N-[2-(4-methoxyphenyltelluro)ethyl]benzamide (L1) and N-[2-(4-methoxyphenyl telluro)propyl]phthalimide (L2): Synthesis and ligation with palladium(II), platinum(II) and ruthenium(II). Crystal structures of L1 and L2, the latter as a mixed crystal with L2H2

Article abstract of DOI:10.1016/S0277-5387(02)00831-8

The reactions of N-(2-chloroethyl)benzamide and N-[3- bromopropyl]phthalimide with ArTe^- Na⁺ generated in situ by borohydride reduction of Ar₂Te₂ have resulted in N-[2-(4-methoxyphenyltelluro)ethyl]benzamide (L¹) and N-[2-(4methoxyphenyltelluro)propyl] phthalimide (L²) respectively. The L¹ and L² both exhibit characteristic ¹H and ¹³C NMR spectra. The single crystal structures of L¹ and L², the latter as a mixed crystal with L²H₂ are determined by X-ray diffraction (XRD). The Te-C(alkyl) bond length is 2.140(8)/2.149(4) ? and longer than Te-C(aryl), 2.107(8)/2.123(5) ?. The complexes having stoichiometries [PdCl₂(L¹)] (1), [PtCl₂(L¹)](2), [(Phen)Pd(L¹)](ClO₄)₂ (3), [(DPPE)Pd(L¹)](ClO₄)₂ (4) and [RuCl₂(L²)₂] (5) were synthesized and characterized by elemental analyses, conductance and molecular weight measurements, NMR (¹H and ¹³C) and FT-IR spectra. The deshielding of CH₂Te (～ 0.2 ppm in ¹H NMR and up to 22 ppm in ¹³C{¹H} NMR) and NH signals (upto 0.8 ppm in ¹H NMR) of 1-4, with respect to those of free L¹ indicates that L¹ coordinates with Pd-Pt(II) as a (Te, N) ligand. The CH₂Te/CH₂N signals in ¹H and ¹³C NMR spectra of 5 appear deshielded (0.8/0.14 and 20/8 ppm, respectively), when compared with those of free L², indicating ligation of L² via Te and N.

Full text of DOI:10.1016/S0277-5387(02)00831-8

Polyhedron 21 (2002) 667–674
www.elsevier.com/locate/poly
N-[2-(4-Methoxyphenyltelluro)ethyl]benzamide (L1) and
N-[2-(4-methoxyphenyl telluro)propyl]phthalimide (L2): synthesis
and ligation with palladium(II), platinum(II) and ruthenium(II).
Crystal structures of L1 and L2, the latter as a mixed crystal with
L2H2
Ajai K. Singh a,*, J. Sooriyakumar a, M. Kadarkaraisamy a, John E. Drake b,
Michael B. Hursthouse c, Mark E. Light c, Raymond J. Butcher d
a Department of Chemistry, Indian Institute of Technology, New Delhi 110016, India
b Department of Chemistry and Biochemistry, Uni6ersity of Windsor, Windsor, Ont., Canada N9B 3P4
c Department of Chemistry, Uni6ersity of Southampton, Southampton SO17 1BJ, UK
d Department of Chemistry, Howard Uni6ersity, Washington, DC 20059, USA
Received 7 June 2001; accepted 3 January 2002
Abstract
The reactions of N-(2-chloroethyl)benzamide and N-[3-bromopropyl]phthalimide with ArTe− Na+ generated in situ by
borohydride reduction of Ar2Te2, have resulted in N-[2-(4-methoxyphenyltelluro)ethyl]benzamide (L1) and N-[2-(4-
1
methoxyphenyltelluro)propyl] phthalimide (L2) respectively. The L1 and L2 both exhibit characteristic H and 13C NMR spectra.
The single crystal structures of L1 and L2, the latter as a mixed crystal with L2H2 are determined by X-ray diffraction (XRD).
,
,
The TeꢀC(alkyl) bond length is 2.140(8)/2.149(4) A and longer than TeꢀC(aryl), 2.107(8)/2.123(5) A. The complexes having
stoichiometries [PdCl2(L1)] (1), [PtCl2(L1)](2), [(Phen)Pd(L1)](ClO4)2 (3), [(DPPE)Pd(L1)](ClO4)2 (4) and [RuCl2(L2)2] (5) were
synthesized and characterized by elemental analyses, conductance and molecular weight measurements, NMR (1H and 13C) and
FT-IR spectra. The deshielding of CH2Te (ꢀ0.2 ppm in H NMR and up to 22 ppm in 13C{1H} NMR) and NH signals (upto
1
0.8 ppm in H NMR) of 1–4, with respect to those of free L1 indicates that L1 coordinates with Pd–Pt(II) as a (Te, N) ligand.
1
The CH2Te/CH2N signals in 1H and 13C NMR spectra of 5 appear deshielded (0.8/0.14 and 20/8 ppm, respectively), when
compared with those of free L2, indicating ligation of L2 via Te and N. © 2002 Elsevier Science Ltd. All rights reserved.
Keywords: N-[2-(4-Methoxyphenyltelluro)ethyl]benzamide; N-[2-(4-Methoxyphenyl telluro)propyl]phthalimide; Palladium(II); Platinum(II);
Ruthenium(II); Complexes; Crystal structures
1. Introduction
amines [1,2,8,9] and pyridine derivatives [10]. However,
ligand chemistry of hybrid organotellurium donor con-
taining amide functionality is unknown so far [2–4].
