First example of bimetallic complex of platinum(II) with a hybrid organotellurium ligand [(4-MeOC6H4Te)CH2CH 2OCH2CH2CH2 (2-C5H 4N)] (L1) contain

Article abstract of DOI:10.1016/j.inoche.2003.08.020

1-(4-Methoxyphenyltelluro)-2-[3-(6 methyl-2 pyridyl)propoxy]ethane (L ¹) and its complexes [MCl₂(L¹)]₂ (M = Pd or Pt) have been synthesized. The single crystal X-ray diffraction of [PtCl₂(L¹

Full text of DOI:10.1016/j.inoche.2003.08.020

Inorganic Chemistry Communications 6 (2003) 1378–1381
www.elsevier.com/locate/inoche
First example of bimetallic complex of platinum(II) with a hybrid
organotellurium ligand [(4-MeOC H Te)CH CH OCH CH CH
6
4
2
2
2
2
2
1
(
2-C H N)] (L ) containing 20-membered metallomacrocycle
5
4
ring: synthesis and crystal structure
a
a,
a
b
Sumit Bali , Ajai K. Singh , Pankaj Sharma , J.E. Drake ,
*
c
M.B. Hursthouse , M.E. Light
c
a
Department of Chemistry, Indian Institute of Technology, New Delhi 110016, India
b
Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ont., Canada N9B 3P4
c
Department of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
Received 5 June 2003; accepted 28 August 2003
Published online: 25 September 2003
Abstract
1
1
1
-(4-Methoxyphenyltelluro)-2-[3-(6 methyl-2 pyridyl)propoxy]ethane (L ) and its complexes [MCl2(L )]2 (M ¼ Pd or Pt) have
1
been synthesized. The single crystal X-ray diffraction of [PtCl2(L )]2 Æ 2CHCl3 shows a bimetallic complex of platinum(II) containing
a 20-membered metallomacrocycle ring, which remains stable in solution as shown by molecular weight and conductance mea-
ꢀ
surements. The Pt–Te and Pt–N bond lengths are 2.5409(3) and 2.087(5) A, respectively. The protons of CH2 linked to Te show a
deshielding > 1 ppm on the formation of the two complexes.
Ó 2003 Elsevier B.V. All rights reserved.
Keywords: Platinum; Complex; 1-(4-Methoxyphenyltelluro)-2-[3-(6 methyl-2 pyridyl)propoxy]-ethane; Hybrid organotellurium ligand; Crystal
structure; Synthesis
Mono and bi-nuclear metal complexes with nitrogen,
oxygen, sulfur and phosphorus ligands containing
large size chelate ring are not numerous[1–6]. The
complexes [Cu2(l-dppy)3(MeCN)][BF4]2 (where dppy ¼
bered chelate ring. Two well known examples of metal-
lomacrocycles containing telluroether ligands are the
polymeric silver(I) complex of MeTe(CH2)3TeMe [6a]
and the mononuclear Hg(II) complex of 1,6-bis-2-
butyltellurophenyl-2,5-diazahexa-1,5-diene [6b] with
24- and 13-membered rings, respectively. No example
containing a macrocycle formed by a hybrid organotel-
lurium ligand has been reported so far for platinum(II).
Our interest in (Te , N ) type hybrid organotellurium
2
-(diphenylphosphino)pyridine), trans-[1,8-bis(diphenyl-
0
phosphino)-3,6-dioxaoctane-P,P ]
rhodium(I) hexaflurophosphate [2], trans-[1,5-bis(diph-
carbonyl(ethanol)
0
enylphosphino)-3-oxapentane-P,P ]carbonylchlororho-
dium(I) dimer [2] di-l-[glutaraldehydebis(dimethyl-
hydrazone)]-bis[dichloropalladium(II)] [3] [{CoCl2Ph2
CH2CH2P(O)Ph2}2][4] and dinuclear platinum(II)
complex of the dithioether ligand 1,5-bis(n-propylthio)-
pentane [5] are some examples containing 8 to 16-mem-
x
y
ligands [7a] has led us to explore macrocycle containing
tellurium and nitrogen donor atoms and we have de-
signed a 20-membered metallomacrocycle ring using the
hybrid organotellurium ligand 1-(4-methoxyphenyltell-
1
uro)-2-[3-(6-methyl-2-pyridyl)propoxy] ethane (L ) and
platinum(II) for the first time. Palladium(II) complex of
*
Corresponding author. Tel.: +11-26591379; fax: +11-6581037.
