
sion of Bangladesh for a scholarship.
Appendix A. Supplementary material
CCDC 711279, 711277, and 711278 contain the supplementary
crystallographic data for 1, 2 (2a and 2b) and 2 (2c), respectively.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_re-
quest/cif.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.ica.2009.05.011.
Fig. 2. Molecular structure of trans-[Ru(CO)4(SnPh3)2] (2c) showing 35% probability
thermal ellipsoids. Selected bond distances (Å) and angles (°): Sn(1)–Ru(1)
2.69558(14), Sn(1)#–Ru(2) 2.2.69558(14), Ru(1)–C(11) 1.943(2), Ru(1)–C(11)#1
1.943(2), Ru(1)–C(12) 1.950(2), Ru(1)–C(12)#1 1.950(2), C(11)–O(11) 1.130(3),
C(12)–O(12) 1.135(3), Sn(1)–C 2.153(2), Sn(1)–Ru(1)–Sn(1)#1 180.000(5), C(11)–
Ru(1)–C(11)#1 180.0(3), C(12)–Ru(1)–C(12)#1 180.0(15), av. C–Ru(1)–C 90.00(9),
av. C–Ru(1)–Sn(1) 90.00(6), av. C–Ru(1)–Sn(1)#1 90.00(6).
References
[1] A.G. Davies, Organotin Chemistry, 2nd ed., Wiley-VCH, 2004.
[2] S. Hermans, B.F.G. Johnson, R. Raja, J.M. Thomas, G. Sankar, D. Gleeson, Angew.
Chem. Int. Ed. 40 (2001) 1211.
[3] R. Raja, T. Khimyak, J.M. Thomas, S. Hermans, B.F.G. Johnson, Angew. Chem. Int.
Ed. 40 (2001) 4638.
[4] S. Hermans, B.F.G. Johnson, Chem. Commun. (2000) 1955.
[5] K. Burgess, C. Guerin, B.F.G. Johnson, J. Lewis, J. Organomet. Chem. 295 (1985)
C3.
[6] W.K. Leong, R.K. Pomeroy, R.J. Batchelor, F.W.B. Einstein, C.F. Campana,
Organometallics 15 (1996) 1582.
[7] R.J. Hall, P. Serguievski, J.B. Keister, Organometallics 19 (2000) 4499.
[8] R.D. Adams, B. Captain, E. Trufan, J. Organomet. Chem. 693 (2008) 3593.
[9] R.D. Adams, B. Captain, W. Fu, M.D. Smith, Inorg. Chem. 41 (2002) 5593.
[10] R.D. Adams, B. Captain, J.L. Smith Jr., M.B. Hall, C.L. Beddie, C.E. Webster, Inorg.
Chem. 43 (2004) 7576.
[11] R.D. Adams, B. Captain, W. Fu, M.D. Smith, Inorg. Chem. 41 (2002) 2302.
[12] R.D. Adams, B. Captain, L. Zhu, Inorg. Chem. 44 (2005) 6623.
[13] G.R. Crooks, B.F.G. Johnson, J. Lewis, I.G. Williams, J. Chem. Soc. A (1969) 797.
[14] S.R. Hodge, B.F.G. Johnson, J. Lewis, P.R. Raithby, J. Chem. Soc., Dalton Trans.
(1987) 931.
[15] K.A. Azam, S.E. Kabir, A. Miah, M.W. Day, K.I. Hardcastle, E. Rosenberg, A.J.
Deeming, J. Organomet. Chem. 435 (1992) 157.
[16] P. Fompeyrine, G. Lavigne, J.J. Bonnet, J. Chem. Soc., Dalton Trans. (1987) 91.
[17] S.M.T. Abedin, K.A. Azam, M.B. Hursthouse, S.E. Kabir, K.M.A. Malik, M.A.
Mottalib, E. Rosenberg, J. Cluster Sci. 12 (2001) 5.
[18] S.E. Kabir, K.M.A. Malik, E. Mollah, M.A. Mottalib, J. Organomet. Chem. 616
(2000) 157.
[19] S.E. Kabir, C.A. Johns, K.M.A. Malik, M.A. Mottalib, E. Rosenberg, J. Organomet.