Similarly the telluration of imide derivatives has been
reported [4] scantly. It was, therefore, thought worth-
while to design N-[2-(4-methoxyphenyltelluro)ethyl]-
benzamide (L1) and N-[2-(4-methoxyphenyltelluro)-
propyl] phthalimide (L2) and investigate their ligand
chemistry. The results of these investigations are re-
ported in this paper. Both the ligands are structurally
characterized. However, for L2, the crystal used was
found to be a mixed crystal of L2 and L2H2, with
The current interest in the chemistry of hybrid organ-
otellurium ligands (having other donor sites along with
Te) [1–7] is due to their obvious importance in under-
standing further the ligation of heaviest metalloid tel-
lurium vis a vis other well known donors. The
designing of (Tex, Ny) type of hybrid organotellurium
ligands has been carried out by tellurating aliphatic
* Corresponding author. Fax: +91-11-6862037.
E-mail address: aksingh@chemistry.iitd.ernet.in (A.K. Singh).
0277-5387/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0277-5387(02)00831-8

668
A.K. Singh et al. / Polyhedron 21 (2002) 667–674
occupancies of 40 and 60%, respectively. None of the
complexes could be structurally characterized due to
poor quality of their crystals. However, using their
spectroscopic (NMR and IR) data it can be readily
inferred that L1 and L2 both ligate as a (Te, N) donor
in all the complexes 1–5.
2. Experimental
The C and H analyses were carried out with a
Perkin–Elmer elemental analyzer 240 C. Tellurium was
estimated volumetrically [4]. The 1H and 13C{1H}
NMR spectra were recorded on a Bruker Spectrospin
DPX-300 NMR spectrometer at 300.13 and 75.47
MHz, respectively. IR spectra in the range 4000–250
cm−1 were recorded on a Nicolet Prote´ge 460 FT-IR
spectrometer as KBr and CsI pellets. The conductance
measurements were made in acetonitrile (concentra-
tionꢀ1 mM) using an ORION conductivity meter
model 162. The molecular weights (concentrationꢀ5
mM) in chloroform were determined with a Knauer
vapour pressure osmometer model A0280. The melting
points (m.p.) determined in open capillary are reported
as such. N-(2-Chloroethyl)benzamide and N-[3-bromo-
propyl]phthalimide obtained from Aldrich (USA) were
used as received. The reported methods were used to
synthesize [(Phen)PdCl2] [11,11a] and [(DPPE)PdCl2]
[11b].
Table 1
2.1. X-ray diffraction analysis
Crystal data and structure refinement for L1 and ‘L2’
The Bruker P4S X-ray diffractometer was used for
the data collection on L1, employing ꢀ–2q technique.
The unit cell was determined from 25 randomly selected
reflections using automatic search, index and least
square routines. Empirical absorption correction was
applied using SHELXA programme [12,12a]. The struc-
ture was solved by routine heavy atom/Fourier meth-
ods (using SHELXL 93 [12b]/SHELX 86 [12c]) and refined
by full-matrix least-squares on F2. The crystal and
refinement data of L1 are given in Table 1. For struc-
ture determination of ‘L2’ (mixed crystal of L2 and
L2H2, which are colourless plates) a suitable specimen
was mounted on a glass fibre and cell dimensions and
intensity data were recorded on an Enraf Nonius
KCCD diffractometer, with ƒ and ꢀ scans chosen to
give a complete asymmetric unit. The data collection
and cell refinement [13] gave cell constants correspond-
ing to an orthorhombic cell whose dimensions are given
in Table 1 along with other experimental parameters
An absorption correction was applied [14], which re-
sulted in transmission factors ranging from 0.9650 to
0.7744. The structures were solved by direct methods
[15]. All of the non-hydrogen atoms were treated an-
isotropically. During the course of the refinement, it
was found that oxygen O(2) was split over two posi-
tions. This was interpreted as resulting from the use of
a mixed crystal of L2 and L2H2. The rigidity of the
phthalimide system is apparently such that all atoms
are in identical positions in L2 and L2H2 with the
exception of the terminal oxygen, ꢁC(11)ꢀO(2B) in L2
and the hydroxyl oxygen, ꢁC(11)HꢀO(2A)H in L2H2.
The effect is an apparent disorder of this oxygen atom
L1
‘L2’
Empirical formula
C16H17NO2Te C18H18.2NO3Te
[(C18H17NO3Te)0.4
-
(C18 H18.2NO3 Te)0.6
424.14
150(2)
]
Formula weight
Temperature (K)
382.91
293(2)
0.71073
,
Wavelength (A)
0.71073
Crystal system
Space group
Orthorhombic Orthorhombic
P212121 Pbca
a=5.410(4) (A) 14.646(3) (A)
b=9.915(4) (A) 5.9656(12) (A)
c=28.760(3)
,
,
,
Unit cell dimensions
,
,
38. 213(8) (A)
,
(A)
3
,
Volume, (A )
Z
1542.6(15)
4
3338.7(12)
8
1.688
1.796
Dcalc (Mg m−3
)
1.649
1.929
Absorption coefficient
(mm−1
F(000)
)
752
1674
Crystal size (mm)
q Range for data
collection (°)
Reflections collected
Independent reflections
0.1×1.00×0.1 0.15×0.10×0.02
2.17–25.00
2.98–27.47
1630
1630
[Rint=0.000]
full-matrix
least-squares
on F2
10791
3627
[Rint=0.0684]
full-matrix
least-squares on F2
Refinement method
Data/restraints/parameters 1630/0/201
3627/0/214
0.895
Goodness-of-fit on F2
Final R indices
1.047
R1=0.0382,
wR2=0.0791
R1=0.0572,
wR2=0.0873
0.432 and
−0.389
R1=0.0394,
wR2=0.0688
R1=0.1211,
wR2=0.0864
0.494 and
−0.542
[F2\2/4|(F2)]
R indices (all data)
Largest diff. peak and
−3
,
hole (e A
)

A.K. Singh et al. / Polyhedron 21 (2002) 667–674
669
with the occupancy of O(2B):O(2A) of 0.4:0.6. Hydro-
gen atoms were included in idealized positions with
isotropic thermal parameters set at 1.2 times that of the
carbon and oxygen atom to which they were attached.
