Synthesis and structure of complexes (NiII, AgI) of substituted benzaldehyde thiosemicarbazones and antitubercular activity of NiII complex

Complexes of 4-chlorobenzaldehyde thosemicarbazone ((HL)-L-1) with Ni(H), [Ni(L-1)(2)] 1 and Ag(I), [Ag-2(mu-X)(2)(eta(1)-S-(HL)-L-1)(2)(PPh3)(2)] (X = Cl, 2; Br, 3) have been synthesized and characterized by elemental analysis, IR and H-1 NMR spectroscopy. Ag(I) complexes, containing the 4-methylbenzaldehyde thiosemicarbazone ((HL)-L-2) ligand complexes [Ag-2 (mu-X)(2)(eta(1)-S-(HL)-L-2)(2)(PPh3)(2)] (X = Cl, 4; Br, 5) have also been synthesized. Complexes 1, 3 and 4 are also characterized by single crystal crystallography to investigate the effect of substituent at phenyl ring of the thiosemicarbazone on the bonding behavior of these Ag(I) complexes. (HL)-L-1 and its Ni(II) complexes were evaluated for their anti-tubercular activities and it was found that the anti-TB actitivy of (HL)-L-1 was enhanced on complexation with Ni(II) for complex 1. Molecular docking of (HL)-L-1 and its nickel complex has also been examined. The results of these studies support the molecular design of the these molecules and have provided a significant background to further examine their antitubercular activity.