Polyhedron 20 (2001) 1867 – 1874
Synthesis, spectral and magnetic properties, and crystal structures
of copper(II)2-methylthionicotinate adducts with chelating ligands
Dus ˇan Miklos ˇ
a,
*, Peter Segl’a
a
, Martina Palicova ´
a
, Miroslava Kopcova ´
a
,
Milan Melnı ´k
a
, Marian Valko
b
, Tadeusz Glowiak
c
, Maria Korabik
c
,
Jerzy Mrozinski
c
a
Department of Inorganic Chemistry, Sloak Technical Uniersity, 812 37 Bratislaa, Sloak Republic
b
Department of Physical Chemistry, Sloak Technical Uniersity, 812 37 Bratislaa, Sloak Republic
c
Faculty of Chemistry, Uniersity of Wroclaw, F. Joliot Curie 14, 50 383 Wroclaw, Poland
Received 4 January 2001; accepted 21 February 2001
Abstract
The synthesis and characterization of [Cu
2
(2-MeSnic)
4
(H
2
O)
2
], [Cu(2-MeSnic)
2
(en)], [Cu(en)
2
(H
2
O)
2
](2-MeSnic)
2
and [Cu-
(dien)(H
2
O)
2
](2-MeSnic)
2
(where 2-MeSnic =2-methylthionicotinate, en =ethylenediamine, dien =diethylenetriamine) is reported.
The characterizations were based on elemental analysis, infrared, electronic and EPR spectra, and magnetic susceptibility
measurements over a temperature range of 1.9 – 300 K. The available evidence supports a dimeric structure for [Cu
2
(2-
MeSnic)
4
(H
2
O)
2
] and for [Cu(en)
2
(H
2
O)
2
](2-MeSnic)
2
a tetragonal-bipyramidal environment about the copper(II) atom. The other
two complexes were studied also by X-ray analysis. The [Cu(dien)(H
2
O)
2
](2-MeSnic)
2
crystallizes in the monoclinic system. The
copper(II) atom has a square-pyramidal arrangement, with three nitrogen atoms of the tridentate diethylenetriamine and one
water molecule in the base of the pyramid, and the remaining water molecule occupies the apical position. The copper(II) atom
deviates from the basal plane by 0.1164(5) A toward the water molecule in the apical position. The copper(II) atom in
[Cu(2-MeSnic)
2
(en)] is coordinated by two symmetry-dependent nitrogen atoms of ethylenediamine and by two pairs of
non-equivalently coordinated carboxyl oxygen atoms of two symmetry-dependent 2-methylthionicotinates with CuO bond
distances of 1.975(2) and 2.564(2) A , respectively, resulting in a highly distorted tetragonal-bipyramidal coordination. © 2001
Elsevier Science Ltd. All rights reserved.
Keywords: Chelating ligands; Crystal structures; Copper(II) complexes; Pyridinecarboxylate complexes; Dimeric complexes
www.elsevier.com/locate/poly
1. Introduction
Nicotinic acid and its derivatives possess very inter-
esting pharmaceutical properties and are important
from a biological point of view. Different possible
coordinations of the carboxyl group to the central atom
lead to the existence of compounds with distinct crystal
structures.
Synthesis, spectral and thermal properties of various
complexes CuX
2
·n H
2
O (where X is pyridine-3-carboxy-
late or nicotinate (nic) and pyridine-4-carboxylate or
isonicotinate (isonic; n =0–4) have been reported [1,2].
Only a few structures of [CuX
2
(H
2
O)
4
] [3] and their
adducts with chelating ligands 1,10-phenanthroline,
2,2-bipyridine, ethylenediamine (en) and diethylenetri-
amine (dien) have been reported [4–7]. For example,
the reaction of ethanolic solution of copper(II)
pyridinecarboxylates CuX
2
·n H
2
O (where X is nic or
isonic, n =0 and 4, respectively) with en in a molar
ratio of 1:2 leads to isolation of solid complexes of the
type [Cu(en)
2
(H
2
O)
2
]X
2
·n H
2
O(n =1 and 0), which con-
tain uncoordinated pyridinecarboxylate anions and
with dien in a molar ratio of 1:1, leads to the formation
of pentacoordinated complexes of the type [CuX(-
dien)(H
2
O)]X (X =nic or isonic), which contain coordi-
nated and uncoordinated pyridinecarboxylate anions
[6,7]. Also, the different coordination modes of the
pyridinecarboxylate (coordinated not only through the
* Corresponding author. Tel.: +421-7-59325614; fax: +421-7-
52493198.
E-mail address: miklos@cvt.stuba.sk (D. Miklos ˇ).
0277-5387/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
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