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Polyhedron 19 (2000) 2689 – 2695
Synthesis, spectral properties, crystal structures and antimicrobial
effects of copper(II) pyridinecarboxylate adducts with chelating
ligands
Martina Palicova ´
a,
*, Peter Segl’a
a
, Dus ˇan Miklos ˇ
a
, Miroslava Kopcova ´
a
,
Milan Melnı ´k
a
, Barbora Dudova ´
b
, Daniela Hudecova ´
b
, Tadeusz Glowiak
c
a
Department of Inorganic Chemistry, Sloak Technical Uniersity, 812 37 Bratislaa, Sloak Republic
b
Department of Biochemistry and Microbiology, Sloak Technical Uniersity, 812 37 Bratislaa, Sloak Republic
c
Institute of Chemistry, Uniersity of Wroclaw, F. Joliot -Curie 14, 50 383 Wroclaw, Poland
Received 27 July 2000; accepted 8 September 2000
Abstract
The reaction of an ethanolic solution of copper(II) pyridinecarboxylates CuX
2
·n H
2
O (where X is nicotinate (nic) (n =0) or
isonicotinate (isonic) (n =4)) with ethylenediamine (en) in a molar ratio of 1:2 lead to the isolation of solid tetragonally distorted
octahedral complexes of the type [Cu(en)
2
(H
2
O)
2
]X
2
·n H
2
O(n =1 for nic; n =0 for isonic). The analogous reaction of CuX
2
·n H
2
O
with diethylenetriamine (dien) in a molar ratio of 1:1 leads to the formation of square-pyramidal pentacoordinated complexes of
the type [CuX(dien)(H
2
O)]X. On the other hand, the reaction of equimolar quantities of copper(II) nitrate and dien with
nicotinate anions (equimolar quantities of pyridinecarboxylic acid and NaOH) in ethanolic solutions gives a solid monomeric
complex [Cu(nic)(NO
3
)dien)(H
2
O)]·H
2
O in which the coordination polyhedron around the Cu(II) atom is a (4 +1 +1) distorted
tetragonal bipyramid. Based on the molecular structure the electronic and IR spectra are discussed. Moreover, the results of the
quantitative determination of antimicrobial activity of the isonic complexes [Cu(isonic)
2
(H
2
O)
4
], [Cu(en)
2
(H
2
O)
2
](isonic)
2
,
[Cu(isonic)(dien)(H
2
O)](isonic), as well as isonicotinic acid, ethylenediamine and diethylenetriamine alone are discussed. © 2000
Elsevier Science B.V. All rights reserved.
Keywords: Chelating ligands; Crystal structures; Copper(II) complexes; Pyridinecarboxylate complexes; Antimicrobial activity
1. Introduction
Carboxylatocopper(II) complexes are interesting
from both a chemical and 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. Pyridinecarboxylic acid
and its derivatives possessing very interesting pharma-
ceutical properties constitute an important group of
anthelmintics and vitamins. It is known that some
drugs act via chelation [1] or via inhibition of metal-
loenzymes [2], but little is known about the modifica-
tion of activity of most drugs when their ligating
potential is utilized.
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 [3,4].
Only a few structures of [CuX
2
(H
2
O)
4
] [5] and their
adducts with chelating ligands 1,10-phenanthroline and
2,2-bipyridine have been reported [6,7]. Different coor-
dination modes of the pyridinecarboxylate (coordinated
not only through the carboxylate group, but also
through the nitrogen atom of the pyridine ring) lead to
formation of mononuclear [5] or polynuclear [6,7] struc-
tures. Recently, we have studied [8] the adducts of
Cu(II) isonicotinate with ethylenediamine (en) and di-
ethylenetriamine (dien), prepared [Cu(en)
2
(H
2
O)
2
]-
(isonic)
2
and [Cu(isonic)(dien)(H
2
O)
1.5
]·0.5SO
4
·2.5H
2
O
and solved their structures by X-ray analysis.
* Corresponding author. Tel.: +421-7-593-25611; fax: +421-7-
524-93198.
E-mail address: palicova@chtf.stuba.sk (M. Palicova ´).
0277-5387/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved.
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