The structural chemistry of organotin derivatives of 5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thione: Supramolecular structures involving intermolecular Sn···S, N-H···S or S···S interactions

Article abstract of DOI:10.1039/b109726a

Seven new organotin complexes of 5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thione (I), R_nSn(PhN₂C₂S₃)_{4 - n} [n = 1, R = Bu (1); n = 2, R = Ph (2), Bu (3), Me (4) and n = 3, R = Ph (5), Bu (6), Me (7)], along with the 4,4′-bipy and 4-PyNH₂ adducts of 7, [Me₃Sn(PhN₂C₂S₃)] ₂·(4,4′-bipy) (8) and [Me₃Sn(4-PyNH₂)₂]⁺[PhN ₂C₂S₃]^- (9), respectively, have been synthesised. The coordination behaviour of I in 1-8 ranges from S(1) monodentate to S(1) + S(3) bidentate bridging, while the crystal structure of 9 contains the ligand as a non-bonded anion. The supramolecular structures of 2, 7 and 8 have been found to consist of 1-D molecular chains built up by Sn···S (7) or S···S (2,8) intermolecular linkages. Additionally, the 1-D polymers of 7 aggregate in 'ribbon'-type double chains through S···S interactions and further self-organise via Ph···Ph face-to-face π-stacking, leading to a 3-D network. Extended intermolecular N-H···S interactions in the crystal lattice of 9 link the molecules in a 3-D network.

Full text of DOI:10.1039/b109726a

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The structural chemistry of organotin derivatives of 5-mercapto-
3-phenyl-1,3,4-thiadiazoline-2-thione: supramolecular structures
involving intermolecular Sn ؒ ؒ ؒ S, N–H ؒ ؒ ؒ S or S ؒ ؒ ؒ S
interactions†
Vasile Berceanc,a Crina Crainic,b Ionel Haiduc,b Mary F. Mahon,c Kieran C. Molloy,c
Monica M. Venter*b,c and Paul J. Wilsonc
a Department of Chemistry, Technical University of Timisoara, RO-1900 Timisoara, Romania
b Department of Chemistry, “Babes-Bolyai” University of Cluj, RO-3400 Cluj-Napoca,
Romania
c Department of Chemistry, University of Bath, Bath, UK BA2 7AY
Received 24th October 2001, Accepted 25th January 2002
First published as an Advance Article on the web 19th February 2002
Seven new organotin complexes of 5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thione (I), RnSn(PhN2C2S3)4 Ϫ n [n = 1,
R = Bu (1); n = 2, R = Ph (2), Bu (3), Me (4) and n = 3, R = Ph (5), Bu (6), Me (7)], along with the 4,4Ј-bipy and
4-PyNH2 adducts of 7, [Me3Sn(PhN2C2S3)]2ؒ(4,4Ј-bipy) (8) and [Me3Sn(4-PyNH2)2]ϩ[PhN2C2S3]Ϫ (9), respectively,
have been synthesised. The coordination behaviour of I in 1–8 ranges from S(1) monodentate to S(1) ϩ S(3) bidentate
bridging, while the crystal structure of 9 contains the ligand as a non-bonded anion. The supramolecular structures
of 2, 7 and 8 have been found to consist of 1-D molecular chains built up by Sn ؒ ؒ ؒ S (7) or S ؒ ؒ ؒ S (2, 8)
intermolecular linkages. Additionally, the 1-D polymers of 7 aggregate in ‘ribbon’-type double chains through
S ؒ ؒ ؒ S interactions and further self-organise via Ph ؒ ؒ ؒ Ph face-to-face π-stacking, leading to a 3-D network.
Extended intermolecular N–H ؒ ؒ ؒ S interactions in the crystal lattice of 9 link the molecules in a 3-D network.
Introduction
We have an on-going interest in tin–sulfur chemistry, partly
from the aspect of materials science, where we have investigated
precursors for the deposition of tin sulfides,1–3 and also because
of the supramolecular assemblies which can be formed from
such species.4,5 It is the latter which forms the focus of this
paper.
suggested, despite the lack of any conclusive crystallographic
Supramolecular organometallic chemistry is a topical aspect
support.16–18 To our knowledge, very few organotin derivatives
of I have been studied and no structural characterisations of
such species have been reported so far.19
of current research.6 Our contributions to date have included
the coordination behaviour of five- and six-membered thiol/
thione heterocycles, and, specifically, the structures of their
organotin and lead complexes.4,5,7 For example, organotin-
substituted tetrazole thiolates are known to adopt monomer,7,8
trimer,9 polymer10 and sheet4 structures, all containing σ-Sn–
ligand bonds. In contrast, Ph3PbSCN4Ph has an intriguing
lattice arrangement in which a tetrazole appears to approach a
neighbouring lead in a π-coordinating manner.11 Moreover, we
have lately become interested in well-known analytical reagents
as potential donors (e.g. trithiocyanuric acid), as very little is
known of the synthesis and/or structural characterisation of
their organometallic complexes.
The aim of this work was to elucidate the structures
of new organotin derivatives of 5-mercapto-3-phenyl-1,3,4-
thiadiazoline-2-thione (I) (also referred to in older literature as
Bismuthiol II). Compound I, which can exist in either thiol (Ia)
or thione (Ib) forms, has been intensively investigated as a
precipitating agent12–15 and its industrial importance has also
been noted.16
Ligands such as I also present a number of opportunities for
creating supramolecular arrangements. In addition to inter-
molecular bridging from Lewis base sites (either nitrogen or
sulfur) and/or potential H-bonding from inclusion of solvents
such as water or alcohol, the presence of a plethora of sulfur
atoms can also gives rise to S ؒ ؒ ؒ S interactions. Among the
explosion of studies involving crystal engineering in recent
years, these S ؒ ؒ ؒ S interactions, being the weakest of the three
classes listed above, have been largely ignored, save for those
involving tetrathiafulvalene (TTF) and its analogues.20 Such
planar, sulfur-rich species are central to a large number of
charge-transfer organic metals, and although π-stacking of
planar donors and acceptors is the key structural feature in
their one-dimensional conductivity, weak intermolecular
S ؒ ؒ ؒ S interactions often reduce this electronic anisotropy to
two-dimensions. We herein report the role of each of the three
lattice building strategies, including S ؒ ؒ ؒ S bonding, in the
supramolecular chemistry of the organotin derivatives of I.
The synthesis and spectral characterisation of some trans-
ition metal complexes of Bismuthiol II and related heterocycles
(e.g. Bismuthiol I) has been carried out previously and S(1) ϩ
S(3) bidentate bridging coordination by the ligand has been
Results and discussion
Synthesis and spectroscopy
Seven new organotin derivatives of I, RnSn(PhN2C2S3)4 Ϫ n [n =
1, R = Bu (1); n = 2, R = Ph (2), Bu (3), Me (4) and n = 3, Ph (5),
† Electronic supplementary information (ESI) available: discussion of
the spectral data. See http://www.rsc.org/suppdata/dt/b1/b109726a/
1036
J. Chem. Soc., Dalton Trans., 2002, 1036–1045
This journal is © The Royal Society of Chemistry 2002
DOI: 10.1039/b109726a

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Bu (6), Me (7)], have been synthesised by direct reaction of the
corresponding organotin chlorides and the potassium salt of I
(PhN2C2S3K) [eqn. (1)]. Further reaction of 7 with a large
RnSnCl4 Ϫ n ϩ (4 Ϫ n) PhN2C2S3K
RnSn(PhN2C2S3)4 Ϫ n ϩ (4 Ϫ n) KCl (1)
n = 1, R = Bu (1);
n = 2, R = Ph (2), Bu (3), Me (4);
n = 3, R = Ph (5), Bu (6), Me (7).