E-mail addresses: aksingh@chemistry.iitd.ac.in, ajai57@hotmail.
com (A.K. Singh).
1
L appears to be a similar metallomacrocycle. Recently,
a Pd(II) complex of a macrocyclic ligand having Te and
1
387-7003/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2003.08.020

S. Bali et al. / Inorganic Chemistry Communications 6 (2003) 1378–1381
1379
1
N donor sites has been characterized structurally but the
ligand breaks on complexation with Pt(II) [7b].
conditions. Ligand L and its two complexes are au-
1
thenticated [18–20] by elemental analyses, H (and
13
1
1
1
The ligand L (viscous oil) synthesized by the reac-
tions given in Scheme 1 remains stable under ambient
C{ H} also in the case of 1) NMR spectra. The H
NMR spectra of the complexes 1 (single crystals) and 2
were found to be similar and somewhat complex in the
alkyl region, indicating that the two complexes have
structural similarity. In the spectrum of 1 the two sing-
lets at 7.26–7.28 are due to two chloroform molecules
identified in the lattice of its single crystal. The H1
proton in the spectrum of 1 appears maximum de-
shielded (ꢀ1.14–1.41 ppm) with respect to that of free
1
conditions for 3–4 months. The L , 1 and 2 have good
solubility in chloroform and dichloromethane. In
1
methanol and hexane the solubility of L was only
moderate. The reactions of L1 with K PtCl4 and
2
[(PhCN)2PdCl2] gave complexes having metal to ligand
ratio as 1:1 (Scheme 1), which are stable under ambient
1
L as it coordinates through Te. Similarly, deshielding
1
of H5 with respect to that of free L is also large (ꢀ0.85
ppm) because the ligand also coordinates via pyridine
nitrogen, which is also reflected in the deshielding of
H . All other CH protons also exhibit deshielding
1
1
2
(
(
0.1–0.3 ppm). Some of them become nonequivalent
viz. H1, H3 and H5) also. Pyridine and aryl protons also
appear deshielded (0.1–0.2 ppm). The rigidity in the
structure of the complex in comparison to that of free
ligand is probably responsible for the complexity ob-
served in the proton NMR of the complexes 1 and 2. On
1
3
1
comparing the C{ H} NMR spectrum of the Pt
1
complex with that of L it is apparent that the C signal
1
Scheme 1.
undergoes highest deshielding (ꢀ10 ppm), which con-
curs with the proton NMR spectrum. For all other
carbon signals the deshielding is less than 4.0 ppm. In
Table 1
Crystal data and structure refinement for [PtCl2L]2 Æ 2CHCl3
the IR spectrum of the Pt-complex the bands at 331 and
ꢁ1
346 cm may be assigned to symmetric and asymmetric
stretching of the trans Cl–Pt–Cl system [13], respectively.
