Nuclease activity of mixed ligand complexes of copper(II) with heteroaromatic derivatives and picoline

New picoline adducts with carbamic acid [(furan-2-yl)methylene]hydrazide-Cu-II (CFMH) (1); thiocarbamic acid [(furan-2-yl)methylene]hydrazide-Cu-II (TFMH) (2); carbamic acid [(furan-2-yl)ethylidene]hydrazide-Cu-II (CFEH) (3), thiocarbamic acid [(furan-2-yl)ethylidene]hydrazide-Cu-II (TFEH) (4); carbamic acid [(thiophene-2-yl) methylene]hydrazide-Cu-II (CTMH) (5), thiocarbamic acid [(thiophene-2-yl)methylene]hydrazide-Cu-II (TTMH) (6), carbamic acid [(thiophene-2-yl)ethylidene]hydrazide-Cu-II (CTEH) (7), thiocarbamic acid [(thiophene-2-yl)ethylidene]hydrazide-Cu-II (TTEH) (8) have been prepared and characterized by analytical, i.r., electronic, e.s.r. and c.v. spectral data. The electronic spectra suggest distorted octahedral geometry for all the picoline adducts. E.s.r. g(parallel to) values lie between 2.251-2.286 at l.n.t. All the adducts undergo a quasi-reversible one-electron reduction in the range +0.47 to +0.51 V versus s.c.e., attributable to the Cu-III/Cu-II redox couple. The electron transfer is much faster in the semicarbazone complexes than in the thiosemicarbazone complexes. All adducts showed increased nuclease activity in the presence of oxidant; the nuclease activity is compared with that of the parent copper(II) complexes.