excess of 4,4Ј-bipy or 4-PyNH2 in diethyl ether results in the
formation of a dinuclear adduct, [Me3Sn(PhN2C2S3)]2ؒ(4,4Ј-
bipy) (8), and a fully ionic species, [Me3Sn(4-PyNH2)2]ϩ-
[PhN2C2S3]Ϫ (9), respectively [eqn. (2, 3)]. All derivatives 1–9 are
(2)
(3)
Fig. 1 The structure of compound 1, showing the labelling used in the
text. Thermal ellipsoids are at the 30% probability level (as in all
figures). Selected metric data: Sn(1)–C(1) 2.128(3), Sn(1)–S(1)
2.4687(7), Sn(1)–S(4) 2.4616(6), Sn(1)–S(7) 2.4523(7), S(1)–C(5)
1.740(2), S(2)–C(5) 1.733(2), S(2)–C(6) 1.749(3), S(3)–C(6) 1.655(3),
S(4)–C(13) 1.744(3), S(5)–C(13) 1.737(3), S(5)–C(14) 1.749(3), S(6)–
C(14) 1.653(3), S(7)–C(21) 1.739(3), S(8)–C(21) 1.740(3), S(8)–C(22)
1.734(3), S(9)–C(22) 1.654(3), N(1)–C(5) 1.295(3), N(3)–C(13) 1.292(3),
N(5)–C(21) 1.294(3) Å; C(1)–Sn(1)–S(1) 118.59(8), C(1)–Sn(1)–S(4)
117.41(8), C(1)–Sn(1)–S(7) 115.40(7), S(4)–Sn(1)–S(1) 95.83(2), S(7)–
Sn(1)–S(1) 105.75(2), S(7)–Sn(1)–S(4) 100.81(2)Њ.
air stable in the solid state. Compound 6 was obtained as pale
yellow oil which turned into a crystalline solid at low temper-
ature. Compounds 1–8 are soluble in common organic solvents
excepting hexane (1–5, 7, 8), while the insolubility of 9 can be
explained by its ionic character. Recrystallisation from thf–
hexane (1–4), diethyl ether–hexane (5, 7) or diethyl ether (8)
gave the products as pale yellow (1–4) or colourless (5–9)
crystalline solids. Synthesis of 9 yielded the product as a colour-
less crystalline solid of analytical purity directly, without
recourse to further purification.
Since the intramolecular Sn ؒ ؒ ؒ N interactions previously
described are significantly longer than the intermolecular
N
Sn secondary coordinations found for related compounds
such as organotin tetrazoles [2.27(1)–2.43(1) Å],21,22 the
coordination pattern of the PhN2C2S3 ligand can be described
as essentially S-monodentate, with a weak chelation through
the ring nitrogen, i.e. anisobidentate. The exocyclic C–S dis-
A discussion of the spectral data associated with 1–9 is
available as ESI.†
Structural chemistry
tances [C–S: 1.739(3)–1.744(3); C᎐S: 1.653(3)–1.655(3) Å] are
close to the corresponding values found for coordinated thiol
Suitable crystals for X-ray diffraction analysis were grown from
thf–hexane (1–3) or diethyl ether–hexane (7) at room temper-
ature, or from diethyl ether solution at low temperature (8). Due
to the insolubility of 9, crystals of satisfactory quality were
obtained by slow diffusion of diethyl ether solutions of the two
starting materials at room temperature over a period of one
week.
᎐
groups [1.70(1)–1.744(8) Å] and non-bonded thione groups
5
[1.67(1) Å] in C3N3S3(SnR3)3 and [(C3N3S3H){Co(en)2}2]-
[ClO4]3ؒ2H2O.23 Despite the weak chelation of two PhN2C2S3
ligands, the C᎐N distances of all heterocycles are equal within
᎐
experimental error [1.292(3)–1.295(3) Å] and are comparable
to analogous bonds found in related aromatic heterocycles
[cf. [(C N S H){Co(en) } ][ClO ] ؒ2H O, C᎐N: 1.33(2) Å].23
Compound 1. The molecular structure of 1 (Fig. 1) consists of
discrete monomers containing distorted tetrahedral CSnS3
centres. The tin atom is directly bonded to the thiol groups
(C–S) of I, the Sn–S distances [2.4523(7)–2.4687(7) Å] falling
in the Sn–S bond length range determined previously for
organotin trithiotriazines [2.435(3)–2.4708(8) Å].5 The C–Sn–C
bond angles [115.40(4)–118.59(8)Њ] are slightly larger, while the
S–Sn–S angles [95.83(2)–105.75(2)Њ] are somewhat smaller
when compared to the ideal value of 109.5Њ. This structural
feature can be explained by the very weak anisobidentate
chelation of two PhN2C2S3 ligands through the ring nitrogen
atoms [Sn(1) ؒ ؒ ؒ N(1): 2.773(2), Sn(1) ؒ ؒ ؒ N(3) 2.891(2) Å].
Such chelation was not observed for the third ligand, its ring
nitrogen being placed at a distance of 4.23 Å from the metal
centre. Within the four-membered SSnNC chelate rings, the
shortening of the Sn ؒ ؒ ؒ N distance leads to a marginal
increase in the C–Sn–S bond angle [C(1)–Sn(1)–S(1): 118.59(8);
C(1)–Sn(1)–S(4) 117.4(8)Њ] and a simultaneous decrease in the
C–S–Sn angle by ca. 2Њ [C(5)–S(1)–Sn(1): 90.49(8); C(13)–S(4)–
Sn(1) 92.68(8)Њ]. Moreover, the smallest S–Sn–S angle occurs
between the two Sn–S bonds involved in the chelate rings
[S(1)–Sn(1)–S(4): 95.83(2)Њ].
᎐
3
3
3
2
2
4 3
2
The heterocyclic units are essentially planar [maximum
deviation 0.016 Å] and the phenyl rings are twisted by ca. 50Њ
[N–N–C–C: Ϫ49.7(3) to 57.7(3)Њ] with respect to these planes.
As the structure of the PhN2C2S3 ligand in 2–3, 7 and 8 is
similar to that found in 1, it will be not discussed further.
Compound 2. The asymmetric unit of 2 was found to consist
of one half of the molecule, the remainder being generated by
a two-fold axis through the metal in the S–Sn–SЈ plane and
bisecting the C–Sn–CЈ angle (Fig. 2). The Sn–S bond [2.470(2)
Å] is typical and compares well with the analogous bonds in
1 [2.4523(7)–2.4687(7) Å] and related compounds [cf. (PhN4-
CS)2SnBu2, Sn–S: 2.477(4) Å].8 The coordination about tin is
essentially tetrahedral, with two weak intramolecular Sn ؒ ؒ ؒ N
interactions [Sn(1) ؒ ؒ ؒ N(1): 2.97 Å] distorting the coordin-
ation geometry towards an C2SnS2N2 bicapped tetrahedron.
This interaction is even weaker than those found for 1
[Sn ؒ ؒ ؒ N: 2.773(2)–2.891(2) Å] and the C–Sn–S bond angles
[109.8(2)–113.8(2)Њ] are closer to the ideal tetrahedral value.
However, the distortion of the C–Sn–CЈ [117.7(4)Њ] and S–Sn–
SЈ angles [88.35(9)Њ] reflects the weak anisobidentate chelation
J. Chem. Soc., Dalton Trans., 2002, 1036–1045
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average of 131.4(2)Њ approximating the C–Sn–C angle of
Bu2Sn(SCN4Ph)2 [130.7(4)Њ]. Moreover, the acute S–Sn–S
angles of 3 are comparable to the corresponding bond angles
found for 2 [88.35(9)Њ] and Bu2Sn(SCN4Ph)2 [86.6(2)Њ], falling
close to the octahedral value of 90Њ. Nevertheless, the S–Sn–C
angles of 3 lie in a narrow range [A: 107.26(8)–110.49(8); B:
104.55(8)–105.70(8)Њ] close to the tetrahedral value. These
findings are in good agreement with an increase in the coordin-
ation number at the tin atom due to the weak anisobidentate
chelation of the ligands through their ring nitrogen atoms.
The intramolecular Sn ؒ ؒ ؒ N interactions in 3 [A: 2.923(2); B:
2.911(2) Å] are comparable to those found for 2 [2.97 Å]
and Bu2Sn(SCN4Ph)2 (2.99 Å) and support the previous
interpretation.