Empirical formula
Formula weight
Temperature (K)
19 2 5
C H24NO Cl PtTe
798.33
120(2)
ꢀ
Wavelength (A)
0.71073
Triclinic
P-1
Crystal system [8]
Space group
ꢀ
a (A)
8.9977(1)
9.0841(2)
15.2134(3)
88.694(1)
84.896(1)
81.391(2)
1224.54(4)
2
ꢀ
b (A)
ꢀ
c (A)
a (°)
b (°)
c (°)
ꢀ
3
Volume (A)
Z
3
Density (calculated) (g/cm )
Absorption coefficient (mm
F(000)
2.165
7.459
ꢁ
1
)
752
0.20 ꢂ 0.15 ꢂ 0.15
3
Crystal size (mm )
h range for data collection (°)
Index ranges
2.98–27.48
)10 6 h 6 11, )11 6 k 6 11,
)
18001
19 6 l 6 19
Reflections collected
Independent reflections
Max. and min. transmission
Refinement method
5502 [Rint ¼ 0:0513]
0.4008 and 0.3170
Full-matrix least-squares on
2
F
Data/restraints/parameters
2
5502/0/264
1.057
Goodness-of-fit on F
2
2
Final R indices [F > 4rðF Þ]
R indices (all data)
Largest diff. peak and hole
R
R
1
¼ 0:0383, wR
2
2
¼ 0:0977
¼ 0:1000
1
¼ 0:0411, wR
1
Fig. 1. ORTEP plot of the molecule [PtCl2L ] ꢃ 2CHCl3. The atoms are
2.160 and )5.019
ꢁ
3
drawn with 50% probability ellipsoids. The CHCl molecule and all the
3
ꢀ
e A )
(
H atoms are omitted for clarity.

1380
S. Bali et al. / Inorganic Chemistry Communications 6 (2003) 1378–1381
The band at 480 cm 1 may be assigned to Te–C(alkyl)
vibrations [14].
ꢁ
osmometrically) and conductance values. Platinum has
square planar geometry with two Cl (trans to each
other), Te and N atoms constituting its coordination
X-ray diffraction data were collected on an Enraf
Nonius Kappa CCD area detector diffractometer at 120
K with / and x scans chosen to give a complete
asymmetric unit. An absorption correction was applied
9]. The structure was solved by the use of the program
DIRDIFF-99 [10] and refined using the WinGX version
11] of SHELXL-97 [12]. Crystallographic data are given
with in Table 1. The molecule [PtCl2L ]2 Æ 2CHCl3 is
shown in Fig. 1 and selected bond distances and bond
angles are given in Table 2. Additional material is
available from the Cambridge Crystallographic Data
Centre (CCDC number 212111). This is the first exam-
ple of the formation of a 20-membered metallomacro-
cycle ring by a hybrid organotellurium ligand. The
bimetallic Pt complex also remains dimeric in solution
as confirmed [19] by molecular weight (determined
ꢀ
sphere. The Pt–Cl bond lengths 2.319(1)/2.293(1) A are
ꢀ
consistent with the earlier reports of 2.297 (2) A for a
trans Cl–Pt–Cl system [15]. The Te–C(aryl) bond is
shorter than that of Te–C(alkyl) as reported earlier [16].
ꢀ
The Pt–Te bond length of 2.5409(3) A in the present
complex is somewhat shorter than the Pt–Te bond
ꢀ
length 2.583(2) A observed for Pt complexes of
monodentate tellurides [15]. By contrast, the Pt(1)–N(1)
[
[
1
ꢀ
bond length of 2.087(5) A is a little longer than the
ꢀ
ꢀ
literature values 2.005(17) A [16] and 2.05(1) A [17],
probably due to the trans influence of Te. However,
crystal of 2 does not diffract and consequently
1
structure of Pd-complex of L could not be confirmed.
The molecular weight of 2 indicates its dimeric nature
[20].
