Structural characterization of rare intramolecularly (1,4-Te?N) bonded diorganotellurides and their monomeric complexes with mercury(II) halides: Metal assisted C-H?X (Hg) interactions leading to supramolecular architecture

Article abstract of DOI:10.1016/j.jorganchem.2006.01.034

Monomeric tellurides 4-RC₆H₄(SB)Te [SB = 2-(4,4′-NO₂C₆H₄CHNC₆H ₃-Me); R = H, 1a; Me, 1b; OMe, 1c], which incidentally represent the first example of a telluride with 1,4-Te?N int

Full text of DOI:10.1016/j.jorganchem.2006.01.034

Journal of Organometallic Chemistry 691 (2006) 1954–1964
www.elsevier.com/locate/jorganchem
Structural characterization of rare intramolecularly
(1,4-Teꢀ ꢀ ꢀN) bonded diorganotellurides and their monomeric
complexes with mercury(II) halides: Metal assisted C–Hꢀ ꢀ ꢀX
(Hg) interactions leading to supramolecular architecture
a,
a
a
a
Ashok K.S. Chauhan *, Anamika , Arun Kumar , Puspendra Singh ,
a
b
c
d
Ramesh C. Srivastava , Ray J. Butcher , Jens Beckmann , Andrew Duthie
a
Department of Chemistry, University of Lucknow, Lucknow 226 007, India
Department of Chemistry, Howard University, Washington, DC 20059, USA
b
c
Institut fu¨r Chemie, Freie Universita¨t Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany
Centre for Chiral and Molecular Technologies, Deakin University, Geelong 3217, Australia
d
Received 22 October 2005; received in revised form 15 December 2005; accepted 3 January 2006
Available online 3 March 2006
Abstract
Monomeric tellurides 4-RC6H4(SB)Te [SB = 2-(4,40-NO2C6H4CH@NC6H3–Me); R = H, 1a; Me, 1b; OMe, 1c], which incidentally rep-
resent the first example of a telluride with 1,4-Teꢀ ꢀ ꢀN intramolecular interaction, have been prepared and characterized by solution and
solid-state 125Te NMR, 13C NMR and X-ray crystallography. Interplay of weak C–Hꢀ ꢀ ꢀO and C–Hꢀ ꢀ ꢀp interactions in the crystal lattice
of 1b and 1c are responsible for the formation of supramolecular motifs. These tellurides undergo expected oxidative addition reactions with
halogens and interhalogens and also interact coordinatively with mercury(II) halides to give 1:2 complexes, HgX2[4-RC6H4(SB)Te]2
(X = Cl, R = H, 2a; Me, 2b; OMe, 2c and X = Br, R = H, 3a; Me, 3b; and OMe, 3c) with no sign of Te–C bond cleavage, as has been
reported for some 1,5-Teꢀ ꢀ ꢀN(O) intramolecularly bonded tellurides. The complexes 2a and 3c are the first structurally characterized mono-
meric 1:2 adducts of mercury(II) halides with Te ligands. The 1,4-Teꢀ ꢀ ꢀN intramolecular interactions in the solid-state are retained in the
complexes highlighting simultaneously the Lewis acid and base character of the Te(II) atom. Packing of molecules in the crystal lattice of 2a
and 3c reveals that non-covalent C–Hꢀ ꢀ ꢀCl/Br interactions involving metal-bound halogen atoms possess significant directionality and in
combination with coordinative covalent interactions may be of potential use in creating inorganic supramolecular synthons.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Intramolecular bonding; Non-covalent interactions; Mercury halide complex; Tellurium ligands; Crystal engineering; C–Hꢀ ꢀ ꢀX interaction
1. Introduction
ence the mode of reaction of the tellurides (R2Te) with d8
and d10 metal acceptors. At least four different products
have been isolated in the reactions with mercury(II) halides
as per the following equation:
The role of intermolecular secondary bonding interac-
tions (SBIs) as associative forces and that of intramolecular
SBIs in the stability and reactivity of organotellurium com-
pounds has been a subject of continuous investigations
since the time of Alcock’s observations and reviewed peri-
odically [1–3]. The latter interactions also appear to influ-
*
Corresponding author.
ð1Þ
E-mail address: akschauhan2003@yahoo.co.in (A.K.S. Chauhan).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.01.034

A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
1955
Formation of the transmetallation (reaction 1b) [4] and
inclusion products (reaction 1d) [5] involve cleavage of a
Te–C bond and have been suggested to be the consequence
of intramolecular 1,5-Teꢀ ꢀ ꢀN(O) interactions leading to
weakening of the trans Te–C bond. The 1:1 adducts (reac-
tion 1a) are oligomeric and have been structurally charac-
terized in a few cases [6]. Comparatively, fewer cases of
the formation of 1:2 monomeric complexes, HgX2(R2Te)2
(reaction 1c), have been observed and surprisingly none ap-
pears to have been crystallographically characterized so
far. In this communication the synthesis and structural
characterization of functionalized diorganotellurides
involving 1,4-type intramolecular Te(II)ꢀ ꢀ ꢀN interactions
and their 1:2 complexes with mercury(II) halides are dis-
cussed. Our interest in 1,4-type intramolecular SBIs stems
from a recent observation [7] that 1,4-Teꢀ ꢀ ꢀO interactions
are present in the Te(IV) compounds (4-RC6H4COCH2)2-
TeX2, but do not exist in the corresponding tellurides (4-
RC6H4COCH2)2Te, which are stabilized by intermolecular
Teꢀ ꢀ ꢀTe interactions in the solid-state. On the other hand,
1,5-Teꢀ ꢀ ꢀN(O) intramolecular SBIs have been found to be
present in both Te(IV) and Te(II) derivatives. We were
therefore interested to know (i) if 1,4-Te(IV)ꢀ ꢀ ꢀN intramo-
lecular interactions observed in the unsymmetrical diorg-
anotellurium dihalides (4-MeOC6H4)[2-(4,40-NO2C6H4-
CHNC6H3Me)]TeX2, R(SB)TeX2 [8], are retained in the
corresponding diorganotellurides, R(SB)Te and (ii) if such
an interaction also leads to weakening of Te–C bond trans
to the nucleophilic nitrogen atom in the telluride and (iii) if
so, is path (b) or (d) (Eq. (1)) followed. If formed, solid-
state structural characterization of the 1:2 adduct (path
1c) was also an incentive due to the lack of previous crys-
tallographic studies. An added interest in this study was
investigation of the solid-state molecular packing of com-
pounds 1a–c, which are organotellurium(II) derivatives of
4-nitro-40-methylbenzylideneaniline (NMBA), an organic
substrate known to possess second-order non-linear
(NLO) properties [9].