Fig. 2 The structure of compound 2, showing the labelling used in the
text. Selected metric data: Sn(1)–C(3) 2.117(7), Sn(1)–S(1) 2.470(2),
S(1)–C(1) 1.748(8), S(2)–C(1) 1.727(7), S(2)–C(2) 1.751(8), S(3)–C(2)
1.666(7), N(1)–C(1) 1.278(10) Å; C(3)–Sn(1)–C(3Ј) 117.7(4), S(1)–
Sn(1)–S(1Ј) 88.35(9), C(3)–Sn(1)–S(1) 113.8(2), C(3)–Sn(1)–S(1Ј)
109.8(2)Њ.
Compound 7. The molecular structure of 7 (Fig. 4) contains a
trigonal bipyramidal trans-S2SnC3 centre, consistent with the
spectral data.† All S–Sn–S and C–Sn–C bond angles [172.95(2)
and 114.7(2)–119.3(1)Њ, respectively] support this description.
The tin atom is directly bonded to the thiol (C–S) group of I
and is further coordinated intermolecularly by the thione group
of the ligands, the latter value being comparable to the S–Sn–SЈ
value found for compounds displaying similar structural
features [cf. (PhN4CS)2SnBu2: 86.6(2); Me2Sn[S(O)CNC4H4]2:
92.6(1)Њ].8,24
(C᎐S) of a neighbouring molecule. The two Sn–S bonds are of
᎐
different lengths. Thus, the Sn(1)–S(1) distance [2.5409(9) Å],
although slightly longer than the corresponding bonds of 1–3
[Sn–S: 2.4523(7)–2.4894(8) Å], is comparable with the Sn–S
bond lengths found for organotin thiotetrazoles [2.477(4)–
2.614(5) Å].4,7 Furthermore, the intermolecular Sn(1)–S(3) dis-
tance [3.2274(8) Å], though long, falls in the range proposed for
secondary Sn ؒ ؒ ؒ S coordination [2.79–3.81 Å]6 and the ligand
can be described as unsymmetrical S(1),S(3)-bidentate bridg-
ing. Such coordination behaviour brings no major changes in
the structure of the PhN2C2S3 ligand, both C–S bond lengths
[S(1)–C(4): 1.730(3) and S(3)–C(5): 1.668(3) Å] lying close to
the corresponding distances found for 1–3 [C–S: 1.732(3)–
Compound 3. The overall crystal structure of 3 (Fig. 3)
contains two molecules (labelled as A and B) containing
slightly different tin centres, as suggested by the Mössbauer
spectroscopy.† The asymmetric unit of 3 was found to consist
of two halves of each of molecules A and B, the remainder
being generated by mirror planes bisecting the S–Sn–S planes
and containing the α- and γ-carbon atoms of one Bu, as well as
all the carbon atoms of the other Bu group. The molecular
structure of 3 is similar to those of 2 and Bu2Sn(SCN4Ph)2.7
Thus, the heterocyclic ligands are primarily monodentate
through their thiol (C–S) groups and the approximately equal
Sn–S distances [A: 2.4832(7); B: 2.4894(8) Å] fall close to the
corresponding bond lengths found for 2 [2.471(2) Å] and
Bu2Sn(SCN4Ph)2 [2.477(4) Å]. The coordination polyhedra
at the tin atoms can be described as distorted tetrahedra or,
alternatively, highly distorted octahedra. In accord with this
view are the large C–Sn–C angles [A: 126.1(2); B: 136.7(2)Њ] and
a concomitant decrease in the S–Sn–S angle [A: 88.86(4); B:
89.91(4)Њ]. When compared to related compounds, the C–Sn–C
angles of 3 were found to be larger than that of 2 [117.7(4)Њ], the
1.748(8) and C᎐S: 1.653(3)–1.668(7) Å].
᎐
Compound 8. The asymmetric unit of 8 (Fig. 5) was found to
consist of one half of the dinuclear molecule, the remainder
being generated by an inversion centre at the midpoint of the
4,4Ј-bipy ligand. The structure contains two Me3Sn(S3C2N2Ph)
units associated through a bridging 4,4Ј-bipy moiety. The
coordination environment around tin is trans-NSSnC3 with the
axial positions occupied by the thiol sulfur of the heterocycle
and the ring nitrogen of the neutral bipyridyl donor. The S–Sn–
Fig. 3 The structure of compound 3, showing the labelling used in the text. Selected metric data: Sn(1)–C(9) 2.128(4), Sn(1)–C(29) 2.133(5), Sn(1)–
S(1) 2.4832(7), S(1)–C(1) 1.737(3), S(2)–C(1) 1.731(3), S(2)–C(2) 1.751(3), S(3)–C(2) 1.661(3), N(1)–C(1) 1.298(4), Sn(2)–C(21) 2.138(4), Sn(2)–C(25)
2.116(5), Sn(2)–S(4) 2.4894(8), S(4)–C(13) 1.732(3), S(5)–C(13) 1.732(3), S(5)–C(14) 1.746(3), S(6)–C(14) 1.660(3), N(3)–C(13) 1.303(4) Å; C(9)–
Sn(1)–C(29) 126.10(16), S(1)–Sn(1)–S(1Ј) 88.86(4), C(9)–Sn(1)–S(1) 107.26(8), C(29)–Sn(1)–S(1) 110.49(8), C(25)–Sn(2)–C(21) 136.73(16),
S(4)–Sn(2)–S(4Ј) 89.91(4), C(21)–Sn(2)–S(4) 105.70(8), C(25)–Sn(2)–S(4) 104.55(8)Њ.
1038
J. Chem. Soc., Dalton Trans., 2002, 1036–1045

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acidity, hence the increased strength of the bonds to the
coordinated pyridine donors. Similar to 7 and 8, the axial and
equatorial bond angles in 9 are close to the ideal values
expected for a trigonal bipyramidal environment around tin.
The non-bonded anionic heterocyclic ligand is situated in the
vicinity of the –NH2 groups of both coordinated PyNH2-4
molecules, with N–H ؒ ؒ ؒ S hydrogen bonds between the amino
groups and the exocyclic S atoms being evident (see below). The
Ϫ
differences between the structure of the PhN2C2S3 anion in 9
and the related ligands in 1–3, 7 and 8 derive from the lengths
of C–S and C᎐S bonds. Thus, the shortening of the thiol bond
᎐
[C(1)–S(1): 1.705(2); cf. 1.725(2)–1.748(8) Å in 1–3, 7 and 8] is
probably due to the lack of any S–Sn interaction, while the
marginal lengthening of the thione bond [C(2)–S(3): 1.683(2)
vs. 1.653(3)–1.668(3) Å in 1–3, 7 and 8] probably reflects the
relative strength of the H-bond in 9 compared to weak bridging
in 7 and no –or much weaker– secondary interactions in 1–3
and 8.
Supramolecular structures
Fig. 4 The structure of compound 7, showing the labelling used in the
text. Selected metric data: Sn(1)–C(1) 2.132(3), Sn(1)–C(2) 2.130(3),
Sn(1)–C(3) 2.134(3), Sn(1)–S(1) 2.5409(9), Sn(1)–S(3) 3.2274(8), S(1)–
C(4) 1.730(3), S(2)–C(4) 1.748(3), S(2)–C(5) 1.739(3), S(3)–C(5)
1.668(3), N(1)–C(4) 1.296(4) Å; C(2)–Sn(1)–C(1) 119.28(14), C(2)–
Sn(1)–C(3) 118.73(16), C(1)–Sn(1)–C(3) 114.68(16), C(1)–Sn(1)–S(1)
104.92(10), C(2)–Sn(1)–S(1) 97.24(11), C(3)–Sn(1)–S(1) 95.01(10),
C(1)–Sn(1)–S(3) 77.56(8), C(2)–Sn(1)–S(3) 75.90(9), C(3)–Sn(1)–S(3)
89.82(9), S(1)–Sn(1)–S(3) 172.95(2)Њ.
The supramolecular structure of 1 is complex, as a large
number of intermolecular S ؒ ؒ ؒ S contacts are apparent.