Table 2
ꢀ
a
Bond lengths [A] and angles [°] for [PtCl2L]2 Æ 2CHCl3
Pt(1)–Cl(1)
Pt(1)–Te(1)
Pt(1)–Cl(1)
Te(1)–C(1)
O(1)–C(4)
2.293(1)
2.5409(3)
2.293(1)
2.135(5)
1.366(6)
1.437(7)
1.335(7)
1.379(7)
1.405(7)
1.394(8)
1.518(7)
1.534(7)
1.406(7)
1.487(7)
1.368(8)
1.759(6)
1.758(5)
177.67(4)
94.98(3)
86.7(1)
Pt(1)–Cl(2)
0
2.319(1)
2.087(5)
2.319(1)
2.156(5)
1.413(6)
1.441(6)
1.355(6)
1.394(7)
1.391(7)
1.383(7)
1.519(7)
1.517(7)
1.397(7)
1.380(7)
Pt(1)–N(1)
Pt(1)–Cl(2)
Te(1)–C(8)
O(2)–C(9)
O(1)–C(7)
O(2)–C(10)
N(1)–C(14)
C(1)–C(2)
N(1)–C(13)
C(1)–C(6)
C(2)–C(3)
C(3)–C(4)
C(5)–C(6)
C(4)–C(5)
C(8)–C(9)
C(10)–C(11)
C(12)–C(13)
C(14)–C(15)
C(15)–C(16)
C(11)–C(12)
C(13)–C(17)
C(14)–C(18)
C(16)–C(17)
Cl(3)–C(19)
Cl(5)–C(19)
Cl(1)–Pt(1)–Cl(2)
Cl(1)–Pt(1)–Te(1)
Cl(4)–C(19)
0
1.755(5)
2.087(5)
177.2(1)
87.34(3)
91.0.(1)
103.9(1)
120.3(5)
118.9(3)
118.3(4)
119.9(5)
120.2(5)
119.8(5)
115.2(5)
113.8(4)
108.4(4)
112.5(4)
119.7(4)
119.4(5)
119.0(4)
119.6(5)
119.4(5)
110.6(3)
N(1)–Pt(1)
Te(1)–Pt(1)–N(1)
Cl(2)-Pt(1)–Te(1)
0
0
0
Cl(1)–Pt(1)–N(1)
C(1)–Te(1)–Pt(1)
C(1)–Te(1)–C(8)
Cl(2)–Pt(1)–N(1)
C(8)–Te(1)-Pt(1)
C(13)–N(1)–C(14)
103.6(1)
98.8(2)
0
0
C(13)–N(1)–Pt(1)
C(2)–C(1)–Te(1)
C(6)–C(1)–C(2)
120.6(3)
121.0(4)
120.5(4)
119.1(5)
120.5(5)
124.6(5)
117.8(4)
112.4(3)
113.8(4)
109.4(4)
120.9(5)
120.3(5)
120.6(4)
119.4(5)
110.4(3)
110.3(3)
C(14)–N(1)–Pt(1)
C(6)–C(1)–Te(1)
C(1)–C(2)–C(3)
C(3)–C(4)–C(5)
C(2)–C(3)–C(4)
C(4)–C(5)–C(6)
C(1)–C(6)–C(5)
O(1)–C(4)–C(5)
O(1)–C(4)–C(3)
C(4)–O(1)–C(7)
C(9)–C(8)–Te(1)
O(2)–C(10)–C(11)
C(13)–C(12)–C(11)
N(1)–C(13)–C(17)
N(1)–C(14)–C(15)
C(15)–C(14)–C(18)
C(17)–C(16)–C(15)
Cl(3)–C(19)–Cl(4)
Cl(4)–C(19)–Cl(5)
C(9)–O(2)–C(10)
O(2)–C(9)–C(8)
C(10)–C(11)–C(12)
N(1)–C(13)–C(12)
C(17)–C(13)–C(12)
N(1)–C(14)–C(18)
C(14)–C(15)–C(16)
C(13)–C(17)–C(16)
Cl(3)–C(19)–Cl(5)
a
Symmetry position ðꢁx; ꢁy þ 2; ꢁz þ 1Þ given by a prime.

S. Bali et al. / Inorganic Chemistry Communications 6 (2003) 1378–1381
1381
Acknowledgements
[10] P.T. Beurskens, G. Beurskens, R. de Gelder, S. Garcia-Granda,
R. Israel, R.O. Gould, J.M.M. Smits, DIRDIFF-99, University of
Nijmegen, The Netherlands.