The parameters for final cycle of full-matrix least-
squares refinement of mixed crystal, ‘L2’ [16] are also
given in Table 1. The ORTEP diagram of L2 is displayed
in Fig. 3(a) and that of L2H2 in Fig. 3(b).
PdCl2: C, 34.29; H, 3.03; N, 2.50; Te, 22.86. Found: C,
34.35; H, 3.10; N, 2.84; Te, 21.93%. Mol. wt.: 550
(Calc. 560). 1H NMR (CDCl3, 25 °C) (l vs. TMS): 3.37
(bs, 2H, H1), 3.77 (s, 3H, OMe), 3.87 (bs, 2H, H2),
6.84–6.86 (d, 2H, ArH m to Te), 7.08 (bs, 1H, NH),
7.34–7.48 (m, 3H, ArH p and m to CO), 7.77–7.80 (d,
2H, ArH o to CO), 7.82–7.85 (d, 2H, ArH o to Te).
13C{1H} NMR (CDCl3, 25 °C) (l vs. TMS): 22.9 (C1),
38.1 (C2), 55.3 (OCH3), 105.1 (ArCꢀTe), 115.9 (ArC m
to Te), 127.3 (ArC m to CO), 128.5 (ArC p to CO),
131.7 (ArC o to CO), 133.5 (ArCꢀCO), 137.8 (ArC o to
Te), 161.5 (ArC p to Te), 167.8 (CO).
2.2. Synthesis of
N-[2-(4-methoxyphenyltelluro)ethyl]benzamide (L1)
The solution of bis(4-methoxyphenyl)ditelluride (1.87
g, 4 mmol) made in 50 cm3 of ethanol was refluxed
under oxygen free nitrogen atmosphere. Sodium boro-
hydride (0.5 g dissolved in 10 cm3 of 10% aqueous
NaOH) was added to it drop wise till it became colour-
less. N-(2-Chloroethyl)benzamide (1.46 g, 8 mmol) dis-
solved in 10 cm3 of ethanol, was added drop wise to the
refluxing colourless solution. The reaction mixture was
further refluxed for 1–2 h, cooled to 25 °C and poured
into ice cold water (200 cm3). L1 was extracted from it
into dichloromethane (100 cm3). The extract was
washed with water, dried over sodium sulfate and evap-
orated on a rotary evaporator, resulting in a yellowish
2.4. Synthesis of [PtCl2(L1)](2)
To a solution of K2[PtCl4] (0.17 g, 0.4 mmol) made in
10 cm3 of water, ligand L1 (0.15 g 0.4 mmol) dissolved
in 10 cm3 of acetone was added. The resulting mixture
was stirred for 1 h at r.t. and poured into 100 cm3 of
water. The complex 2 was extracted into chloroform
(100 cm3). The extract was dried over anhydrous
sodium sulphate, concentrated to ꢀ10 cm3 on a rotary
evaporator and mixed with hexane (15 cm3). The result-
ing precipitate of 2 was filtered, washed with hexane
and recrystallized from hexane–dichloromethane (1:1)
mixture. The yellow colored compound was separated,
filtered and dried in vacuo. Yield: 80%; m.p. 112–
113 °C (d) \M (V−1 cm2 mol−1) 36. Anal. Calc. for
C16H17O2NTePtCl2: C, 29.54; H, 2.61; N, 2.16 Te,
18.97. Found: C, 30.05; H, 2.84; N, 1.94; Te, 18.97%.
oil, which was dissolved in
a 1:2 mixture of
dichloromethane and petroleum ether (40–60 °C). The
solution was kept at 0–5 °C for 24 h. The fibrous white
crystals of L1 were filtered and dried in vacuo. Yield:
70%; m.p. 68–70 °C \M (V−1 cm2 mol−1) 5.3. Anal.
Calc. for C16H17O2NTe: C, 50.19; H, 4.44; N, 3.66; Te,
32.50. Found: C, 49.81; H, 4.58; N, 3.17; Te, 32.70%.
1
Mol. wt.: 641 (Calc. 649.3). H NMR (CDCl3, 25 °C)
(l vs. TMS): 3.39 (bs, 2H, H1), 3.74 (s, 3H, OMe), 3.86
(bs, 2H, H2), 6.83–6.86 (d, 2H, ArH m to Te), 7.01 (bs,
1H, NH), 7.36–7.47 (m, 3H, ArH p and m to CO),
7.78–7.84 (m, 4H, ArH o to CO and o to Te). 13C{1H}
NMR (CDCl3, 25 °C) (l vs. TMS): 29.7 (C1), 39.6 (C2),
55.5(OCH3), 104.8 (ArCꢀTe), 115.9 (ArC m to Te),
127.3 (ArC m to CO), 128.5 (ArC p to CO), 131.7 (ArC
o to CO), 133.5 (ArCꢀCO), 137.8 (ArC o to Te), 161.5
(ArC p to Te), 167.8 (CO).