Notably however, the thiol sulfurs S(1) and S(4), which
approach each other most closely intramolecularly [<S–Sn–S:
95.83(2)Њ], have no intermolecular contacts < 3.7Å. Conversely,
thiol S(7) and endocyclic S(2) are 3.59 Å from each other, while
the remaining endocyclic sulfurs partner thiones [S(5) ؒ ؒ ؒ S(9):
3.34, S(3) ؒ ؒ ؒ S(8): 3.49 Å], leaving thione S(6) largely
uninvolved [S(6) ؒ ؒ ؒ S(1): 3.78 Å].
The supramolecular structures of 3, 7, 8 and 9 are dominated
by molecular chains propagated through S Sn and/or S ؒ ؒ ؒ S
and/or N–H ؒ ؒ ؒ S intermolecular interactions. The molecules
of 3 aggregate in the solid state through weak intermolecular
S ؒ ؒ ؒ S interactions [S(2) ؒ ؒ ؒ S(6): 3.710(1); S(3) ؒ ؒ ؒ S(5):
3.817(1) Å] directed by the endocyclic and thione sulfur atoms
of each pair of neighbouring ligands (Fig. 7). The two S ؒ ؒ ؒ S
interactions describe a six-membered ring (S4C2) which deviates
significantly from planarity [torsion angle C(2)–S(3)–S(5)–
C(14): Ϫ53.8(1)Њ] in a characteristic ‘chair’ conformation.
Despite these S ؒ ؒ ؒ S distances being at the limit of a Van der
Waals interaction (3.8 Å, based on recent data derived from
Me2S),26 they clearly govern the self-assembly of the molecules
into monodimensional chains which run parallel to each other
along the a axis.
N [176.27(4)Њ] and C–Sn–C angles [118.5(1)–126.6(1)Њ] reflect
this coordination geometry. The Sn–S bond length [2.6174(7) Å]
is slightly longer when compared with that of 7 [2.5409(9) Å] and
is at the longer end of the range of Sn–S distances measured for
organotin thiotetrazoles [2.477(4)–2.614(5) Å].4,7 Furthermore,
the Sn–N bond [2.613(2) Å] is longer than those found in
organotin tetrazoles [2.27(1)–2.43(1) Å]21,22 or the cationic
polymer [Me3Sn(4,4Ј-bipy)]nnϩ [2.411(2), 2.420(2) Å].25,35
Compound 9. The molecular structure of 9 (Fig. 6) reveals the
presence of two non-associated ionic units, a [Me3Sn(PyNH2-
4)2]ϩ cation and a [PhN2C2S3]Ϫ anion. The cationic unit con-
tains a trans-trigonal bipyramidal tin centre, as found in 7 and
8, although in 9 this geometry is obtained by coordination of
the ring nitrogen atoms of two neutral PyNH2-4 donors, which
complete the coordination sphere about tin. The two Sn–N dis-
tances [2.358(2), 2.351(2) Å] are equal within experimental
error and are somewhat shorter than those found in the poly-
meric cation [Me3Sn(4,4Ј-bipy)]nnϩ [2.411(2), 2.420(2) Å].25 The
cationic nature of the tin in 9 clearly has enhanced Lewis
As with 1, the thiol sulfurs which show close approach
intramolecularly [<S–Sn–S 88.86(4), 89.91(4)Њ], are not involved
in intermolecular contacts. The same situation also pertains
in 2, though somewhat surprisingly the endocyclic and thione
Fig. 5 The structure of compound 8, showing the labelling used in the text. Selected metric data: Sn(1)–C(1) 2.126(3), Sn(1)–C(2) 2.128(2),
Sn(1)–C(3) 2.136(2), Sn(1)–S(1) 2.6174(7), S(1)–C(4) 1.725(2), S(2)–C(4) 1.753(2), S(2)–C(5) 1.747(3), S(3)–C(5) 1.661(3), N(1)–C(4) 1.298(3) Å;
C(1)–Sn(1)–C(2) 122.82(11), C(1)–Sn(1)–C(3) 118.54(11), C(2)–Sn(1)–C(3) 115.59(10), C(1)–Sn(1)–S(1) 95.31(8), C(2)–Sn(1)–S(1) 98.51(7),
C(3)–Sn(1)–S(1) 93.52(7), C(1)–Sn(1)–N(3) 88.04(6), C(2)–Sn(1)–N(3) 78.26(6), C(3)–Sn(1)–N(3) 86.29(6), S(1)–Sn(1)–N(3) 176.28(4)Њ.
J. Chem. Soc., Dalton Trans., 2002, 1036–1045
1039

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Fig. 6 The structure of compound 9, showing the labelling used in the text. Selected metric data: Sn(1)–C(1) 2.126(3), Sn(1)–C(2) 2.132(2), Sn(1)–
C(3) 2.127(2), Sn(1)–N(1) 2.358(2), Sn(1)–N(3) 2.351(2), S(1)–C(14) 1.705(2), S(2)–C(14) 1.765(2), S(2)–C(15) 1.733(2), S(3)–C(15) 1.683(2),
N(5)–C(14) 1.305(3) Å; C(1)–Sn(1)–C(3) 120.44(10), C(1)–Sn(1)–C(2) 119.09(10), C(2)–Sn(1)–C(3) 120.46(10), C(1)–Sn(1)–N(1) 94.08(8), C(2)–
Sn(1)–N(1) 86.21(8), C(3)–Sn(1)–N(1) 90.79(8), C(1)–Sn(1)–N(3) 93.06(8), C(2)–Sn(1)–N(3) 89.71(8), C(3)–Sn(1)–N(3) 86.20(8), N(1)–Sn(1)–N(3)
172.83(7)Њ.
sulfurs of 2 show no short contacts, which contrasts markedly
with 3.
The molecules of 8 also aggregate in the solid state through
intermolecular S ؒ ؒ ؒ S interactions, generating monodimen-
sional chains that run parallel to each other (Fig. 9). When
compared to the supramolecular structure of 3 and 7, only the
coordinated thiol sulfurs in 8 are involved in such contacts,
probably due to the large size and rigidity of the dinuclear
molecules. On the other hand, the S ؒ ؒ ؒ S distance in 8
[S(1) ؒ ؒ ؒ S(1Ј): 3.4561(7) Å] is significantly shorter than those
found for 3 [3.710(1)–3.817(1) Å] and 7 [3.675(1)–3.689(2) Å]
and compares favourably to similar S ؒ ؒ ؒ S interactions found
for molecular superconductors, such as donor–acceptor com-
pexes of bis(ethylenedithio)tetrathiafulvalene (3.3–3.6 Å).20 As
no further intermolecular interactions were identified in the
crystal structure of 8, the supramolecular structure can be
described as essentially 1-D.