2. Results and discussion
The asymmetrical tellurides 1a–c were prepared by the
bisulfite reduction of the corresponding dichlorides, (4-
RC6H4)(SB)TeCl2. All the three tellurides are sharp melting
red crystalline solids which are soluble in ether, dichloro-
methane and chloroform. The IR spectra of 1a–c show an
absorption band at ꢁ1586 cmꢂ1 due to m(C@N) while the
1H NMR spectra consist of, in addition to CH3/OCH3
and/or aryl protons, a low field (ꢁ8.7 ppm) signal for the
methine proton. In the 13C NMR spectra the methine carbon
atom appears at ꢁ144 ppm (Table 1). The signal at
ꢁ123 ppm can be assigned to the tellurated C atom of the
nitrogen ring which is, as expected, deshielded compared
to the free Schiff base (111.1 ppm). 125Te chemical shifts of
the tellurides 1a–c and their mercury(II) halide complexes
are listed in Table 2 which also includes data on the three
bis(4-substituted benzoylmethyl)tellurides (preparation
and characterization of which have been reported earlier
Table 1
13C NMR data of tellurides 1 and their HgX2 complexes 2 and 3
4
5
7
3
2
8
14
11
9
6
13
12
N
1
20
17
Te
10
19
18
15
16
Y 21
Y = H, Me, OMe
Entry no.
1a
21.2
2a
20.6
3a
20.6
1b
2b
3b
20.7
21.0
1c
21.2
2c
20.7
3c
20.7
C7
C21
C15
C3
21.1
21.5
20.6
21.0
55.2
102.8
115.8
124.0
128.2
129.4
132.9
54.9
102.7
116.3
123.7
128.8
129.5
132.2
54.8
102.3
116.0
123.7
128.3
129.4
132.0
113.6
115.7
124.1
128.8
129.5
129.9
113.2
116.1
122.3
128.3
129.6
132.3
135.3
138.4
141.1
140.5
146.1
148.7
155.8
138.8
113.2
116.1
122.4
128.3
129.4
132.2
135.4
138.4
141.1
140.6
146.1
148.8
155.9
138.8
109.4
115.5
124.0
128.2
129.4
131.0
109.0
116.1
123.8
128.1
129.4
131.9
138.3
138.4
140.9
141.2
146.0
148.8
155.9
139.0
109.2
116.6
122.7
128.3
128.6
131.9
137.6
138.6
141.3
141.0
146.2
148.9
156.5
138.7
C1
C10,11,13,14
C4
C9
C5
C6
139.3
141.4
141.4
146.5
149.2
154.3
139.3
139.0
141.5
141.5
146.5
146.5
154.2
139.0
139.2
141.4
143.3
146.3
146.3
154.8
160.4
138.5
141.1
142.1
146.1
148.7
156.3
160.2
138.4
141.1
142.3
145.9
148.8
155.8
160.1
C16,17,19,20
C2
C12
C8
C18

1956
A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
Table 2
ter than the halide resulting in the formation of 1:2 adducts
instead of 1:1, which invariably involve bridging halide
ligands. However, quantitative displacement of 1c from
3c by PPh3, clearly suggests that the tertiary phosphine
(pKa 2.73) [10] is a stronger donor than the telluride
ligands. Such a displacement reaction thereby provides a
route to purify the tellurides, at least in case of 1. The IR
spectrum of 2c contains a sharp signal corresponding to
C@N at 1610.3 wave number, which is somewhat higher
than that in the telluride 1c (1586.5). There is little change
Solution (d6-DMSO) and solid-state 125Te NMR chemical shifts for some
tellurides and HgX2 complexes 2 and 3
Compound
d (ppm)
diso (ppm)
(PhCOCH2)2Te
484
487
493
593
575
564
572
559
533
573
556
538
(4-MeC6H4COCH2)2Te
(4-MeOC6H4COCH2)2Te
Ph(SB)Te (1a)
573
574
4-MeC6H4(SB)Te (1b)
4-MeOC6H4(SB)Te (1c)
[Ph(SB)Te]2HgCl2 (2a)
[4-MeC6H4(SB)Te]2HgCl2 (2b)
[4-MeOC6H4(SB)Te]2HgCl2 (2c)
[Ph(SB)Te]2HgBr2 (3a)
[4-MeC6H4(SB)Te]2HgBr2 (3b)
[4-MeOC6H4(SB)Te]2HgBr2 (3c)
438, 467
417
1
in the methine H NMR chemical shift between tellurides
and the mercury adducts. The solution 125Te NMR spectra
of 2a–c and 3a–c show a single resonance which are slightly
more shielded (by between 16 and 31 ppm) than the tellu-
rides 1a–c. Solid-state 125Te CP MAS NMR of 2a shows
two isotropic shifts at 438 and 467 ppm, which is consistent
with the crystal structure (vide infra). Only one isotropic
shift is observed for 2c at 417 ppm, indicating that the
two tellurium atoms are symmetry related, as in the crystal
structure of the bromine analogue, 3c. For both 2a and 2c,
the solid-state 125Te NMR signals are shifted by between
105 and 134 ppm to lower frequency than the solution state
signals, most likely as a result of the presence of intermo-
lecular interactions in the solid-state.
[7b]). 125Te NMR spectra of all the tellurides (Table 2) con-
sist of a single resonance indicating that the asymmetric mol-
ecules 1a–c do not undergo disproportionation to the
corresponding symmetric species in solution. In accordance
with the increased electron density around Te in the tellu-
rides, the 125Te NMR chemical shifts for the tellurides are
shifted to lower frequency in comparison to the Te(IV) diha-
lides [8] and also appear to follow the expected trend of alkyl
tellurides, [(4-RC6H4COCH2)2Te] being lower than the aryl
tellurides 1a–c. The 125Te CP MAS NMR spectra of
Ph(SB)Te (1a) and 4-MeC6H4(SB)Te (1b) revealed isotropic
chemical shifts at 573 and 574 ppm, respectively, which are
close to those observed for their DMSO solutions.
The tellurides (1a–c) are readily oxidized by SO2Cl2, Br2
and I2 at 0 ꢁC to the corresponding Te(IV) dihalides, [4-
RC6H4(SB)TeX2], which had earlier been prepared by a
transmetallation reactions between (SB)HgCl and (4-
RC6H4)TeCl3 (in the case of X = Cl) or by the halide
exchange between (4-RC6H4)(SB)TeCl2 and KBr or KI.
Reactions with interhalogens (IX; X = Cl, Br) afford the
respective mixed halides (4-RC6H4)(SB)TeIX, which tend
to disproportionate in solution on standing. Surprisingly,
the pseudo halogen, thiocyanogen failed to react with 1a–
c at room temperature.
Presence of the 1,4-Teꢀ ꢀ ꢀN coordinative interaction
(vide infra) in hybrid tellurides 1a–c is also expected to
enhance (at least marginally) the electron density at the
Te center. Reactions of 1a–c were therefore, carried out
with Pt(II) and Hg(II) halides. Reactions with mercury
halides afforded the pale orange crystalline adducts
HgX2[4-RC6H4(SB)Te]2, 2a–c (X = Cl) and 3a–c (X = Br)
but PtCl2(PhCN)2 failed to react in refluxing chloroform.