1
Mol. wt.: 375 (Calc. 382). H NMR (CDCl3, 25 °C) (l
vs. TMS) 3.00–3.04 (t, 2H, H1), 3.76–3.82 (m, 5H, H2
and OMe), 6.52 (bs, 1H, NH), 6.72–6.75 (d, 2H, ArH
m to Te), 7.35–7.49 (m, 3H, ArH p and m to CO),
7.62–7.64 (d, 2H, ArH o to CO), 7.69–7.72 (d, 2H,
ArH o to Te). 13C{1H} NMR (CDCl3, 25 °C) (l vs.
TMS): 8.1 (C1), 41.5 (C2), 54.9 (OCH3), 99.3 (ArCꢀTe),
115.2 (ArC m to Te), 126.8 (ArC m to CO), 128.2 (ArC
p to CO), 131.7 (ArC o to CO), 134.1 (ArCꢀCO), 140.8
(ArC o to Te), 160.9 (ArC p to Te), 167.1 (CO).
2.5. Synthesis of [(Phen)Pd(L1)](ClO4)2 (3)
2.3. Synthesis of [PdCl2(L1)] (1)
Solution of AgClO4 (0.08 g, 0.4 mmol) made in
methanol (10 cm3) was mixed with the slurry of
[(Phen)PdCl2] (0.07 g, 0.2 mmol) prepared in chloro-
form (10 cm3). The resulting mixture was stirred for 30
min at r.t., mixed with a solution of ligand L1 (1.52 g,
0.4 mmol) made in chloroform (10 cm3) and stirred
further for 2 h. The white precipitate of AgCl was
filtered off. The filtrate was concentrated to 10 cm3 on
a rotary evaporator and mixed with hexane (10 cm3).
The resulting precipitate of 3 was filtered, washed with
hexane–chloroform (5:1) mixture, recrystallized from
acetonitrile and dried in vacuo. Yield: 68%; m.p. 114–
115 °C (d) \M (V−1 cm2 mol−1) 250. Anal. Calc. for
The [(C6H5CN)2PdCl2] (0.49 g, 1 mmol) dissolved in
20 cm3 of dichloromethane was mixed with a solution
of ligand L1 (0.38 g, 1 mmol) made in 10 cm3 of
dichloromethane with vigorous stirring. The mixture
was further stirred for 2 h at room temperature (r.t.),
concentrated to 7–8 cm3 on a rotary evaporator and
mixed with hexane (5 cm3). The resulting brown precip-
itate of 1 was filtered, washed with diethylether, recrys-
tallized from chloroform–hexane (1:2) mixture and
dried in vacuo. Yield: 85%; m.p. 84–85 °C (d) \M
(V−1 cm2 mol−1) 30 Anal. Calc. for C16H17O2NTe-

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A.K. Singh et al. / Polyhedron 21 (2002) 667–674
C30H25N3TePdCl2 O10: C, 38.66; H, 2.87; N, 4.84; Te,
14.70. Found: C, 38.88; H, 2.36; N, 4.79; Te, 14.10%.
Mol. wt.: 286 (Calc. 868). H NMR (CDCl3, 25 °C) (l
mol−1) Anal. Calc. for C18H17O3NTe: C, 51.13; H,
4.02; N, 3.31; Te 30.18. Found: C, 50.60; H, 4.41; N,
1
1
3.53; Te, 30.77%. Mol. wt.: (Calc.). H NMR (CDCl3,
vs. TMS): 3.42 (bs, 2H, H1), 3.77–3.81 (m, 5H, H2 and
OMe), 6.66–6.62 (d, 2H, ArH m to Te), 6.95 (bs, 1H,
NH), 7.33–7.46 (m, 3H, ArH p and m to CO), 7.62–
7.80 (m, 8H, ArH o to CO, o to Te, Ha and Hb of
phen), 8.46–8.49 (m, 2H, Hc of phen), 9.17–9.19 (m,
2H, Hd of phen).13C{1H} NMR (CDCl3, 25 °C) (l vs.
TMS): 19.3 (C1), 39.2 (C2), 55.1 (OCH3), 104.0
(ArCꢀTe), 115.9 (ArC m to Te), 127–138(ArC of
phen+ArC o to Te+ArC of benzamide), 160.5 (ArC
p to Te), 168.1 (CO).
25 °C) (l vs. TMS): 2.06–2.15 (q, 2H, H2ꢀC7); 2.74–
2.80 (t, 2H, H2CꢀTe); 3.72–3.75 (t, 2H, H2CꢀN); 3.76
(s, 3H, OCH3); 6.73–6.76 (d, 2H, ArH m to Te);
7.67–7.73 (m, 4H, ArH of phthalimide ring); 7.82–7.84
(d, 2H, ArH, o to Te). 13C{1H} NMR (CDCl3, 25 °C)
(l vs. TMS): 4.5 (C6), 30.6 (C7), 39.7 (C8), 55.1 (C1);
100.2 (C5), 115.2 (C3), 123.2 (C11), 132.2 (C10), 133.5
(C12), 141.3 (C4), 159.8 (C2), 168.3 (C9).
2.8. Synthesis of [RuCl2(L2)2] (5)
2.6. Synthesis of [(DPPE)Pd(L1)](ClO4)2 (4)
Solution of RuCl3·xH2O (0.21 g, 1 mmol) in 20 cm3
of methanol was mixed with L2 (0.86 g, 2 mmol)
dissolved in 20 cm3 of dichloromethane. The mixture
was stirred for 3 h at r.t., filtered and concentrated to a
solid residue on a rotary evaporator. The residue was
dissolved in acetonitrile (10 cm3) and resulting solution
filtered. The filtrate was layered with 20 cm3 of diethyl
ether and kept at 0 °C for 48 h. The pale brown needle
shaped crystals were separated and dried under vacuo.