The supramolecular structure of 9 consists of a three-
dimensional network in which [Me3Sn(PyNH2-4)2]ϩ cations and
[PhN2C2S3]Ϫ anions are self-assembled by N–H ؒ ؒ ؒ S hydrogen
bonding, generated by the NH2 groups of both 4-H2NPy
molecules coordinated to tin and the neighbouring thiol S(1)
and thione S(3) sulfurs of the anionic heterocycle (Fig. 10). It is
noteworthy that the involvement of the non-bonded anionic
ligand (at least as far as the metal is concerned) in the construc-
tion of the supramolecular structure is unprecedented when
compared to previously characterised fully ionic compounds
containing an [R3SnD2]ϩ cation (D = H2O, CH3CN, NH3 and
0.5 4,4Ј-bipy).25,27–29 The N(2)–H(2B) ؒ ؒ ؒ S(1) [N(2) ؒ ؒ ؒ S(1):
3.562, H(2B) ؒ ؒ ؒ S(1): 2.665 Å; N(2)–H(2B) ؒ ؒ ؒ S(1): 175.22Њ]
and N(4)–H(4B) ؒ ؒ ؒ S(3) linkages [N(4) ؒ ؒ ؒ S(3): 3.365,
H(4B) ؒ ؒ ؒ S(3): 2.521 Å; N(4)–H(4B) ؒ ؒ ؒ S(3): 159.54Њ] lead to
molecular chains, containing alternating [Me3Sn(PyNH2-4)2]ϩ
cations and [PhN2C2S3]Ϫ anions, which run parallel to each
other along the a axis. Furthermore, these chains inter-
connect through N(2)–H(2A) ؒ ؒ ؒ S(1) [N(2) ؒ ؒ ؒ S(1): 3.541,
H(2A) ؒ ؒ ؒ S(1): 2.693 Å; N(2)–H(2A) ؒ ؒ ؒ S(1): 161.31Њ] and
N(4)–H(4A) ؒ ؒ ؒ S(3) interactions [N(4) ؒ ؒ ؒ S(3): 3.392,
H(4A) ؒ ؒ ؒ S(3): 2.559 Å; N(2)–H(4A) ؒ ؒ ؒ S(3): 161.66Њ], result-
ing in an expanded 3-D network. There are very few examples
of designed supramolecular assemblages of sulfur-mediated
hydrogen bonds. Recent crystallographic studies of trithio-
The intermolecular C᎐S Sn coordination in 7 leads to
᎐
infinite polymer chains containing the metal centres and
heterocyclic groups in approximately the same plane [torsion
angle N(1)–C(4)–S(1)–Sn(1): Ϫ14.8(3); Sn(1)–S(3)–C(2)–S(2):
19.7(5)Њ]. Relative to each chain, a second chain runs parallel,
inverted with respect to the first and linked by weak S ؒ ؒ ؒ S
interactions [S(1) ؒ ؒ ؒ S(2Ј) 3.689(2) Å] directed by the endo-
cyclic and the thiol sulfur atoms [Fig. 8(a)], which are slightly
shorter than those found for 3. Similar to 3, the two S ؒ ؒ ؒ S
linkages take place between each pair of neighbouring ligands
and generate a six-membered ring (S4C2) which displays a less
acute ‘chair’ conformation [torsion angle C(4)–S(1)–S(2Ј)–
C(4Ј): Ϫ30.5(2)Њ]. These interactions connect the polymers
in ‘ribbon’-type double-chain arrays. Furthermore, the thiol
sulfurs S(1) of the neighbouring double-chain ribbons
interconnect at a distance of 3.675(1) Å and the Ph groups
which occupy the space between these ribbons π-stack in a
face-to-face manner [Ph ؒ ؒ ؒ Ph: 3.53–3.56 Å] [Fig. 8(b)]. This
structural feature leads to an expansion of the supramolecular
structure of 7 to a three-dimensional network.
Fig. 7 The supramolecular structure of 3, showing weak intermolec-
ular S ؒ ؒ ؒ S interactions
1040
J. Chem. Soc., Dalton Trans., 2002, 1036–1045

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this study relate to the roles of intermolecular coordination,
hydrogen bonding and S ؒ ؒ ؒ S interactions in controlling
supramolecular assemblies. Although this work relates specif-
ically to organotin chemistry, some potentially more general
inferences can be drawn.
Firstly, only the thione sulfur involves itself in intermolecular
coordination to tin. Bridging sulfur ligands are rare in organotin
chemistry, particularly in comparison with the plethora of
N- and O-bridged structures. In cases where N-donors are
available (8, 9), these preferentially coordinate the metal at the
expense of C᎐S Sn. That such an interaction is observed in
᎐
the trimethyltin compound 7, but not in any of the di- and
mono-organotin analogues 1–3, probably reflects the preference
of the softer triorganotin monocation for sulfur, the [R4 Ϫ nSn]nϩ
(n = 2, 3) receptors opting for weak internal chelation by harder
N-donors. Interestingly, the structure of Me3Sn[SP(Ph)2NP-
(Ph)2S], which we have previously determined, is the only other
structurally authenticated 1-D, S-bridged organotin polymer32
and provides the only instance of a dithioimidodiphosphinate
ligand behaving this way.
Where metal coordination does not occur, the thione group
chooses a hydrogen-bonding role rather than involvement in
S ؒ ؒ ؒ S interactions (9), and only when neither of the first two
options are available do the latter occur (1–3, 8). Additionally,
hydrogen bonds are also formed by the thiol sulfur in preference
to S ؒ ؒ ؒ S interactions (9), but are slightly weaker than those
involving the thione group (9: 3.37, 3.39 vs 3.54, 3.56 Å).
The pattern of S ؒ ؒ ؒ S interactions in the compounds studied
in this work is complex, but a general trend appears to be
emerging which largely rationalises the sequence in which thiol,
thione and endocyclic sulfur centres involve themselves in
such an array. Homoleptic thiol–thiol interactions seem to
be the most significant, since in 8 (where S Sn and
H-bonding are absent), all the sulfurs are available, yet only
(thiol)S ؒ ؒ ؒ S(thiol) contacts are observed, and these are
relatively short (3.46 Å). In 1–3, we believe that the absence of
significant intermolecular (thiol)S ؒ ؒ ؒ S(thiol) contacts arises
because analogous intramolecular interactions are already
present. Three pieces of evidence support this claim: firstly,
acute S–Sn–S angles are observed, which are not required by
the overall molecular geometry and/or coordination number at
tin; secondly, we have noted similar angular deformations in
(RS)4Sn and which subsequently lead to thermal elimination of
RSSR in CVD experiments;1 finally, in 1, the only notable
intermolecular contact involving a thiol sulfur occurs with
that thiol not involved in the close intramolecular S ؒ ؒ ؒ S
interaction [S(2)–S(7) 3.59 Å].
Homoleptic S ؒ ؒ ؒ S contacts between pairs of either thione
or endocyclic sulfurs do not occur, but both thiol–endocyclic
and thione–endocyclic pairings are observed. The available data
do not yet allow discrimination between the strengths of these
contacts. For example, comparison of 3 and 7 suggests that
(thione)S ؒ ؒ ؒ S(endo) contacts are marginally weaker (3: > 3.7
Å) than (thiol)S ؒ ؒ ؒ S(endo) interactions (7: ca. 3.7 Å), but in 1,
the (thione)S ؒ ؒ ؒ S(endo) interactions are notably stronger
(3.34, 3.49 Å) and are shorter than the one (thiol)S ؒ ؒ ؒ S(endo)
contact (1: 3.59 Å).
Fig. 8 The supramolecular structure of 7, showing (a) polymer
propagation via S Sn coordination and interchain S ؒ ؒ ؒ S contacts
and (b) additional inter-ribbon S ؒ ؒ ؒ S contacts and π-stacking of
aromatic groups.
We have made some attempt to rationalise these findings
with the aid of density functional theory to model the charge
distribution in the PhN2C2S3 ligand (L) and related species
(Table 1), though, clearly, any approach which deals with
isolated molecules cannot fully account for species in which
intermolecular interactions are widespread.
cyanuric acid and its adducts with Me2CO, melamine and
4,4Ј-bipy revealed layer- and chanel-type supramolecular
architectures built up via intermolecular N–H ؒ ؒ ؒ S inter-
actions [H ؒ ؒ ؒ S: 2.32–2.56 Å].30,31 Although the hydrogen
bonds in 9 are weaker than those previously described, they
govern the assembly of the molecules in the three dimensional
architecture. Moreover, the formation of hydrogen bonds
involving sulfur atoms is at the expense of weaker S ؒ ؒ ؒ S inter-
actions, which are absent in this structure.