Attempts to prepare the 1:1 adduct by reacting equimolar
quantities of 1a–c and HgCl2 failed, producing only 2a–c
and unreacted HgCl2. This is interesting as most of the tel-
lurides either afford 1:1 adduct or both 1:1 and 1:2 adducts
with HgX2. Even heating of the adducts 2, 3 in refluxing
chloroform does not lead to cleavage of Te–C bond as
reported in case of adducts formed by tellurides that
involve 1,5-Teꢀ ꢀ ꢀN(O) intramolecular interactions. It
appears that the r-donor strength of the tellurides 1 is bet-
2.1. Crystal structures of 1b and 1c
ORTEP diagrams of the molecular structures of 1b and
1c are shown in Fig. 1 and the relevant bond parameters
included in Table 3. The Te–C bond lengths and the
included angle in 1b and 1c are characteristic of diaryltellu-
rides and their solid-state molecular structures are almost
superimposable, differing only in the orientation of the
nitro-substituted benzene ring. An interesting feature of
the molecular structures of these tellurides is the presence
of a 1,4-type intramolecular SBI between Te and the imine
˚
N atoms. The fact that the Teꢀ ꢀ ꢀN distance (2.924(4) A in
˚
1b, 3.107(4) A in 1c) is smaller than the sum of their van
˚
der Waals radii (3.61 A) is not a mere geometrical conse-
quence.1 The attractive interaction between Te(II) and the
ortho substituted azomethine nitrogen atom becomes obvi-
ous from the bending of N1–C2 and Te–C1 bonds towards
each other resulting in the appreciable angular distortions
in Te–C1–C2 and N1–C2–C1 bond angles that are reduced
to 114.2(3), 113.9(3)ꢁ in 1b and 116.0(3), 117.5(3)ꢁ in 1c
compared to the ideal value of 120ꢁ. The Te–C15 bond trans
to Teꢀ ꢀ ꢀN is also coplanar with the four-membered hetero-
cyclic ring (distance of C15 from the Te, C1, C2, N1 mean
˚
˚
plane is 0.0671 A in 1b, 0.1166 A in 1c), although the C15–
Teꢀ ꢀ ꢀN1 angle is far from being linear (149.8(1)ꢁ in 1b,
145.5(1)ꢁ in 1c). In the diorganotellurium compounds
involving 1,5-Teꢀ ꢀ ꢀN/O SBIs, coplanarity of the trans Te–
C bond with the heterocyclic ring has invariably been
1
Teꢀ ꢀ ꢀN1 distance calculated from the observed Te–C1, C1–C2, C2–N1
bond lengths and assuming bond angles Te–C1–C2 and N1–C2–C1 each
to be 120ꢁ is 3.18 A in 1b and 3.23 A in 1c.
˚
˚

A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
1957
Fig. 1. Molecular structures showing 50% probability displacement ellipsoids and the crystallographic numbering scheme (a) 1b and (b) 1c.
Table 3
Selected bond parameters (A, ꢁ) for 1b, 1c, 2a and 3c
˚
1b 1c
2a
3c
X = A
X = B
2.773(1)
Hg–TeX
Hg–ClX
Te1–N1
Te1–C1
Te1–C15
N1–C2
2.800(1)
Hg–Te
Hg–Br
2.797(3)
2.656(2)
2.941(4)
2.110(4)
2.114(4)
1.411(5)
1.274(5)
1.402(5)
2.496(2)
2.898(7)
2.125(8)
2.104(8)
1.41(1)
1.26(1)
1.40(1)
2.457(2)
2.959(7)
2.102(8)
2.098(8)
1.41(1)
1.27(1)
1.39(1)
2.924(4)
2.122(4)
2.132(4)
1.425(5)
1.281(5)
1.406(6)
3.106(4)
2.144(5)
2.148(5)
1.430(6)
1.292(6)
1.437(5)
Te1–N1
Te1–C1
Te1–C15
N1–C2
N1–C8
C1–C2
N1–C8
C1–C2
TeA–Hg–TeB
TeX–Hg–ClA
TeX–Hg–ClB
ClA–Hg–ClB
Hg–Te–N1
Hg–Te–C1
Hg–Te–C15
N1–Te–C1
N1–Te–C15
C1–Te–C15
Te–N1–C2
108.67(2)
100.58(5)
116.09(5)
108.19(7)
78.9(1)
94.3(2)
102.0(2)
53.9(3)
150.0(2)
96.4(3)
78.2(4)
145.6(6)
120.1(7)
Te–Hg–Tei
Te–Hg–Br
Te–Hg–Bri
Br–Hg–Bri
Hg–Te–N1
Hg–Te–C1
Hg–Te–C15
N1–Te–C1
N1–Te–C15
C1–Te–C15
Te–N1–C2
Te–N1–C8
C2–N1–C8
137.29(1)
91.80(1)
110.59(1)
116.53(1)
85.32(6)
108.12(9)
102.9(1)
52.9(1)
147.8(1)
95.2 (1)
77.6(2)
161.1(3)
119.8(3)
117.14(5)
106.54(5)
88.5(1)
95.5(2)
99.2(2)
52.7(3)
149.1(2)
96.6(3)
76.8(4)
151.3(6)
119.8(7)
53.3(1)
149.8(1)
96.5(2)
78.6(2)
158.6(3)
122.5(3)
51.8(1)
145.5(1)
93.9(1)
74.8(2)
147.5(3)
118.8(4)
Te–N1–C8
C2–N1–C8
Symmetry operation used to generate equivalent atoms: (i) ꢂx, y, ꢂ0.5 ꢂ z.

1958
A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
observed and the C–Teꢀ ꢀ ꢀN/O triad is reported to attain an
almost linear alignment (C–Teꢀ ꢀ ꢀN/O angles fall in the
range 157–170ꢁ). Coplanarity of the C15–Te bond with
the N1–C2–C1–Te plane in 1b and1c makes nN ! rꢃ
interaction feasible but due to non-linearity of Nꢀ ꢀðꢀTTe–eC–Þ
C15 triad, the orbital overlap is insufficient to cause Te–C
bond cleavage upon interaction with mercury(II) halides.
Such SBIs, however, contribute to the overall stability of
low valent compounds of chalcogens as has been inferred
from ab initio MO and DFT calculations on intramolecular
1,4-type non-bonded interactions between oxygen and chal-
cogen elements [11]. Similar 1,4-Teꢀ ꢀ ꢀN intramolecular
SBIs among the other structurally characterized diorgano-
tellurides with more flexible ethylene spacers between tellu-
rium and nitrogen was either absent or not looked into [12].