Yield: 55%; m.p. 168–169 °C. \M 29.8 (V−1 cm2
mol−1) Anal. Calc. for C36H34O6N2Te2RuCl2: C, 42.49;
H, 3.34; N, 2.76; Te 25.08. Found: C, 43.10; H, 2.42; N,
2.56; Te, 25.58%. Mol. wt.: 988.4 (Calc. 1017.5). 1H
NMR (CDCl3, 25 °C) (l vs. TMS): 2.52–2.62 (q, 2H,
H2ꢀC7); 3.62–3.69 (t, 2H, H2CꢀTe); 3.86–3.93 (t, 2H,
H2CꢀN+OCH3); 7.03–7.06 (d, 2H, ArH m to Te);
7.77–7.88 (m, 4H, ArH of phthalimide ring); 8.03–8.08
(d, 2H, ArH, o to Te). 13C{1H} NMR (CDCl3, 25 °C)
(l vs. TMS): 25.0 (C6), 38.3 (C7), 47.5 (C8), 55.6 (C1),
115.7 (C3), 123.5 (C11), 131.9 (C10), 134.2 (C12), 135.0
(C3), 162.3 (C2), 168.3 (C9).
Solution of [(DPPE)PdCl2] (0.12 g, 0.2 mmol) in
chloroform (10 cm3) was mixed with AgClO4 (0.08 g,
0.4 mmol) dissolved in 5 cm3 of methanol. The mixture
was stirred for 30 min. The AgCl was filtered off. The
L1 (0.76 g, 0.2 mmol) dissolved in chloroform (10 cm3)
was added to the filtrate. The mixture was stirred for 2
h at r.t., concentrated on a rotary evaporator to 10 cm3
and mixed with hexane (20 cm3). The resulting precipi-
tate of 4 was filtered, recrystallized from chloroform–
diethylether mixture and dried in vacuo. Yield: 70%;
m.p. 96–97 °C (d) \M (V−1 cm2 mol−1) 246 Anal.
Calc. for C42H41O10NP2TePdCl2: C, 46.34; H, 3.77; N,
1.28; Te, 11.77. Found: C, 46.04; H, 4.09; N, 1.53; Te,
11.60%. Mol. wt.: 359 (Calc. 1087.5). 1H NMR (CDCl3,
25 °C) (l vs. TMS): 2.76–2.94 (m, 4H,CH2ꢀP), 3.55
(m, 2H, H1), 3.67 (s, 3H, OMe), 3.81–3.83 (m, 2H, H2),
6.49–6.52 (d, 2H, ArH m to Te), 7.02–7.82 (m, 28H,
NH, ArH of DPPE, ArH o to Te, ArH of benzamide).
13C{1H} NMR (CDCl3, 25 °C) (l vs. TMS): 16.1 (C1),
24.0 (CH2ꢀP), 38.5 (C2), 57.3 (OCH3), 103.8 (ArCꢀTe),
115.4 (ArC m to Te), 127.3–138.0 (ArC of DPPE+
ArC o to Te+ArC of benzamide), 161.5 (ArC p to Te),
167.6 (CO).
3. Results and discussion
The ligands L1 and L2 and their complexes were
prepared according to the reaction given in Eqs. (1)–(6)
2.7. Synthesis of L2
The solution of N-[3-bromopropyl]phthalimide (1.44
g, 4.2 mmol) made in 10 ml of THF was added to a
refluxing colourless solution of ArTe−Na+ generated in
situ by the procedure given in Section 2.2. The mixture
was refluxed further for 1 h, cooled to r.t. and poured
into 100 cm3 of water. L2 was extracted from it into 50
cm3 of CH2Cl2. The extract was dried over Na2SO4,
concentrated to 5 cm3 on a rotary evaporator and
mixed with petroleum ether (40–60 °C). The resulting
white crystalline solid L2 was filtered, washed with
petroleum ether (40–60 °C) and dried in vacuo. The
single crystals of L2 were grown from a mixture (8:2) of
dichloromethane and petroleum ether (40–60 °C).
Yield: 80%; m.p. 102–103 °C (d) \M 0.8 (V−1 cm2
ArTeNa+C6H5CONHCH2CH2Cl“L1 or L2+NaCl
(1)
or
(C6H5CN)2PdCl2+L1“[PdCl2(L1)](1)+2C6H5CN
(2)
K2PtCl4+L1“[PtCl2(L1)](2)+2KCl
(3)

A.K. Singh et al. / Polyhedron 21 (2002) 667–674
671
[(Phen)PdCl2]+2AgClO4+L1
“[(Phen)Pd(L1)](ClO4)2(3)+2AgCl−¡
[(DPPE)PdCl2]+2AgClO4+L1
“[(DPPE)Pd(L1)](ClO4)2(4)+2AgCl−¡
RuCl3·xH2O+2L2“[RuCl2·(L2)2](5)
that ligation of L1 is through nitrogen also. However, in
the spectra of 1–4, the band having major contribution
from CO was found almost unchanged with respect to
that of L1, indicating that CO is not involved in coordi-
nation. In IR spectra of 3 and 4 perchlorate bands
appear around 1100 (anti-symmetric stretching) and
620 cm−1 (anti-symmetric bending) suggesting that per-
chlorate ions are not coordinated. In the IR spectrum
of L2 w(CO) appearing at 1696 cm−1 remains un-
changed on the formation of 5.