In each of the modelled species, LϪ, LH and LSnMe3, the
lowest energy arrangement has the exocyclic phenyl group
twisted with respect to the heterocycle, by angles of 29.7, 44.4
and 50.8Њ, respectively, though the potential energy surface for
twist angles of 0–90Њ is rather flat. These values compare well
with twist angles of 47.9–66.3Њ observed across the six structure
determinations in this paper. The key internuclear distances in
Conclusions
The most significant conclusions that can be drawn from
J. Chem. Soc., Dalton Trans., 2002, 1036–1045
1041

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Fig. 9 The supramolecular structure of 8, showing intermolecular S ؒ ؒ ؒ S interactions
Table 1 Calculated bond lengths and atomic charges for L and related species
Bond lengths/Å
S1–C1 S2–C1
Atomic charges
S2–C3
S3–C3
N1–C1
S1
S2
S3
LϪ
9
LH
LSnMe3
1.698
1.705
1.765
1.754
1.725
1.812
1.765
1.755
1.762
1.753
1.755
1.733
1.787
1.781
1.744
1.689
1.683
1.653
1.656
1.661
1.316
1.305
1.291
1.297
1.298
Ϫ0.36
ϩ0.38
Ϫ0.28
ϩ0.09
Ϫ0.21
ϩ0.45
ϩ0.46
Ϫ0.10
Ϫ0.12
8
sulfur is predicted to be positive in both cases. This rationalises
the pairing of the endocyclic sulfur with either of the exocyclic
centres in intermolecular S ؒ ؒ ؒ S formation, i.e. it is charge
controlled. It also explains why only the (negative) exocyclic
sulfurs engage in the hydrogen bonding observed in 9.
What is less easy to accommodate is the formation of S ؒ ؒ ؒ S
interactions solely involving S1. Homoatomic S ؒ ؒ ؒ S inter-
actions will always bring together two atoms of identical
charge, so it is perhaps not surprising that S2 (repulsion of ϩ/ϩ)
and S3 (repulsion of Ϫ/Ϫ) do not form close homoatomic con-
tacts. On the other hand, S1 ؒ ؒ ؒ S1 contacts are observed in
both 7 and 8, and we can only speculate that this is perhaps due
to the polarisability of this sulfur. In our models, in contrast to
S2 and S3, which maintain a common net charge in LϪ, LH and
LSnMe3, the net charge on S1 varies from Ϫ0.36 to ϩ0.09 to
Ϫ0.21 across the same series (Table 1). However, there seems
no obvious reason from these data why the formation of
polarisation-induced homoatomic S1 ؒ ؒ ؒ S1 interactions should
occur in preference to charge-matched S1–S2 or S3–S2 inter-
actions, as seen in 8.
Fig. 10 The supramolecular structure of 9, showing self-assembly
through N–H ؒ ؒ ؒ S hydrogen bonds.
the anion are modelled rather well, though the S2–C1 and S2–C3
separations within the heterocycle are calculated to be slightly
longer than found in 9. A similar comment can be made about
the analogous distances calculated for an isolated molecule of
LSnMe3 (tetrahedral tin), where the S2–C1 and S2–C3 bonds are
predicted to be longer than found in 8. In addition, for both LH
and LSnMe3, the two S–C bonds within the heterocycle are
predicted to be reversed in order of bond length compared to
the anion LϪ, which is not clearly observed in the structures of
1–3, 7 and 8. However, in all of these latter structures the two
endocyclic S–C bonds are equal within experimental error and
in 1 (two out of three heterocycles), 2 and 3 the predicted order-
ing (before considering esds) is observed.
Experimental
Spectra were recorded on the following instruments: JEOL
GX270, Bruker AC270, JEOL GX400, Bruker AC400 (1H, 13
C
and 119Sn NMR), Perkin-Elmer 599B (IR). The NMR spectra
were recorded in saturated CDCl3 (1–8) or (CD3)2SO (I, 9)
solutions at room temperature. For all compounds, IR spectra
In the models of LϪ and LSnMe3, the exocyclic sulfurs are
predicted to both bear negative charges, while the endocyclic
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J. Chem. Soc., Dalton Trans., 2002, 1036–1045

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3
were recorded in Nujol mulls. Details of the Mössbauer
spectrometer and related procedures are given elsewhere.33
Isomer shift data are relative to CaSnO3 at 78 K. All other
chemicals were obtained commercially (e.g. Aldrich) and used
without further purification. All preparations were conducted
under an inert atmosphere using dried solvents.
(t, 6H, Sn(CH2)3CH3; J 7.2 Hz]. 13C NMR: δ 187.2 (C–S),
158.8 (C᎐S), 138.1 (1-Ph), 129.6 (3-Ph), 129.4 (4-Ph), 126.1
᎐
(2-Ph), 28.3 (SnCH2CH2CH2CH3), 26.7 [SnCH2(CH2)2CH3],
26.3 [Sn(CH2)2CH2CH3], 13.9 [Sn(CH2)3CH3], J[13C–117,119Sn]
1
447.0/468.1, 2J[13C–117,119Sn] 32.39 Hz (unresolved). 119Sn NMR:
δ 58.9. Mössbauer (mm sϪ1): i.s. 1.12, 1.42; q.s. 2.26, 2.85. IR
(cmϪ1): 1588, 1344, 1251, 1059, 1020, 826, 761, 707, 690.
Syntheses
Bis(5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)-
5-Mercapto-3-phenyl-1,3,4-thiadiazoline-2-thione potassium
salt, monohydrate (I). The synthesis of PhN2C2S3KؒH2O is a
modification of the literature method.34 PhNHNH2 (5.4 g, 50
mmol) was dissolved in a mixture of N,N-dimethylformamide
(50 ml) and pyridine (10 ml), and CS2 (10 ml) was added drop-
wise. The reaction was warmed slowly to 100 ЊC over a period
of 1–2 h and stirred at this temperature for 30 min, until H2S
evolution was complete. After removing the solvent in vacuo,
the resulting waxy solid was re-dissolved in a mixture of water
(100 ml) and aqueous 5% Na2CO3 solution (10 ml); the small
amount of solid remaining was extracted in diethyl ether. The
aqueous solution was separated, treated with concentrated HCl
(7 ml) and the resulting precipitate filtered off and dried at
room temperature to give the acid, PhN2C2S3H, as a white
powder (9.5 g, 84%).
dimethyltin (4). Yield 76%, mp 142 ЊC. Found (calc. for
1
C18H16N4S6Sn): C, 35.9 (36.1); H, 2.7 (2.7); N 9.3 (9.4)%. H
NMR: δ 7.62 (d, 4H, 2-Ph; 3J 7.8 Hz), 7.46 (m, 6H, 3,4-Ph), 1.11
(s, 6H, SnCH3), 2J[1H–117,119Sn] 66.4 Hz (unresolved). 13C
NMR: δ 187.0 (C–S), 157.8 (C᎐S), 138.0 (1-Ph), 129.4 (3-Ph),
᎐
129.35 (4-Ph), 125.8 (2-Ph), 5.6 (SnCH3), 1J[13C–117,119Sn] 448.4/
428.3 Hz. 119Sn NMR: δ 71.3. Mössbauer (mm sϪ1): i.s. 1.41; q.s.
2.67. IR (cmϪ1): 1583, 1350, 1249, 1069, 1055, 828, 783, 759,
706, 684, 668.
(5-Mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)triphen-
yltin (5). Yield 75%, mp 128 ЊC, Found (calc. for C26H20N2-
1
S3Sn): C, 54.3 (54.3); H, 3.5 (3.5); N 4.9 (4.9)%. H NMR:
δ 7.64 (d, 6H, 2-PhSn; 3J 6.6 Hz), 7.45–7.24 (m, 14H, 3,4-PhSn,
2,3,4-Ph). 13C NMR: δ 186.7 (C–S), 155.8 (C᎐S), 137.7 (1-Ph),
᎐
136.6 (1-PhSn), 136.3 (3-PhSn), 130.0 (3-Ph), 128.9 (4-Ph),
128.6 (4-PhSn), 128.4 (2-PhSn), 125.4 (2-Ph). 119Sn NMR:
δ Ϫ62.4. Mössbauer (mm sϪ1): i.s. 1.34; q.s. 2.85. IR (cmϪ1):
1590, 1356, 1237, 1073, 1031, 834, 762, 693, 682.