The crystal structures of 1b and 1c are devoid of any
intermolecular SBIs involving Te(II), which appears to be
due to the reduced Lewis acidity of tellurium center (as
compared to the corresponding Te(IV) dihalides [8]) as well
as its involvement in the intramolecular Teꢀ ꢀ ꢀN interaction.
The supramolecular architecture in the crystalline phase of
1b formed under self-assembly conditions represents a fasci-
nating case of molecular tectonic approach [13] of crystal
engineering. Each molecule behaves as a multipoint self-
complimentary tecton (Chart 1, A) and the topological
properties of intermolecular reciprocatory C13–H13ꢀ ꢀ ꢀO2
interaction results in the formation of zero-dimensional
centrosymmetric dimers as the supramolecular synthon
(Chart 1, B) which is common among the organic molecular
crystals [14]. The other C19–H19ꢀ ꢀ ꢀO1 H-bond in coopera-
tion with the C8–H8ꢀ ꢀ ꢀp(CH@N) interaction organizes
these synthons into an extended array that bears a centre
of inversion. The C11–H11ꢀ ꢀ ꢀp(aryl) interactions then
weave these double stranded molecular chains into a
three-dimensional supramolecular motif (Fig. 2). In 1c, on
the other hand, interactions between the more acidic methyl
protons and p-electron density of Te-substituted benzene
ring or that of azomethine bond (methoxy)C–Hꢀ ꢀ ꢀp (Te
substituted C6H3/CH@N) appears to be the only molecular
associative forces responsible for the observed crystal lat-
tice. As the chances of forming a dimer using this particular
interaction in a reciprocal manner appear limited the
observed catemer seems to be the energetically favored
choice. The overall packing of molecules in both the tellu-
rides conforms to the centrosymmetric space groups P21/n
and P21/c, respectively. Consequently, all putative second-
order NLO effects (reported for the monoclinic modifica-
tion of NMBA, space group Pc) are nullified in case of 1b
and 1c which precludes their application as NLO materials.
2.2. Crystal structures of 2a and 3c
ORTEP diagrams of the molecular structures of 2a and
3c are shown in Fig. 3 and the relevant bond parameters
included in Table 3. The geometry of the HgX2Te2 units
in these complexes is distorted tetrahedral. The angular
distortion around the central Hg(II) atom in 2a is limited
over a small range, 100.16(5)–117.11(5)ꢁ and values of the
bond angles Cl–Hg–Cl, 108.19(7)ꢁ and Te–Hg–Te,
108.67(2)ꢁ are close to the ideal tetrahedral value. The
observed Hg–Cl and Hg–Te bond lengths are comparable
1
O
O
H
2
2
N
O
N
O
H
H
O
Te
2
H
N
H
1
C
H
N
2
3
O
3
B
A
Chart 1.
Fig. 2. View of the 1D Chain of 4-MeC6H4(SB)Te (1b) consisting of a pair of anti-parallel rows of molecules via C–Hꢀ ꢀ ꢀO and C–Hꢀ ꢀ ꢀp interactions.

A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
1959
Fig. 3. Molecular structures showing 50% probability displacement ellipsoids and the crystallographic numbering scheme (a) 2a and (b) 3c.
to the corresponding values reported for the HgCl2 complex
of chelating bis(telluride), 1,6-bis(2-butyltellurophenyl)-2,5-
diazahexa-1,5-diene [15]. The HgBr2Te2 unit in 3c com-
prises of two symmetry related (i = ꢂx, y, ꢂ0.5 ꢂ z) halves
with Hg–Br and Hg–Te bond distances of 2.656(2) and
It has been recognized that M–Cl moieties are good
anisotropic H-bond acceptors. The acceptor strength of
metal-bound Cl atoms towards O–H, N–H [16] and C–H
[17] donors parallels that of Clꢂ anion and the directional-
ity and predictability of intermolecular C–Hꢀ ꢀ ꢀCl(2–3)–M
interactions have been compared with coordinative cova-
lent interactions [18]. The crystal packings in the neutral
complexes 2a and 3c have, therefore, been analyzed to
ascertain the role of mercury-bound halogen atoms, if
any, in the formation of supramolecular motifs via weak
C–Hꢀ ꢀ ꢀX interactions. While the C4A–H4Aꢀ ꢀ ꢀCl1B inter-
action in 2a arrange the identically oriented molecules in
a row, the other reciprocal C8A–H8Bꢀ ꢀ ꢀCl1A interaction
connects two such anti-parallel rows to form zero-dimen-
sional dimers with a center of inversion between symmetry
related molecules from the two rows. The intermolecular
C–Hꢀ ꢀ ꢀO(nitro) interactions link these extended arrays into
three-dimensional motifs.
˚
2.797(3) A, respectively. Steric bulk of the Br atoms in this
complex, however, causes greater repulsion among electron
rich ligands and distorts the coordination tetrahedron of the
mercury atom considerably, resulting in a Te–Hg–Tei angle
as large as 137.29(1)ꢁ. Almost similar values for Hg–Te
bond lengths in the two independent molecules of 2b as well
as in 3c indicate insignificant role of the electronic factor of
halogen atoms attached to Hg(II) on its geometry. The
observed difference in the orientation of the ligand atoms
around the central mercury atoms in the two complexes
(2a and 3c) could be a manifestation of steric bulk of X
ligands together with the variation of nature and strength
of intermolecular SBIs in the solid-state.

1960
A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
Fig. 4. View of the 1D supramolecular motif comprising of C–Hꢀ ꢀ ꢀO interlinked pair of rows which are formed by a combination of coordinative Hg–Te
and C3–H3ꢀ ꢀ ꢀBr interactions of [4-MeOC6H4(SB)Te]2HgBr2 (3c).
The role of mercury bound bromine atoms in the forma-
tion of supramolecular structure in the crystal lattice of 3c
is equally important in context of recent strategies to com-
bine analogous C–Hꢀ ꢀ ꢀCl–M interaction with transition
metal coordination chemistry to create metal containing
supramolecular synthons for the molecular recognition
in the area of inorganic crystal engineering [19,20]. The
C–Hꢀ ꢀ ꢀBr intermolecular interaction in 3c appear to pos-
sess the desired directionality and significance for supramo-
lecular architecture. The one-dimensional supramolecular
motif formed by a balanced combination of coordinative
covalent (Hg–Te) and (C3–H3ꢀ ꢀ ꢀBr) SBIs in 3c (Fig. 4)
may be compared with the 1D directional coordination
network based upon self-assembly of a bridging ligand
and metal halide [21].
over SBIs involving Te in the formation of supramolecular
synthons. Identification of metal assisted C–Hꢀ ꢀ ꢀX–M
interactions in the crystal lattice of 2a and 3c, indicates that
these interactions, though weak in strength, possess the
desired directionality and predictability. Such observations
may be useful in designing the building blocks for crystal
engineering so as to achieve the dream of rationally con-
structing functionalized supramolecular architecture in
molecular solids, which is still a daunting task.