(4)
(5)
(6)
1
In H NMR spectrum of L1, the broad NH signal
appearing at 6.52 ppm disappears with a D2O shake. It
shows a downfield shift (ꢀ0.2–0.8 ppm) in the spectra
of 1–4 (relative to free L1) indicating that L1 ligates
with Pd–Pt(II) through N. The signals of CH2Te and
aryl protons (o and m to Te) are observed deshielded
1
(ꢀ upto 0.2 ppm) in H NMR of 1–4, with respect to
those of free L1, supporting the ligation of L1 through
Since BH−4 was taken in slight excess to avoid oxida-
tion of ArTe− back to Ar2Te2, it probably reduced one
ꢁCꢂO group resulting in L2H2, which formed with L2
a mixed crystal, ‘L2’ (with occupancies 60 and 40%,
respectively), selected by chance for X-ray data collec-
tion. However, the percentage of L2H2 in the sample of
1
Te. However, signals of CH2N in H NMR spectra of
1–4 appear virtually unaffected when compared with
those of free L1. This suggests that probably a N···Te
secondary interaction exists in L1 and on coordination
with Pd–Pt it is replaced by N“M bond. The broad-
ness of signals of aliphatic protons in the spectra of 1–4
may be attributed to the coexistence of tautomers given
below.
1
L2 was below the detection limit of H NMR spectra.
In 13C{1H} NMR spectra of 1–4, the signals of C1
and aryl C ipso to Te were found deshielded (upto ꢀ22
and 6 ppm, respectively) with respect to those of free
L1. However, signal of C2 is found unaffected or mar-
ginally shielded (with respect to that of L1), supporting
the existence of N···Te secondary interaction in L1. The
signal of ꢀCONHꢀ is found unshifted in 13C{1H} NMR
The ligands L1 and L2 and complexes 1–5 are soluble
in common organic solvents. The complex 5 shows the
sign of decay after 1 week even in nitrogen atmosphere.
All other compounds were found stable under ambient
conditions. The stoichiometries of the complexes have
been authenticated by their elemental analyses. The
molar conductance values (in acetonitrile at ꢀ1 mM
concentration level) and molecular weights of 3 and 4
(ꢀone third of calculated values) suggest that they are
1:2 electrolytes [17]. For 1, 2 and 5 the molar conduc-
tance values (\M) have been found to be much lower
than that of a 1:1 electrolyte [17]. Their observed
molecular weights were found to be very close to the
calculated ones.
1
of 1–4. The H and 13C{1H} NMR spectra of L2 are
characteristic and their assignments are supported by
HETCOR spectrum shown in Fig. 1. In 1H NMR
spectrum of 5 the signals of CH2Te, middle CH2 and
NꢀCH2 appear deshielded (ꢀ0.80, 0.46 and 0.14 ppm,
respectively) with respect to those of L2, indicating in 5
ligation of L2 is as a (Te, N) donor, which is corrobo-
rated by deshielding of C6, C7 and C8 signals (ꢀ20, 7.5
and 8 ppm, respectively) in 13C NMR spectrum of 5,
with respect to those of free L2. The crystals suitable for
X-ray diffraction (XRD) could not be grown for 1–5.
3.1. Spectral data
IR spectrum of L1 has bands at 1641 and 3384 cm−1
due to CO and NH vibrations, respectively. The band
appearing at 441 cm−1 [TeꢀC (aliphatic) vibrations] in
IR of L1 shifts to ꢀ419 cm−1 on the formation of
1–4, indicating that L1 coordinates through Te. In IR
spectra of 1–4, NH band also shows a red shift of ꢀ30
cm−1 with respect to that of free ligand L1, suggesting
3.2. Crystal structures of L1 and L2
The molecular structure of L1 is shown in Fig. 2. The
selected bond lengths and angles are given in Table 2.
,
The TeꢀC(1) (2.107(8) A) is shorter than TeꢀC(8)
,
(2.140(8) A), as is generally reported [18–20] for
TeꢀC(aryl) in comparison to TeꢀC(alkyl). The

672
A.K. Singh et al. / Polyhedron 21 (2002) 667–674
Fig. 1. HETCOR spectrum of L2.