PhN2C2S3H (9.5 g, 42 mmol) was re-dissolved in hot EtOH
(100 ml). The addition of an EtOH solution (100 ml) of KOH
(2.4 g, 42 mmol) induced precipitation of the product as a
microcrystalline white solid (10.5 g, 89%), mp 236 ЊC. Found
(calc. for C8H7N2OS3K): C, 33.7 (34.0); H, 2.5 (2.5); N 9.9
1
3
(5-Mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)tributyl-
tin (6). Pale yellow oil at room temperature, yield 72%, Found
(calc. for C20H32N2S3Sn): C, 46.3 (46.4); H, 6.2 (6.3); N 5.4
(9.8)%. H NMR: δ 7.67 (d, 2H, 2-Ph, J 7.5), 7.46 (dd, 2H,
3-Ph, 3J 7.2/8.1), 7.36 (dd, 1H, 4-Ph, 3J 7.2/7.5 Hz), 3.59 (s, 2H,
H2O). 13C NMR: δ 185.0 (C–S), 173.7 (C᎐S), 139.6 (1-Ph),
᎐
1
3
128.9 (3-Ph), 128.3 (4-Ph), 126.1 (2-Ph). IR (cmϪ1): 3364, 1596,
1590, 1352, 1239, 1071, 1046, 830, 758, 696, 683.
(5.4)%. H NMR: δ 7.68 (d, 2H, 2-Ph; J 8.1), 7.44 (m, 3H,
3,4-Ph), 1.54 [m, 6H, SnCH2CH2CH2CH3], 1.29 (m, 12H,
3
SnCH2CH2CH2CH3), 0.85 (dd, 9H, Sn(CH2)3CH3; J 7.1/7.5
Hz]. 13C NMR: δ 187.2 (C–S), 158.2 (C᎐S), 138.4 (1-Ph), 128.7
᎐
Tris(5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)-
butyltin (1). I (0.96 g, 3.4 mmol) was suspended in a thf (50 ml)
solution of BuSnCl3 (0.28 g, 1.0 mmol) and the mixture was
stirred overnight at room temperature. After removing the solid
residue and concentrating the filtrate to low volume, the
addition of hexane (50 ml) induced crystallisation of the
product as a microcrystalline yellow solid (0.65 g, 77%), mp
128 ЊC dec. Found (calc. for C28H24N6S9Sn): C, 39.4 (39.5); H,
(3,4-Ph), 125.5 (2-Ph), 28.3 (SnCH2CH2CH2CH3), 26.8
[Sn(CH2)2CH2CH3], 16.1 [SnCH2(CH2)2CH3], 13.4 [Sn(CH2)3-
CH3], 1J[13C–117,119Sn] 310.7/325.0, 2J[13C–117,119Sn] 23.1
(unresolved), 3J[13C–117,119Sn] 65.0 (unresolved). 119Sn NMR:
δ 120.5. Mössbauer (mm sϪ1): i.s. 1.41; q.s. 2.75. IR (cmϪ1):
1592, 1336, 1237, 1072, 1045, 822, 758, 701, 687, 668.
(5-Mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)trimeth-
1
3
2.9 (2.8); N 9.6 (9.9)%. H NMR: δ 7.53 (d, 6H, 2-Ph; J 7.0),
7.43 (m, 9H, 3,4-Ph), 2.07 [m, 2H, SnCH2(CH2)2CH3], 1.27 (m,
2H, SnCH2CH2CH2CH3), 0.89 [m, 2H, Sn(CH2)2CH2CH3],
0.46 [t, 3H, Sn(CH2)3CH3; 3J 7.0 Hz]. 13C NMR: δ 186.6 (C–S),
yltin (7). Yield 81%, mp 96 ЊC. Found (calc. for C11H14N2S3Sn):
1
C, 34.0 (34.0); H, 3.6 (3.6); N 7.1 (7.2)%. H NMR: δ 7.70 (d,
3
3
2H, 2-Ph; J 7.8), 7.47 (t, 2H, 3-Ph; J 7.8 Hz ), 7.40 (m, 1H,
4-Ph), 0.63 (s, 9H, SnCH3), 2J[1H–117,119Sn] 56.2 Hz
155.1 (C᎐S), 137.3 (1-Ph), 129.3 (3-Ph), 129.0 (4-Ph), 125.5
(unresolved). 13C NMR: δ 186.9 (C–S), 157.8 (C᎐S), 138.3
᎐
᎐
(2-Ph), 36.4 (SnCH2CH2CH2CH3), 27.5 [SnCH2(CH2)2CH3],
25.3 [Sn(CH2)2CH2CH3], 13.1 [Sn(CH2)3CH3]. 119Sn NMR:
δ Ϫ10.2. Mössbauer (mm sϪ1): i.s. 1.52; q.s. 1.93. IR (cmϪ1):
1590, 1340, 1233, 1061, 827, 765, 710, 692, 681.
(1-Ph), 128.7 (3-Ph), 128.6 (4-Ph), 125.3 (2-Ph), Ϫ2.79
1
(SnCH3), J[13C–117,119Sn] 347.0/363.6 Hz. 119Sn NMR: δ 126.1.
Mössbauer (mm sϪ1): i.s. 1.36; q.s. 2.89. IR (cmϪ1): 1600, 1350,
1242, 1153, 1077, 1042, 830, 773, 760, 681, 667.
The complexes 2–7 were also prepared by the same method:
Bis-[(5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)-
trimethyltin]ؒ4,4Ј-bipyridine (8). A large excess of 4,4Ј-bipy
(0.31 g, 2.0 mmol) was added to a solution of 7 (0.39 g,
1.0 mmol) in diethyl ether (60 ml). After stirring for 3 h at
room temperature, the colourless solution was concentrated
and stored at low temperature to yield the product as a colour-
less crystalline solid (0.37 g, 79%), mp 104 ЊC. Found (calc. for
Bis(5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)-
diphenyltin (2). Yield 62%, mp 212 ЊC. Found (calc. for
1
C28H20N4S6Sn): C, 46.4 (46.5); H, 2.8. (2.8); N, 7.8 (7.7)%. H
3
3
NMR: δ 7.76 (d, 4H, 2-PhSn; J 6.6), 7.55 (d, 4H, 2-Ph; J 8.2
Hz), 7.52–7.36 (m, 12H, 3,4-Ph, 3,4-PhSn)]. 13C NMR: δ 185.4
(C–S), 138.6 (1-Ph), 135.8 (1-PhSn), 134.5 (3-PhSn), 128.5
(3-Ph), 128.3 (4-Ph), 128.25 (4-PhSn), 125.7 (2-Ph). 119Sn
NMR: δ Ϫ84.4. Mössbauer (mm sϪ1): i.s. 1.36; q.s. 2.49. IR
(cmϪ1): 1587, 1342, 1244, 1056, 1019, 816, 766, 711, 687, 682.
1
C32H36N6S6Sn2): C, 40.8 (41.1); H, 3.9 (3.9); N 9.0 (9.0)%. H
NMR: δ 8.63 (d, 4H, 2-bipy; 3J 6.2), 7.69 (d, 4H, 2-Ph; 3J 8.1),
7.53 (d, 4H, 3-bipy; 3J 6.2), 7.42 (dd, 4H, 3-Ph; 3J 7.3/8.1), 7.34
3
2
(t, 2H, 4-Ph; J 7.3 Hz), 0.65 (s, 18H, SnCH3), J[1H–117,119Sn]
Bis(5-mercapto-3-phenyl-1,3,4-thiadiazoline-2-thionato)-
57.5/59.7 Hz. 13C NMR: δ 186.5 (C–S), 158.6 (C᎐S), 149.7
᎐
dibutyltin (3). Yield 73%, mp 118 ЊC. Found (calc. for
(2-bipy), 145.2 (4-bipy), 138.1 (1-Ph), 128.4 (3-Ph), 128.3
1
1
C24H28N4S6Sn): C, 42.1 (42.2); H, 4.1 (4.1); N 8.0 (8.2)%. H
(4-Ph), 125.1 (2-Ph), 121.3 (3-bipy), Ϫ1.86 (SnCH3), J[13C–
3
NMR: δ 7.57 (d, 4H, 2-Ph; J 7.8), 7.46 (m, 6H, 3,4-Ph), 1.75
117,119Sn] 364.7 Hz (unresolved). 119Sn NMR: δ 77.6. Mössbauer
(mm sϪ1): i.s. 1.34; q.s. 3.15. IR (cmϪ1): 1595, 1337, 1233, 1071,
1027, 825, 803, 778, 761, 694, 682.