3. Experimental
3.1. Material and instruments
The organotellurium halides, 4-RC6H4(SB)TeCl2, were
prepared by transmetallation reactions between (SB)HgCl
and 4-RC6H4TeCl3, as reported earlier [8]. IBr and
(SCN)2 were prepared by literature methods whereas
iodine monochloride and methyl iodide were procured
from Merck (Germany) and were distilled before use. Melt-
ing points were recorded in capillary tubes and are uncor-
2.3. Conclusions
The tellurides 1 possess rare intramolecular 1,4-Teꢀ ꢀ ꢀN
interaction which is retained and does not lead to Te–C
bond cleavage upon coordination to mercury(II) halides
as observed earlier for some 1,5-Teꢀ ꢀ ꢀN(O) containing tel-
lurides. Complete displacement of 1 from adducts 2 by
PPh3, though not very surprising, is of interest as a route
to purify 1. The crystal packings of tellurides, 1b and 1c,
illustrate the dominance of C–Hꢀ ꢀ ꢀO/C–Hꢀ ꢀ ꢀp interactions
1
rected. H NMR spectra were recorded at 300.13 MHz in
CDCl3 on a Varian DRX 300 Spectrometer using TMS
as internal standard. Solution 13C (100.54 MHz) and
125Te (126.19 MHz) NMR spectra were recorded in d6-
DMSO on a JEOL Eclipse Plus 400 NMR spectrometer,

A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
1961
using Me4Si and Me2Te as internal standards. Solid-state
125Te (126.19 MHz) CP MAS NMR spectra were acquired
on the same instrument with a 6 mm MAS probe operating
at spinning frequencies between 5 and 10 KHz. Experimen-
tal condition: 1 ls pulse width, 5 s relaxation delay, 10000
transients. The isotropic chemical shifts are referenced
against Me2Te using solid Te(OH)6 as the secondary refer-
ence (diso 692.1, 685.5) [22]. IR spectra were examined as
KBr pellets using a Perkin–Elmer RX1 Spectrometer. Ele-
mental carbon, hydrogen and nitrogen analyses were per-
formed on a Carlo Erba 1108 make analyzer. Tellurium
was estimated volumetrically and the halogen content
gravimetrically as silver halide.
Found: C, 54.30; H, 3.52; N, 6.12; Te, 28.53%. IR (KBr,
1
cmꢂ1): 1590.2 (CH@N). H NMR (300.13 MHz, CDCl3,
25 ꢁC): d 2.40 (s, 3H, CH3), 7.23–8.37 (m, 12H, Arom),
8.75 (s, 1H, CH@N).
3.2.2. Reaction of tellurides, 1 with HgX2 (X = Cl, Br)
3.2.2.1. [4-MeOC6H4(SB)Te]2HgCl2 (2c). To a solu-
tion of 1c (1.9 g, 4 mmol) in acetonitrile (100 mL), mer-
cury(II) chloride (0.54 g, 2 mmol) in the same solvent
(50 mL) was added slowly. A yellow solid gradually sepa-
rated during the addition. After stirring for 3 h the solid
was filtered, washed with acetonitrile and dried. Light yel-
low solid was recrystallized from DMF to give orange yel-
low needles of 2c. Yield: 2.17 g, 89%. M.p.: 222 ꢁC. Anal.
Calc. for C42H36N4O6Cl2HgTe2: C, 41.37; H, 2.98; N,
4.59; Te, 20.93. Found: C, 41.50; H, 3.02; N, 4.40; Te,
20.21%. IR (KBr, cmꢂ1): 1610.3 (mH@N). 1H NMR
(300.13 MHz, CDCl3, 25 ꢁC): d 2.20 (s, 6H, 2CH3), 3.87
(s, 6H, 2OCH3), 6.81–8.36 (m, 22H, Arom), 8.57 (s, 2H,
2CH@N).
3.2. Synthesis
3.2.1. Reduction reactions
3.2.1.1. Synthesis of 4-MeOC6H4(SB)Te (1c). A solution
of 4-MeOC6H4(SB)TeCl2 (1.09 g, 2 mmol) in dichloro-
methane (50 mL) was shaken with an aqueous solution of
Na2S2O5 (0.57 g, 3 mmol) for 15 min. The organic layer
gradually turned reddish orange. It was separated, washed
(4 · 50 mL) with water and dried over anhydrous Na2SO4
overnight. Volatiles were removed under reduced pressure
and the residue was crystallized from chloroform/diethyl
ether to give red rhombus crystals of 1c. Yield: 0.7 g,
74%. M.p.: 120 ꢁC. Anal. Calc. for C21H18N2O3Te: C,
53.21; H, 3.83; N, 5.91; Te, 26.92. Found: C, 53.00; H,
3.96; N, 6.05; Te, 26.10%. IR (KBr, cmꢂ1): 1586.5
The following adducts were prepared similarly.
3.2.2.2. [4-MeC6H4(SB)Te]2HgCl2 (2b). Yield: 91%.
M.p.: 228 ꢁC. Anal. Calc. for C42H36N4O4Cl2HgTe2: C,
42.48; H, 3.06; N, 4.72; Te, 21.49. Found: C, 42.30; H,
1
3.11; N, 4.59; Te, 22.00%. H NMR (300.13 MHz, CDCl3,
25 ꢁC): d 2.22 (s, 6H, 2CH3), 2.42 (s, 6H, 2CH3), 6.87–8.35
(m, 22H, Arom), 8.56 (s, 2H, 2CH@N).
1
(CH@N). H NMR (300.13 MHz, CDCl3, 25 ꢁC): d 2.19
3.2.2.3. [Ph(SB)Te]2HgCl2 (2a). Yield: 78%. M.p.:
240 ꢁC. Anal. Calc. for C40H32N4O4Cl2HgTe2: C, 41.44;
H, 2.78; N, 4.83; Te, 22.01. Found: C, 41.90; H, 2.60; N,
(s, 3H, CH3), 3.86 (s, 3H, OCH3), 6.78–8.35 (m, 11H,
Arom), 8.55 (s, 1H, CH@N).
1
4.92; Te, 22.02%. H NMR (300.13 MHz, CDCl3, 25 ꢁC):
3.2.1.2. Synthesis of 4-MeC6H4(SB)Te (1b). A solution
of 4-MeC6H4(SB)TeCl2 (1.06 g, 2 mmol) in chloroform
and Na2S2O5 (0.57 g, 3 mmol) in water gave red crystals
of 1b by following the same procedure as in 1.1. Yield:
0.6 g, 66%. M.p.: 140 ꢁC. Anal. Calc. for C21H18N2O2Te:
C, 57.07; H, 3.96; N, 6.12; Te, 27.86. Found: C, 56.90; H,
4.09; N, 6.37; Te, 27.00%. IR (KBr, cmꢂ1): 1586.5
(CH@N). H NMR (300.13 MHz, CDCl3, 25 ꢁC): d 2.34
(s, 3H, CH3), 2.50 (s, 3H, CH3), 7.39–8.39 (m, 11H, Arom),
8.87 (s, 1H, CH@N).
d 2.21 (s, 6H, 2CH3), 6.87–8.34 (m, 24H, Arom), 8.58 (s,
2H, 2CH@N).
