Synthesis and characterization of two new hydroxamic acids derivatives and their metal complexes. An investigation on the keto/enol, E/Z and hydroxamate/hydroxirnate forms

Abstract

2-phenylbenzimidazole-N-acetohydroxamic acid (HL1), 2-phenylbenzimidazole-N-butanohydroxamic acid (HL2) and Ni(II), Cu(II), Zn(II) and Cd(II) metal complexes have been synthesized and characterized by elemental analyses, H-1 NMR, C-13 NMR, FT-IR spectrometry, LC-MS (ESI+) and thermal analyses. the results of NMR spectra and theoretical calculations showed that the hydroxamic acids were in the keto-E and keto-Z conformations. the elemental analysis and thermal analysis indicated that M:L ratio of the complexes are 1:1 and the spectral analysis confirmed that hydroxamate groups are keto form in the Ni(II) and Zn(II) complexes of 2-phenylbenzimidazole-N-butanohydroxamic acid and enol form in the other complexes. (C) 2016 Elsevier B.V. All rights reserved.