[m, 4H, SnCH2(CH2)2CH3], 1.46 (quint, 4H, SnCH2CH2-
CH2CH3; 3J 7.8), 1.18 [sext, 4H, Sn(CH2)2CH2CH3; 3J 7.2], 0.69
J. Chem. Soc., Dalton Trans., 2002, 1036–1045
1043

View Article Online
Table 2 Crystal data and structure refinement details for compounds 1–3 and 7–9
Compound
1
2
3
7
8
9
Empirical formula
Formula weight
C28H24N6S9Sn
851.76
C28H20N4S6Sn
723.53
C24H28N4S6Sn
683.55
C11H14N2S3Sn
389.11
C16H18N3S3Sn
467.20
C21H26N6S3Sn
577.35
T /K
Crystal system
Space group
170(2)
Monoclinic
P21/n
170(2)
Monoclinic
C2/c
170(2)
Monoclinic
P21/m
170(2)
170(2)
170(2)
Monoclinic
P21/n
Triclinic
Triclinic
¯
¯
P1
P1
a/Å
b/Å
c/Å
α/Њ
15.5450(2)
8.61900(10)
26.9590(5)
11.924(1)
21.975(2)
11.255(1)
7.1380(2)
22.9540(6)
17.7060(4)
6.5200(3)
7.5280(3)
15.3790(5)
94.574(3)
95.404(3)
94.757(3)
745.97(5)
2
9.5700(3)
9.6900(3)
12.5000(4)
105.222(2)
96.477(2)
119.362(2)
933.74(5)
2
14.7340(3)
10.6880(2)
15.9380(3)
β/Њ
104.378(1)
96.340(12)
94.890(1)
95.9610(11)
γ/Њ
U/Å3
3498.90(9)
4
1.298
2931.1(4)
4
1.326
2891.5(1)
4
1.339
2496.30(8)
4
1.295
Z
µ/mmϪ1
2.113
1.705
Independent
reflections
Goodness-of-fit on F 2
R1, wR2 [I > 2σ(I )]
R1, wR2 (all data)
8001 [R(int) =
2582 [R(int) =
8603 [R(int) =
3393 [R(int) =
4265 [R(int) =
5723 [R(int) =
0.0602]
0.0122]
0.0496]
0.0418]
0.0384]
0.0392]
1.042
0.0349, 0.0656
0.0553, 0.0710
1.108
0.0523, 0.1682
0.0533, 0.1687
0.802
0.0404, 0.1188
0.0707, 0.1446
1.028
0.0348, 0.1157
0.0380, 0.1196
1.005
0.0302, 0.0550
0.0407, 0.0589
0.574
0.0241, 0.0679
0.0320, 0.0790
[Di(4-aminopyridine)trimethyltin]؉[5-mercapto-3-phenyl-
1,3,4-thiadiazoline-2-thionato]؊ (9). A large excess of 4-H2NPy
(0.28 g, 3.0 mmol) in diethyl ether (50 ml) was added dropwise
to a solution of 7 (0.39 g, 1.0 mmol) in diethyl ether (20 ml). A
pale yellow precipitate formed immediately. After stirring for
3 h at room temperature, the solvent was removed and the
precipitate was washed with diethyl ether and dried at room
temperature, yielding the product as a pale yellow microcrystal-
line solid (0.51 g, 88%). Alternatively, diethyl ether solutions of
the starting materials were allowed to diffuse slowly over 3 days.
Slow evaporation of the resultant solution gave the product
as a colourless crystalline solid (0.54 g, 93%), mp 136 ЊC.
Found (calc. for C21H26N6S3Sn): C, 43.8 (43.7); H, 4.6 (4.5);
N 14.6 (14.6)%. 1H NMR: δ 7.90 (d, 4H, 2-C5H4N; 3J 5.1), 7.70
positions. The β- and δ-carbons in both cases are disordered
in a 1 : 1 ratio on either side of the respective mirror planes
straddled by these groups [C(25)–C(28), C(29)–C(32)].
Full matrix anisotropic refinement was implemented in the
final least-squares cycles throughout. All data were corrected
for Lorentz and polarisation and, with the exception of 3, for
extinction. An absorption correction (multiscan) was applied to
data for 1, 3 7 and 9. Hydrogens were included at calculated
positions throughout.
CCDC reference numbers 168022–168027.
See http://www.rsc.org/suppdata/dt/b1/b109726a/ for crystal-
lographic data in CIF or other electronic format.
Density functional theory calculations
3
3
(d, 2H, 2-Ph; J 7.3), 7.42 (dd, 2H, 3-Ph; J 7.0/7.7), 7.33 (m,
1H, 4-Ph), 6.75 (s, 4H, NH2), 6.62 (d, 4H, 3-C5H4N; 3J 5.5 Hz),
0.57 (s, 9H, SnCH3), 2J[1H–117,119Sn] 66.3 Hz (unresolved).
All calculations were performed using the Gaussian 98
program,35 employing the B3LYP36–38 functional in conjunction
with the 6-31G* basis set for H, C, N and S,39 and the SDD
energy consistent pseudopotential basis set for Sn.40 All
geometries were fully optimised at the above level using the
default optimisation criteria of the program.
Molecular and electronic structure determinations for the
systems LϪ, LH and LSnMe3 (L = PhN2C2S3) were performed
under fully relaxed C1 symmetry. Further calculation of all
possible isomers for each system under rigid Cs symmetry
revealed the potential energy surfaces to be relatively flat with
respect to rotation about the N–Cipso and S–H or S–SnMe3
bonds, but with the Cs solutions being only slightly higher in
energy (≤ 11 kJ molϪ1) than the optimised C1 solution in each
case. Atomic charges for the C1 (and Cs) systems were predicted
using the natural population analysis (NPA) method imple-
mented within the Gaussian 98 program.41,42 Atomic charges
predicted for the individual Cs isomers were quantitatively very
similar to those for the fully relaxed C1 systems.
13C NMR: δ 185.3 (C–S), 172.7 (4-C H N), 156.5 (C᎐S), 147.1
᎐
5
4
(2-C5H4N), 139.7 (1-Ph), 128.9 (3-Ph), 128.3 (4-Ph), 126.1
1
(2-Ph), 109.7 (3-C5H4N), 0.00 (SnCH3), J[13C–117,119Sn] 509.0
Hz (unresolved). 119Sn NMR: δ Ϫ47.1. Mössbauer (mm sϪ1): i.s.
1.23; q.s. 3.08. IR (cmϪ1): 3350, 1635, 1613, 1559, 1518, 1350,
1288, 1234, 1068, 1031, 1007, 837, 829, 772, 760, 697, 664.
Crystallography
Experimental and crystallographic details relating to the struc-
ture determination of compounds 1–3 and 7–9 are given in
Table 2. Data for 2 were collected on a CAD4 automatic 4-circle
diffractometer, while all the other structures were determined
on a Nonius KappaCCD diffractometer.
It became evident in the early stages of refinement of 1 that
one of the phenyl rings [C(23)–C(28)] exhibited three-fold
positional disorder in the ring plane, which was successfully
modelled.
The asymmetric unit in 2 consisted of one half of a molecule,
the remaining portion being generated by a 2-fold rotation axis
implicit in the space group symmetry. Moreover, in this com-
pound, five of the carbon atoms in one of the phenyl rings
[C(9)–C(14)] exhibit disorder in a 1 : 1 ratio with carbons
C(902)–C(906) (not shown in Fig. 2). In the final least-squares
refinement, restraints were applied to the ADPs of four of these
disordered carbons.
In 3, the asymmetric unit consisted of two independent half-
molecules, each seated on a mirror plane. Consequently, two
butyl groups on each tin exhibit half site occupancy. In each
case, the carbons in one butyl group are seated entirely on the
relevant mirror plane, while the additional butyl groups exhibit
disorder whereby only the α- and γ-carbons are sited on special
Acknowledgements
We thank NATO for support in the form of a travel grant
(K. C. M., I. H) and NATO and The Royal Society for a
Postdoctoral Fellowship (M. M. V.)
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