3.2.2.4.
2.17 g,
[4-MeOC6H4(SB)Te]2HgBr2
82%. M.p.:
(3c). Yield:
220 ꢁC. Anal. Calc. for
C42H36N4O6Br2HgTe2: C, 38.56; H, 2.77; N, 4.28; Te,
19.51. Found: C, 38.22; H, 2.59; N, 4.56; Te, 20.20%. H
1
1
NMR (300.13 MHz, CDCl3, 25 ꢁC): d 2.96 (s, 6H, 2CH3),
3.87 (s, 6H, 2OCH3), 6.79–8.36 (m, 22H, Arom), 8.57 (s,
2H, CH@N).
3.2.1.3. Synthesis of Ph(SB)Te (1a). Compound
Ph(SB)TeCl2 (0.9 g, 2 mmol) and Na2S2O5 (twofold) were
shaken in two phase solvent system (CH2Cl2/H2O) for 5
min. The organic layer slightly turned orange. It was sepa-
rated and washed (2 · 50 mL) with water. It was again
treated with Na2S2O5 thrice successively (single step reduc-
tion was avoided to prevent decomposition). The organic
layer was finely separated and dried over anhydrous
Na2SO4 for 1 h. The reaction mixture was concentrated
under reduced pressure and the residue was crystallized
from chloroform/petroleum ether to give red crystals of
1a. Yield: 0.55 g, 62%. M.p.: 118 ꢁC. Anal. Calc. for
C20H16N2O2Te: C, 54.11; H, 3.63; N, 6.31; Te, 28.74.
3.2.2.5. [4-MeC6H4(SB)Te]2HgBr2 (3b). Yield: 87%.
M.p.: 235 ꢁC. Anal. Calc. for C42H36N4O4Br2HgTe2: C,
39.52; H, 2.84; N, 4.39; Te, 19.99. Found: C, 39.80; H,
2.99; N, 4.28; Te, 19.67%. H NMR (300.13 MHz, CDCl3,
25 ꢁC): d 2.21 (s, 6H, 2CH3), 2.23 (s, 6H, 2CH3), 6.83–8.30
(m, 22H, Arom), 8.49 (s, 2H, CH@N).
1
3.2.2.6. [Ph(SB)Te]2HgBr2 (3a). Yield: 91%. M.p.:
236 ꢁC. Anal. Calc. for C40H32N4O4Br2HgTe2: C, 38.49;
H, 2.58; N, 4.49; Te, 20.44. Found: C, 38.22; H, 2.69; N,
1
4.68; Te, 20.90%. H NMR (300.13 MHz, CDCl3, 25 ꢁC):
d 2.23 (s, 6H, 2CH3), 6.86–8.32 (m, 24H, Arom), 8.59 (s,
2H, CH@N).

1962
A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
3.2.2.7. Attempted preparation of 1:1 adduct. Mercury(II)
chloride (1.08 g, 4 mmol) in acetonitrile (ꢁ80 mL) was
added slowly to a solution of 1c (1.9 g, 4 mmol) in acetoni-
trile (ꢁ100 mL). A light yellow solid gradually separated
during the addition. After stirring for 3 h the solid was fil-
tered, washed with acetonitrile and dried. It was found to
be 2c. The filtrate on concentration afforded unreacted
HgCl2 (0.5 g).
added dropwise to a solution of 1c (0.47 g, 1 mmol) in car-
bon tetrachloride (10 mL) with stirring. A dark solid grad-
ually formed which after 0.5 h, was collected by filtration,
washed with pet ether and characterized as 4-
MeOC6H4(SB)TeI2. Yield: 0.63 g, 86%. M.p.: 196 ꢁC (lit
[8], 196 ꢁC). Anal. Calc. for C21H18N2O3I2Te: C, 34.66;
H, 2.49; N, 3.85; I, 34.87; Te, 17.53. Found: C, 34.88; H,
2.54; N, 4.03; I, 34.52; Te, 17.07%.
3.2.3. Oxidative addition reactions of 1
3.2.3.3. Synthesis of 4-MeOC6H4(SB)TeICl. To the solu-
tion of 1c (0.47 g, 1 mmol) in carbon tetrachloride (20 mL)
was added a solution of iodine monochloride (0.81 g,
1.1 mmol) in carbon tetrachloride with stirring at room
temperature. A light yellow colored solid was obtained
which was filtered, washed with carbon tetrachloride and
recrystallized from chloroform to give yellow needles of
4-MeOC6H4(SB)TeICl. Yield: 0.44 g, 59%. M.p.: 216 ꢁC.
Anal. Calc. for C21H18N2O3IClTe: C, 39.64; H, 2.85; N,
4.40; ICl, 25.51; Te, 20.05. Found: C, 39.62; H, 2.69; N,
4.46; ICl, 26.03; Te, 21.07%. IR (KBr, cmꢂ1): 1593.5
3.2.3.1. Synthesis of 4-MeOC6H4(SB)TeBr2: 1c. (0.47 g,
1 mmol) was dissolved in carbon tetrachloride (20 mL) and
a solution of bromine (0.18 mL, 1.2 mmol) in the same sol-
vent was slowly added with stirring. A light yellow colored
solid separated which was filtered, dried and recrystallized
with CHCl3 to give 4-MeOC6H4(SB)TeBr2. Yield: 0.52 g,
82%. M.p.: 180 ꢁC (lit [8], 180 ꢁC). Anal. Calc. for
C21H18N2O3Br2Te: C, 39.80; H, 2.86; N, 4.42; Br, 25.21;
Te, 20.13. Found: C, 39.73; H, 2.64; N, 4.60; Br, 24.10; Te,
21.07%. IR (KBr, cmꢂ1): 1583.08 (CH@N). 1H NMR
(300.13 MHz, CDCl3, 25 ꢁC): d 2.36 (s, 3H, CH3), 3.94 (s,
3H, OCH3), 7.15–8.41 (m, 11H, Arom), 8.89 (s, 1H, CH@N).
1
(CH@N). H NMR (300.13 MHz, CDCl3, 25 ꢁC): d 2.34
(s, 3H, CH3), 3.92 (s, 3H, OCH3), 7.15–8.35 (m, 11H,
Arom), 8.87 (s, 1H, CH@N). 13C NMR: d 21.54, 55.61,
114.15, 116.46, 118.71, 124.27, 130.52, 130.09, 133.82,
137.30, 144.21, 156.60, 162.38. 125Te NMR: d 884.8 ppm.