M.B.H. thanks the UK Engineering and Physical
Sciences Council for support of the X-ray facilities at
Southampton. J.E.D. thanks the Natural Sciences and
Engineering Research Council of Canada for financial
support. AKS and SB thank Department of Atomic
Energy (India) for financial support. P.S. is thankful to
DGAPA,UNAM for financing sabbatical stay at IITD.
[
[
11] L.J. Farrugia, J. Appl. Cryst. 32 (1999) 837.
12] G.M. Sheldrick, SHELXL-97, University of Gottingen, Germany.
[13] R. Romeo, M.L. Tobe, Inorg. Chem. 13 (1974) 1991.
[14] A. Khalid, A.K. Singh, Polyhedron 16 (1997) 33.
[
[
[
[
15] A.K. Singh, J. Soorikumar, R.J. Butcher, Inorg. Chim. Acta 312
2001) 163.
(
16] A. Khalid, B.L. Khandelwal, A.K. Singh, T.P. Singh, B. Padma-
nabhan, J. Coord. Chem. 31 (1994) 19.
17] J.E. Drake, J.H.E. Bailey, A.K. Singh, V. Srivastava, Acta Cryst.
C49 (1993) 684.
1
18] L (yellow viscous oil): Analyses: Found Te, 30.54%; Calc. for
I
References
C
18
H
23NO
2
Te, Te, 30.92%. Yield, 70%; H NMR (CDCl
3
, 25 °C): d
(
vs TMS): 1.91–2.01(m, 2H, H
4
), 2.52 (s, 3H, H11), 2.71–2.82 (t, 2H,
), 3.43–3.47 (t, 2H, H ), 3.66–3.70 (t, 2H,
), 6.73–6.76 (d, 2H, m to Te), 6.93–6.96 (d,
[
[
[
[
[
[
1] E. Lastra, M.P. Gamasa, J. Gimeno, M. Lanfranchi, A. Tiripic-
chio, J. Chem. Soc., Dalton Trans. (1989) 1499.
2] N.W. Alcock, J.M. Brown, J.C. Jeffery, J. Chem. Soc., Dalton
Trans. (1977) 888.
H
1
), 2.95–3.00 (t, 2H, H
), 3.78 (s, 3H, OCH
and H ), 7.43–7.48(t, 1H, H
{ H} NMR (CDCl
28.91(C
114.83 (C
(ArC o to Te), 157.35 (C10), 160.52 ( ArC p to Te), 161.15 (C
[19] Complex 1: m.p. (in open capillary) 126 °C; mol. wt. (microcrys-
5
3
H
2
3
13
2H, H
1
7
9
8
), 7.65–7.70(d, 2H, o to Te); C
3
1
, 25 °C): d (vs TMS): 8.16 (C ), 24.14 (C11),
3] A.G. Constable, W.S. McDonald, B.L. Shaw, J. Chem. Soc.,
Dalton Trans. (1979) 1109.
4
), 54.78 (OCH
3
), 69.48 (C
2
), 71.85 (C
3
), 99.81(ArTe–C),
), 140.62
).
9
), 119.37 (ArC m to Te), 120.19 (C
7
), 136.44 (C
8
4] S.I. Al-Resayes, P.B. Hitchcock, J.F. Nixon, J. Chem. Soc. Chem.
Commun. (1991) 78.
6
ꢁ
1
2
5] J.R. Li, M. Du, R.H. Zhang, X.H. Bu, J. Mol. Struct. 607 (2002)
talline sample): Found: 1324. 2; Calc.: 1357.3 K
M
, 10.54 ohm cm
mol . Analyses (microcrystalline sample): FoundC, 32.91; H, 3.80;
N, 2.00; Te, 18.92 %. Calc. for [C18 NTePtCl : C, 31.82; H,
3.38; N, 2.06; Te, 18.80 %. NMR of single crystals: H (CDCl
°C): d (vs TMS): 2.22–2.30 (m, 2H, H
), 3.55–3.67 (m, 2H, H + H ), 3.81–3.84 (m, 4H, CH
3.90–3.92 (t, 2H, H ), 4.12–4.14 (m, 1H, H
6.87–6.94 (m, 2H, m to Te), 7.10–7.13 (m, 2H, H
(bs, 2H, CHCl ), 7.53–7.61 (m, 1H, H ), 7.80–7.83 (d, 1H, ArH o to
Te), 8.00–8.06(m, 1H ArHoto Te); C{ H}-NMR(CDCl
(vs TMS): 18.90 (C ), 26.84 (C11), 28.08 (C ), 55.30 (OCH
(C ), 70.63 (C ), 99.81 (ArTe-C), 115.21 (C ), 122.70 (ArC m to Te),
123.88 (C ), 138.49 (C ), 140.60 (ArC o to Te), 160.00 (C10), 160.62
(ArC p to Te), 161.20 (C ).