O(2B)ꢀC(11)ꢀN(1), O(2B)ꢀC(11)ꢀC(12), and N(1)ꢀ
C(11)ꢀC(12) is 356.7° compared with the sum for the
corresponding angles around C(18) of 360.1°, as ex-
pected for planar sp2 carbon. In L2H2, the
C(1)ꢀTeꢀC(8) angle (98.8(3)°) is consistent with the
literature reports on alkyl aryl tellurides [18–20]. The
CꢀC bond lengths and CꢀCꢀC bond angles of aryl
,
groups are normal (average values 1.372(4)–1.377(4) A
,
C(11)ꢀO(2A)H bond length is 1.298(6) A as expected
and 119.96(1)°, respectively). The molecular structure
of L2 is shown in Fig. 3(a) and L2H2 in Fig. 3(b). The
selected bond lengths and angles for L2 are given in
Table 3. The TeꢀC(alkyl) bond length is longer than
TeꢀC(aryl) in this case also as observed for L1. The
C(1)ꢀTe(1)ꢀC(8) angle is 94.96(14)° and consistent with
the value observed for L1. The average CꢀC bond
lengths and CꢀCꢀC bond angles of substituted phenyl
Table 2
1
,
Selected bond lengths (A) and angles (°) for L
Bond lengths
TeꢀC(1)
2.107(8)
1.369(9)
1.215(9)
1.507(10)
1.451(10)
TeꢀC(8)
2.140(8)
O(1)ꢀC(4)
O(2)ꢀC(10)
C(10)ꢀC(11)
NꢀC(9)
O(1)ꢀC(5)
NꢀC(10)
C(8)ꢀC(9)
1.416(13)
1.345(10)
1.490(12)
,
groups are normal (1.384(1) A and 120.0(1)°). The
defining features for the two molecules L2 and L2H2
present in the mixed crystal [‘L2’] are the angles about
C(11) and the C(11)ꢀO(2) bond distances. In spite of
the site mixing at C(11)ꢀO(2), resulting from the use of
a co-crystal, the geometric parameters for C(11)ꢀO(2)
as a carbonyl in the L2 compound are in very good
agreement with expected values. Thus, in L2 the
Bond angles
C(1)ꢀTeꢀC(8)
C(10)ꢀNꢀC(9)
C(2)ꢀC(1)ꢀTe
O(1)ꢀC(4)ꢀC(3)
NꢀC(9)ꢀC(8)
O(2)ꢀC(10)ꢀC(11)
98.8(3)
122.1(8)
118.2(6)
116.1(8)
111.4(8)
121.0(7)
C(4)ꢀO(1)ꢀC(5)
C(6)ꢀC(4)ꢀO(1)
C(7)ꢀC(1)ꢀTe
C(9)ꢀC(8)ꢀTe
O(2)ꢀC(10)ꢀN
NꢀC(10)ꢀC(11)
118.9(8)
124.4(8)
123.5(6)
114.0(7)
124.4(7)
114.7(7)
,
C(11)ꢂO(2B) bond length is 1.221(4) A compared with
C(16)ꢀC(11)ꢀC(10) 118.2(8)
C(12)ꢀC(11)ꢀC(10) 123.5(7)
,
1.223(4) A for C(18)ꢂO(3) and the sum of the angles

A.K. Singh et al. / Polyhedron 21 (2002) 667–674
673
Table 3
2
,
Selected bond lengths (A) and angles (°) for L
Bond lengths
Te(1)ꢀC(1)
O(1)ꢀC(4)
O(3)ꢀC(18)
N(1)ꢀC(10
C(8)ꢀC(9)
C(11)ꢀC(12)
C(12)ꢀC(13)
C(14)ꢀC(15)
C(16)ꢀC(17)
C(17)ꢀC(18)
Te(1)ꢀO(3)
2.123(4)
1.367(5)
1.223(4)
1.469(4)
1.521(5)
1.504(6)
1.381(5)
1.402(6)
1.373(5)
1.479(5)
3.700(4)
Te(1)ꢀC(8)
O(1)ꢀC(7)
2.149(4)
1.425(4)
1.221(4)
1.372(4)
1.442(5)
1.499(5)
1.386(5)
1.390(5)
1.378(5)
O(2B)ꢀC(11)
N(1)ꢀC(18)
N(1)ꢀC(11)
C(9)ꢀC(10)
C(12)ꢀC(17)
C(13)ꢀC(14)
C(15)ꢀC(16)
Te(1)ꢀO(2B)
6.321(4)
Bond angles
C(1)ꢀTe(1)ꢀC(8)
C(2)ꢀC(1)ꢀTe(1)
O(1)ꢀC(4)ꢀC(3)
C(9)ꢀC(8)ꢀTe(1)
O(2B)ꢀC(11)ꢀN(1) 131.0(5)
O(3)ꢀC(18)ꢀN(1) 125.3(4)
C(18)ꢀN(1)ꢀC(10) 122.8(3)
C(11)ꢀN(1)ꢀC(10) 123.4(3)
N(1)ꢀC(11)ꢀC(12) 102.3(3)
C(17)ꢀC(12)ꢀC(13) 120.3(4)
C(17)ꢀC(12)ꢀC(11) 109.7(4)
C(13)ꢀC(12)ꢀC(11) 129.9(4)
C(12)ꢀC(13)ꢀC(14) 118.5(4)
C(13)ꢀC(14)ꢀC(15) 120.2(4)
94.96(14) C(4)ꢀO(1)ꢀC(7)
117.7(3)
121.1(3)
124.4(4)
113.5(3)
120.3(3)
115.5(4)
114.1(3)
C(6)ꢀC(1)ꢀTe(1)
O(1)ꢀC(4)ꢀC(5)
C(10)ꢀC(9)ꢀC(8)
O(2B)ꢀC(11)ꢀC(12) 123.1(5)
O(3)ꢀC(18)ꢀC(17)
C(18)ꢀN(1)ꢀC(11)
N(1)ꢀC(10)ꢀC(9)
N(1)ꢀC(18)ꢀC(17)
C(16)ꢀC(15)ꢀC(14) 121.0(4)
C(17)ꢀC(16)ꢀC(15) 118.0(4)
C(16)ꢀC(17)ꢀC(12) 122.0(4)
C(16)ꢀC(17)ꢀC(18) 129.9(4)
C(12)ꢀC(17)ꢀC(18) 108.1(4)
128.5(4)
113.6(3)
113.4(3)
106.3(3)
In L2H2, O(2A)ꢀC(11) 1.298(6) A, O(2A)ꢀC(11)ꢀN(1) 114.7(4)°,
O(2A)ꢀC(11)ꢀC(12) 121.8(5)°.
,
Fig. 2. Molecular structure of L1.