3.2.3.2. Synthesis of 4-MeOC6H4(SB)TeI2. Iodine
(0.26 g, 1 mmol) in carbon tetrachloride (10 mL) was
Table 4
Crystal data and structure refinement for 1b, 1c, 2a and 3c
1b
1c
2a
3c
Formula
C
457.97
21H18N2O2Te
C21H18N2O3Te
473.97
Monoclinic
0.10 · 0.65 · 0.95
P21/c
9.1659(14)
22.191(3)
9.8526(15)
90
99.803(3)
90
1974.8(5)
4
1.594
148(2)
1.529
C40H32Cl2HgN4O4Te2
1159.39
Monoclinic
0.08 · 0.18 · 0.52
P21/n
15.334(2)
9.166(2)
28.156(1)
90
92.077(1)
90
3954.7(10)
4
C42H36Br2HgN4O6Te2
1308.36
Monoclinic
0.25 · 0.50 · 0.75
C2/c
30.254(6)
9.324(2)
14.926(3)
90
97.844(3)
90
4171.3(13)
4
2.083
103(2)
7.029
Formula weight (g molꢂ1
Crystal system
Crystal size (mm)
Space group
)
Monoclinic
0.10 · 0.45 · 0.85
P21/n
7.318(1)
13.558(3)
19.370(4)
90
96.686(3)
90
1908.7(6)
4
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
Dcalcd (Mg mꢂ3
T (K)
)
1.594
103(2)
1.575
904
1.947
93(2)
5.519
2200
l (mmꢂ1
F(000)
)
936
2472
h Range (ꢁ)
2.2–27.5
ꢂ8 6 k 6 9;
ꢂ16 6 l 6 17;
ꢂ23 6 h 6 25
13127
99.4
4355
3356
235
2.2–27.5
ꢂ11 6 k 6 11;
ꢂ28 6 l 6 25;
ꢂ12 6 h 6 12
14217
99.6
4510
4077
244
1.4–27.5
ꢂ19 6 k 6 19;
0 6 l 6 11;
0 6 h 6 36
12124
99.8
12124
10246
480
2.3–27.5
ꢂ39 6 k 6 35;
ꢂ12 6 l 6 11;
ꢂ19 6 h 6 18
14604
99.5
4765
4461
259
Index ranges
Number of reflections collected
Completeness to hmax (%)
Number of independent reflections/Rint
Number of reflection observed with (I > 2r(I))
Number of refined parameters
GOF (F2)
1.053
1.198
1.091
1.056
R1 (F) (I > 2r(I))
0.038
0.094
0.046
0.108
0.058
0.157
0.030
0.073
wR2 (F2) (all Data)
(D/r)max
<0.0001
1.708/ꢂ0.697
<0.0001
0.799/ꢂ1.174
0.0009(1)
2.157 (near Hg)/ꢂ1.491
(near Hg)
<0.0061(5)
2.812 (near Hg)/ꢂ2.486
(near Hg)
ꢂ3
˚
Largest difference in peak/hole (e A
)

A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
1963
3.2.3.4. Synthesis of 4-MeOC6H4(SB)TeIBr. A freshly
4. Supplementary material
prepared solution of iodine monobromide (0.21 g,
1.1 mmol) in carbon tetrachloride was slowly added to
the solution of 1c (0.47 g, 1 mmol) in the same solvent.
Orange red product separated during addition. It was fil-
tered, washed with carbon tetrachloride and recrystallized
with CHCl3 to give 4-MeOC6H4(SB)TeIBr. Yield: 0.43 g,
63%. M.p.: 190 ꢁC. Anal. Calc. for C21H18N2O3IBrTe: C,
37.05; H, 2.66; N, 4.11; IBr, 30.38; Te, 18.74. Found: C,
36.86; H, 2.54; N, 4.09; IBr, 31.03; Te, 18.07%. IR (KBr,
Crystallographic data (excluding structure factors) for
the structural analyses have been deposited with the Cam-
bridge Crystallographic Data Centre, CCDC Nos. 289963
(1b), 246744 (1c), 289962 (2a) and 289961 (3c) (Supporting
Information). Copies of this information may be obtained
free of charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (fax: +44 1223 336 033; e-mail:
deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
1
cmꢂ1): 1598.6 (CH@N). H NMR (300.13 MHz, CDCl3,
25 ꢁC): d 2.38 (s, 3H, CH3), 3.93 (s, 3H, OCH3), 7.01–
8.43 (m, 11H, Arom), 8.89 (s, 1H, CH@N). 13C NMR: d
21.53, 55.58, 115.98, 116.69, 124.30, 130.15, 131.72,
133.81, 140.41, 144.15, 156.24, 162.20. 125Te NMR: d
841.9 ppm.
Acknowledgements
The financial assistance by the University Grants Com-
mission, New Delhi, India is gratefully acknowledged. P.S.
is grateful to the Council of Scientific and Industrial Re-
search, New Delhi, India for the award of JRF.
3.2.4. Synthesis of 4-MeOC6H4(SB)TeCl2
To a solution of 1c (0.47 g, 1 mmol) in carbon tetrachlo-
ride (30 mL), sulfuryl chloride (0.5 mL) was added drop-
wise with stirring at 0 ꢁC. The reaction mixture was
allowed to come to the room temperature and stirred for
15 min. Concentration under reduced pressure and addi-
tion of pet-ether afforded the colorless crystalline 4-
MeOC6H4(SB)TeCl2. Yield: 0.42 g, 70%.
4-MeC6H4(SB)TeCl2 and Ph(SB)TeCl2 were prepared
similarly from 1b and 1a, respectively, in 70–75% yield.
All these dichlorides, 4-RC6H4(SB)TeCl2 were authenti-
cated by their melting points and IR spectra [8].
References
[1] N.W. Alcock, Adv. Inorgchem. Radiochem. 15 (1972) 1.
[2] (a) Reviews concerning intermolecular SBIs involving Te: J. Zuker-
man-Schpector, I. Haiduc, Phosphorus Sulfur Silicon 171 (2001) 73;
(b) I. Haiduc, J. Zukerman-Schpector, Phosphorus Sulfur Silicon 171
(2001) 171;
(c) J. Zukerman-Schpector, I. Haiduc, Cryst. Eng. Commun. 4 (2002)
178;
(d) A.F. Cozzolino, I. Vergas-Baca, S. Mansour, A.H. Mahmoudkh-
ani, J. Am. Chem. Soc. 127 (2005) 3184;
(e) I. Vergas-Baca, T. Chivers, Phosphorus Sulfur Silicon Relat.
Elem. 164 (2000) 164.
Reaction of 3c with Ph3P. To a suspension of 3c (1.3 g,
1 mmol) in acetonitrile (20 mL) was added dropwise a solu-
tion of Ph3P (0.53 g, 2 mmol) in the same solvent at room
temperature. The reaction mixture changed to a dark red
suspension. It was filtered to remove the (Ph3P)2HgBr2
complex and washed with ether. The dark red filtrate on
concentration afforded 1c in quantitative yield (0.87 g,
1.9 mmol).
