Abstract
A series of unsymmetrical diorganotin derivatives of
quinoline-2-carboxylic acid (LH), namely polymeric \MePhSnClL\n (1)
and \EtPhSnClL\n (2), and mononuclear MePhSnL2 (3) and EtPhSnL2 (4),
was synthesized by the reaction of LH with the MePhSnCl2, EtPhSnCl2,
MePhSnO, and EtPhSnO precursors, respectively. The compounds were
characterized by elemental analysis and infrared spectroscopy, as well
as by 1?H, 13?C and 119Sn NMR. The molecular structures of
representative compounds 2 and 4 were determined by single-crystal X-ray
crystallography. This study showed that polymeric 2 adopts a distorted
octahedral geometry as the carboxylate ligand N,O chelates an Sn atom
and at the same time bridges a neighbouring Sn atom via the second O
atom, with the remaining sites being occupied by the Cl and two C atoms;
the O atoms are trans to each other. The result of the mu 2-bridging
mode of L- is the formation of a supramolecular helical chain. Compound
4 adopts a skew-trapezoidal bipyramidal geometry with the organo groups
lying over the plane of the two N,O-chelating carboxylate ligands and
being directed over the weaker Sn?N bonds. The in vitro antimicrobial
activities of 14 against a Gram-positive bacteria strain (Bacillus
subtilis), a Gram-negative bacteria strain (Escherichia coli) and
against Candida albicans were studied and compared with the
antimicrobial activities of Ph2SnL2 and Me2SnL2, and with the
antimicrobial standards gentamicin, tetracycline, ampicillin and
penicillin. All organotin compounds displayed remarkable antibacterial
activities that were comparable to those of the standard drugs, in
particular against B. subtilis, where the activity was correlated with
the number of Cl substituents. Copyright (C) 2012 John Wiley & Sons,
Ltd.
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