ꢁ1
175.
6] (a) W.F. Liaw, C.H. Li, S.J. Chio, Y.C. Horng, C.C. Chou,
M.C. Liaw, G.H. Lee, S.M. Peng, Inorg. Chem. 34 (1995)
H
23
O
2
2 2
]
I
3
, 25
3755;
4
), 3.26–3.32 (m, 4H, H11
+
),
),
(b) N. Al-Salim, T.A. Hamor, W.R. McWhinnie, J. Chem. Soc.
Chem. Commun. (1986) 453.
H
3
5
3
3
O + H
5
1
2
1
), 4.26–4.41 (m, 1H, H
and H
[
7] (a) N.I. Al-Salim, W.R. McWhinnie, Polyhedron 8 (1989) 2769;
A.K. Singh, V. Srivastava, Phosphorus Sulfur Silicon 47
7
9
), 7.26–7.28
3
8
13
1
(1990) 471;
J. Coord. Chem. 21 (1990) 39;
3
, 25°C: d
), 66.91
1
4
3
A.K. Singh, V. Srivastava, B.L. Khandelwal, Polyhedron 9
2
3
9
(
1990) 495, see also p. 851;
V. Srivastava, R. Batheja, A.K. Singh, J. Organomet. Chem.
84 (1994) 93;
A.K. Singh, S. Sharma, Coord. Chem. Rev. 209 (2000)
9;
7
8
6
4
[20] Complex 2: m.p.(in open capillary) 125 °C(d) ; Mol. wt (microcrys-
talline sample): Found: 1144.6; Calc.: 1180. Analyses (microcrys-
talline sample): Found C, 36.24; H, 3.89; N, 2.31%. Calc. for
4
(
b) S.C. Menon, A. Panda, H.B. Singh, R.J. Butcher, J. Chem.
Soc. Chem. Commun. (2000) 143.
23 2 2 2
[C18H O NTePdCl ] : C, 36.60; H, 3.97; N, 2.37%. NMR (micro-
I
crystalline sample): H (CDCl
3
, 25 °C): d (vs TMS): 2.28 (bm, 2H,
), 3.30–3.31 (s, 3H, H11) 3.59–3.66 (m, 3H,
), 3.81–3.83(m, 4H, CH O), 3.86–3.95(t, 2H, H ), 4.12–4.26
), 4.41 (m, 1H, H ), 6.87–6.94 (m, 2H, m to Te), 7.10–7.12
and H ), 7.47–7.61 (m, 1H, H ), 7.80–7.83 (d, 1H, ArH o
to Te), 8.00–8.06 (m, 1H ArH o to Te).
[
[
8] DENZO Z. Otwinowski, W. Minor, in: C.W. Carter Jr., R.M.
Sweet (Eds.), Methods in Enzymology, Macromolecular Crystal-
lography, Part A, vol. 276, Academic Press, 1997, p. 307.
9] SORTAV R.H. Blessing, Acta Cryst. A 51 (1995) 33;
R.H. Blessing, J. Appl. Cryst. 30 (1997) 421.
H
H
4
5
), 3.23–3.26 (m, 1H, H
+ H
3
3
3
2
(m, 1H, H
(m, 2H, H
1
1
7
9
8