[3] (a) Reviews concerning intramolecular SBIs involving Te: W.R.
McWhinnie, Phosphorus Sulfur Silicon 67 (1992) 107;
(b) N. Sudha, H.B. Singh, Coord. Chem. Rev. 135/136 (1994) 469;
(c) W.R. McWhinnie, I.D. Sadekov, V.I. Minkin, Sulfur Reports 18
(1995) 295;
(d) V.I. Minkin, I.D. Sadekov, B.B. Rivkin, A.V. Zakharov, V.L.
Nivorozhkin, O.E. Kompan, Y.T. Struchkov, J. Organomet. Chem.
536–537 (1997) 233;
(e) I.D. Sadekov, V.I. Minkin, A.V. Zakharov, A.G. Sterikov, G.S.
Borodkin, S.M. Aldoshin, V.V. Tkachev, G.V. Shilov, F.J. Berry, J.
Organomet. Chem. 690 (2005) 103.
3.3. Crystallography
[4] (a) S.D. Apte, S.S. Zade, H.B. Singh, R.J. Butcher, Organometallics
22 (2003) 5473;
Single crystals of 1b, 1c, 2a and 3c suitable for X-ray
crystallography were obtained by slow evaporation of
chloroform solutions. Intensity data were collected on a
Bruker PS4 diffractometer with graphite-monochromated
(b) S.C. Menon, H.B. Singh, R.P. Patel, S.K. Kulshreshtha, J. Chem.
Soc., Dalton Trans. (1996) 1203.
[5] (a) M.R. Greaves, T.A. Hamor, B.J. Howlin, T.S. Lobana, S.A.
Mbogo, W.R. McWhinnie, D.C. Povey, J. Organomet. Chem. 420
(1991) 327;
(b) S.A. Mbogo, W.R. McWhinnie, T.S. Lobana, J. Organomet.
Chem. 384 (1990) 115.
[6] (a) B.L. Khandewal, A.K. Singh, V. Srivastava, Polyhedron 9 (1990)
2041;
(b) F.W.B. Einstein, C.H.W. Jones, T. Jones, R.D. Sharma, Inog.
Chem. 22 (1983) 3924.
[7] (a) A.K.S. Chauhan, A. Kumar, R.C. Srivastava, R.J. Butcher, J.
Organomet. Chem. 658 (2002) 169;
(b) A.K.S. Chauhan, A. Kumar, R.C. Srivastava, J. Beckmann, A.
Duthie, R.J. Butcher, J. Organomet. Chem. 689 (2004) 345;
(c) A.K.S. Chauhan, Anamika, A. Kumar, R.C. Srivastava, R.J.
Butcher, J. Organomet. Chem. 690 (2005) 313.
[8] A.K.S. Chauhan, Anamika, A. Kumar, R.C. Srivastava, R.J.
Butcher, J. Beckmann, A. Duthie, J. Organomet. Chem. 690 (2005)
1350.
˚
Mo Ka (0.7107 A) radiation. Data were reduced and
corrected for absorption using the programs SAINT and
SADABS [23]. The structures were solved by direct methods
and difference Fourier synthesis using SHELXS-97 imple-
mented in the program WINGX 2002 [24]. Full-matrix
least-squares refinements on F2, using all data, were car-
ried out with anisotropic displacement parameters applied
to all non-hydrogen atoms. Hydrogen atoms were
included in geometrically calculated positions using a rid-
ing model and were refined isotropically. Crystallographic
parameters and details of the data collection and refine-
ment are given in Table 4. Figures were created using
DIAMOND [25].

1964
A.K.S. Chauhan et al. / Journal of Organometallic Chemistry 691 (2006) 1954–1964
[9] P. Kerkoc, S. Lochran, R.T. Bailey, F.R. Cruickshank, D. Pugh,
J.N. Sherwood, A.J. Blake, J. Appl. Phys. 81 (1997) 624–630, and
references therein.
[14] G.R. Desiraju, Angew. Chem., Int. Ed. Engl. 34 (1995) 2311.
[15] N. Al-Salim, T.A. Hamor, W.R. McWhinnie, J. Chem. Soc., Chem.
Commun. (1986) 453.
[10] T. Allman, R.G. Goel, Can. J. Chem. 60 (1982) 717.
[11] (a) G.D. markham, C.L. Bock, M. Trachtman, C.W. Bock, J. Mol.
Struct. (Theochem.) 459 (1999) 187;
[16] G. Aullon, D. Bellamy, L. Brammer, E.A. Bruton, A.G. Orpen,
Chem. Commun. (1998) 653.
[17] P.K. Thallapally, A. Nangia, Cryst. Eng. Commun. 3 (2001) 114.
[18] V. Balamurugan, M.S. Hundai, R. Mukherjee, Chem. Eur. J. 10
(2004) 1683.
(b) O. Niyomura, S. Kato, S. Inagaki, J. Am. Chem. Soc. 122 (2000)
2132.
[12] (a) A.K. Singh, M. Kadarkaraisamy, G.S. Murthy, J. Srinivas, B.
Varghese, R.J. Butcher, J. Organomet. Chem. 605 (2000) 39;
(b) A.K. Singh, J. Sooriyakumar, M. Kadarkaraisamy, J.E. Drake,
M.B. Hursthouse, M.E. Light, R.J. Butcher, J. Chem. Res. (S)
(2001) 339;
[19] V. Balamurugan, R. Mukherjee, Cryst. Eng. Commun. 7 (2005)
337.
[20] V. Balamurugan, W. Jacob, J. Mukherjee, R. Mukherjee, Cryst. Eng.
Commun. 6 (2004) 396.
[21] A. Jouaiti, M.W. Hosseini, A.D. Cian, Chem. Commun. (2000)
1863.
[22] M.J. Collins, J.A. Ripmeester, J.F. Sawyer, J. Am. Chem. Soc. 109
(1987) 4113.
[23] SMART, SAINT, SADABS, Siemens Analytical X-ray Instruments, Inc.,
Madison, WI, USA, 1999.
[24] L.J. Farrugia, J. Appl. Crystallogr. 32 (1999) 837.
[25] DIAMOND V2.1d, Crystal Impact, K. Brandenburg, M. Berndt GbR.
Available from: <http://www.crystalimpact.de>.
(c) A.K. Singh, J. Sooriyakumar, R.J. Butcher, Inorg. Chim. Acta
312 (2001) 163;
(d) R. Kumar, A.K. Singh, R.J. Butcher, P. Sharma, Eur. J. Inorg.
Chem. (2004) 1107.
[13] (a) M.W. Hosseini, Acc. Chem. Res. 38 (2005) 313;
(b) M.W. Hosseini, Cryst. Eng. Commun. 6 (2004) 318;
(c) H. Henry, M.W. Hosseini, New J. Chem. 28 (2004) 897;
(d) S. Mann, Nature 365 (1993) 499.