Transition Met Chem (2014) 39:81–94
DOI 10.1007/s11243-013-9777-6
Nickel(II) complexes of polyhydroxybenzaldehyde N4thiosemicarbazones: synthesis, structural characterization
and antimicrobial activities
Hana Bashir Shawish • Mohammadjavad Paydar • Chung Yeng Looi •
Yi Li Wong • Elaheh Movahed • Siti Nadiah Abdul Halim • Won Fen Wong
Mohd-Rais Mustafa • Mohd Jamil Maah
•
Received: 15 July 2013 / Accepted: 25 October 2013 / Published online: 8 November 2013
Ó Springer Science+Business Media Dordrecht 2013
Abstract Nickel(II) complexes with 2,3-dihydroxybenzaldehyde N4-substituted thiosemicarbazone ligands (H3L1–
H3L4) have been synthesized and characterized with the aim
of evaluating the effect of N4 substitution in the thiosemicarbazone moiety on their coordination behavior and biological activities. Two series of nickel(II) complexes with
the general formulae [Ni(H3L)(H2L)]ClO4 and [Ni2(HL)2]
were characterized by analytical and spectral techniques.
The molecular structure of one of the complexes, namely,
[Ni(H3L4)(H2L4)]ClO4 was established by single crystal
X-ray diffraction studies. The crystal structure of this complex revealed that two H3L4 ligands are coordinated to
nickel(II) in different modes; one as a neutral tridentate ONS
ligand and the other is as a monoanionic tridentate (ONS-)
ligand. The antimicrobial activities of the compounds were
tested against 25 bacterial strains via the disc diffusion
method, and their minimum inhibitory concentration (MIC)
and minimum microbicidal concentration were evaluated
using microdilution methods. With a few exceptions, most of
the compounds exhibited low-to-moderate inhibitory activities against the tested bacterial strains. However, the complexes [Ni2(HL3)2] (7) and [Ni2(HL4)2] (8) indicated higher
inhibitory activity against Salmonella enterica ATCC 9068
H. B. Shawish Á S. N. A. Halim Á M. J. Maah (&)
Department of Chemistry, Faculty of Sciences, University of
Malaya, 50603...