Chem. 625 (2001) 112.
contains a single ruthenium atom ligated by four CO and two
SnPPh3 ligands. The SnPh3 ligands are trans to each other with
the Sn–Ru–Sn angle being exactly 180° by symmetry constraints
(in for the monoclinic forms) compared with 172.1° for the triclinic
form 2d. The Ru–Sn bond distances in 2 {2.6956(2) Å in 2a; 2.6982
(2) Å in 2b; 2.6892 (2) Å in 2c;} are within the range found in liter-
ature [21,39], though marginally shorter than found for 2d
(2.709 Å). These values compare with the Sn–Os bond length of
2.712(1) Å in the osmium analogue of 2 [32]. The average Sn–
Ru–C and C–Ru–C angles between cis-positioned ligands are 90°
in both monoclinic forms but the SnRuSn axis is ꢀ1.5° tilted with
respect to the Ru(CO)4 plane.
The 1H NMR spectrum of 2 displays only aromatic resonances
while the infrared spectrum shows only one very intense band,
consistent with the solid-state geometry.
There is still no clear explanation for the distribution of cis and
trans isomers of (R3E)2M(CO)4 as E (Si, Ge, Sn) and M (Fe, Ru, Os)
vary. The trans isomer must be favoured sterically, whereas the
cis isomer would be preferred on electronic grounds for purely
[20] J.L. Garate-Morales, J.M. Fernandez-G, Organometallics 23 (2004) 3840.
[21] S.E. Kabir, A.K. Raha, M.R. Hassan, B.K. Nicholson, E. Rosenberg, A. Sharmin, L.
Salassa, J. Chem. Soc., Dalton Trans. (2008) 4212.
[22] W. Henderson, J.S. McIndoe, B.K. Nicholson, P.J. Dyson, J. Chem. Soc., Dalton
Trans. (1998) 519.
r
-bonded R3E groups [40]. The surprising observation that it is
the example with the smallest metal atom, Fe, that provides the

4230
S. Ghosh et al. / Inorganica Chimica Acta 362 (2009) 4226–4230
[23] E.W. Abel, D.B. Brady, J. Chem. Soc. (1965) 1192.
[33] J.D. Cotton, S.A.R. Knox, F.G.A. Stone, Chem. Commun. (1967) 965.
[34] R.D. Adams, D.A. Blom, B. Captain, R. Raja, J.M. Thomas, E. Trufan, Langmuir 24
(2008) 9223.
[35] R.K. Pomeroy, L. Vancea, H.P. Calhoun, W.A.G. Graham, Inorg. Chem. 16 (1977)
1508.
[36] J.P. Collman, D.W. Murphy, E.B. Fleischer, D. Swift, Inorg. Chem. 13 (1974) 1.
[37] R.D. Adams, B. Captain, E. Trufan, J. Cluster Sci. 18 (2007) 642.
[38] R. Ball, M.J. Bennett, Inorg. Chem. 11 (1972) 1806.
[39] C.J. Cardin, D.J. Cardin, M.A. Convery, Z. Dauter, D. Fenske, M.M. Devereux, M.B.
Power, J. Chem. Soc., Dalton Trans. (1996) 1133.
[40] D.W. Smith, J. Chem. Soc., Dalton Trans. (1976) 834.
[41] L. Vancea, R.K. Pomeroy, W.A.G. Graham, J. Am. Chem. Soc. 98 (1976)
1407.
[24] SMART Version 5.628, Bruker AXS Inc., Madison, WI, 2003.
[25] SAINT Version 6.36, Bruker AXS Inc., Madison, WI, 2002.
[26] G. Sheldrick, SADABS Version 2.10, University of Göttingen, 2003.
[27] G. Sheldrick, SHELX-97, Program for Crystal Structure Determination, University
of Gottingen, Gottingen, 1997.
[28] L.-S. Wang, T.-L. Sheng, J.-J. Zhang, S.-M. Hu, R.-B. Fu, X.-T. Wu, Y.-M. Li, X.-H.
Huang, S.-C. Xiang, Polyhedron 26 (2007) 1098.
[29] Zia-ur-Rehman, S. Shahzadi, S. Ali, G.-X. Jin, Turk. J. Chem. 31 (2007) 435.
[30] K.M. Hanif, S.E. Kabir, M.A. Mottalib, M.B. Hursthouse, K.M.A. Malik, E.
Rosenberg, Polyhedron 19 (2000) 1073.
[31] J.D. Cotton, M.I. Bruce, F.G.A. Stone, J. Chem. Soc. A (1968) 2162.
[32] J.D. Cotton, S.A.R. Knox, F.G.A. Stone, J. Chem. Soc. A (1968) 2758.