Fig. 3. (a) Molecular structure of L2. (b) Molecular structure of L2H2.
for a CꢀO single bond, and the sum of the angles
O(2A)ꢀC(11)ꢀN(1), O(2A)ꢀC(11)ꢀC(12), and N(1)ꢀ
C(11)ꢀC(12) is 338.8°, consistent with tetrahedral sp3
carbon. The possibility of coordinating as a (Te, N)
donor is apparent for L1 and L2 (Figs. 2 and 3). They
may also act as a (Te, N, O) donor in bimetallic
complexes.
4. Conclusion
Two new hybrid organotellurium ligands N-[2-(4-
methoxyphenyltelluro)ethyl]benzamide (L1) and N-[2-
(4-methoxyphenyltelluro)propyl]phthalimide(L2) have
been synthesized and characterized structurally. The

674
A.K. Singh et al. / Polyhedron 21 (2002) 667–674
Liaw, G.H. Lee, S.M. Peng, Inorg. Chem. 34 (1995) 3755 and
,
TeꢀC(alkyl) bond length is 2.140(8)/2.149(4) A and
longer than TeꢀC(aryl) 2.107(8)/2.123(5) A. Both of
them coordinate as a (Te, N) donor with Pd(II), Pt(II)
or Ru(II).
references therein.
[6] (a) W. Levason, S.D. Orchard, G. Reid, Organometallics 18
(1999) 1275;
,
(b) W. Levason, S.D. Orchard, G. Reid, J. Chem. Soc., Dalton
Trans. (1999) 823;
(c) J.R. Black, N.R. Champness, W. Levason, G. Reid, Inorg.
Chem. 35 (1996) 1820;
(d) W. Levason, S.D. Orchard, G. Reid, V.-A. Tolhurst, J.
Chem. Soc., Dalton Trans. (1999) 2071.
5. Supplementary material
[7] (a) M. Misra, A.K. Singh, Phosphorus Sulfur Silicon 134/135
(1998) 537;
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC 151396 for L1 and 151397 for L2.
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 www: http://
www.ccdc.cam.ac.uk).
(b) M. Misra, A.K. Singh, J. Coord. Chem. 48 (1999) 43;
(c) A.K. Singh, C.V. Amburose, M. Misra, R.J. Butcher, J.
Chem. Res. (S) (1999) 716.
[8] (a) A.K. Singh, V. Srivastava, Phosphorus Sulfur Silicon 47
(1990) 471;
(b) A.K. Singh, V. Srivastava, B.L. Khandelwal, Polyhedron 9
(1990) 495;
(c) V. Srivastava, R. Batheja, A.K. Singh, J. Organomet. Chem.
484 (1994) 93.
[9] (a) V.K. Jain, S. Chaudhury, R. Bohra, Polyhedron 12 (1993)
2377;
Acknowledgements
(b) A.K. Singh, V. Srivastava, J. Coord. Chem. 21 (1990) 39;
(c) A.K. Singh, J. Sooriyakumar, S. Husebye, K.W. Tornroos, J.
Organomet. Chem. 612 (2000) 46.
J.E. Drake wishes to thank the Natural Sciences and
Engineering Research Council, Canada. Ajai K. Singh,
J. Sooriyakumar and M. Kadarkaraisamy thank De-
partment of Science and Technology (India) for finan-
cial support.
[10] A. Khalid, A.K. Singh, Polyhedron 16 (1997) 33.
[11] (a) K.D. Hodges, J.V. Rund, Inorg. Chem. 14 (1975) 525;
(b) T.B. Rauchfuff, J.S. Shu, D.M. Roundhill, Inorg. Chem. 15
(1976) 2096.
[12] (a) G.M. Sheldrick, SHELXA: Program for Empirical Absorption
Correction, University of Go¨ttingen, Go¨ttingen, Germany, 1993;
(b) G.M. Sheldrick, SHELXA: Program for Refinement of Crystal
Structure, University of Go¨ttingen, Go¨ttingen, Germany, 1993;
(c) G.M. Sheldrick, SHELXA: Program for Solution of Crystal
Structure, University of Go¨ttingen, Go¨ttingen, Germany, 1986.
[13] Denzo (Z. Otwinowski, W. Minor, Methods in enzymology, in:
C.W. Carter Jr., R.M. Sweet, (Eds.), Macromolecular Crystal-
lography, Part A, vol. 276, Academic Press, 1997 pp. 307).
[14] SORTAV (R.H. Blessing, Acta Crystallogr. A51 (1995) 33; R.H.
Blessing, J. Appl. Cryst. 30 (1997) 421.
[15] G.M. Sheldrick, Acta Crystallogr. A46 (1990) 467.
[16] G.M. Sheldrick, SHELXL97, University of Go¨ttingen, Germany,
1997.
[17] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.
[18] J.E. Drake, J. Yang, A. Khalid, V. Srivastava, A.K. Singh,
Inorg. Chim. Acta 254 (1997) 57.
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B. Varghese, R.J. Butcher, J. Organomet. Chem. 605 (2000) 39;
(d) A.K. Singh, J. Sooriyakumar, M. Kadarkaraisamy J.E.
Drake, M.B.Hursthouse, M.E. Light, R.J. Butcher, J. Chem.
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[19] J.E. Drake, J.H.E. Bailey, A.K. Singh, V. Srivastava, Acta
Crystallogr. C49 (1993) 684.
[20] A.K. Singh, V. Srivastava, S.K. Dhingra, J.E. Drake, J.H.E.
Bailey, Acta Crystallogr. C48 (1992) 655.
[5] W.F. Liaw, C.H. Lai, S.J. Chiou, Y.C. Horng, C.C. Chou, M.C.