Designing of homo and heteroleptic zinc(II) carboxylates: synthesis, spectroscopic characterizations, DNA binding study, CTAB interaction and in vitro antimicrobial evaluations

Synthesis of two homoleptic and five heteroleptic zinc (II) carboxylate complexes with two different ligands: HL1 = 3-chlorobenzoic acid and HL2 = 2-(4-chlorophenyl) acetic acid have been reported in this paper. The general formulae of the two homoleptic complexes are: Zn(L1)2(1), and Zn(L2)2(2). Similarly, the general formulae for two different types of heteroleptic complexes are: (Type-I): [(Zn)2(L1)4(bipy)2(H2O)] (3), [Zn(L2)2(bipy)(H2O)] (4) and (Type-II): [ZnL1L2] (5), [ZnL1L2(py)] (6) and [ZnL1L2(bipy)] (7). The synthesized complexes were characterized in the solid state by FT-IR, CHN analyses and in solution state by NMR (1H, 13C) spectroscopy. Complexes 3 and 4 were also characterized by single crystal analysis where data revealed that the geometry around each Zn atom is distorted trigonal bipyramidal and octahedral, respectively. The synthesized complexes were interacted with SS-DNA and CTAB (surfactant). Interaction of the synthesized compounds with SS-DNA was studied by UV–visible spectroscopy and viscometry and intercalative mode of interaction was exhibited. Moreover, the interaction of the synthesized complexes with CTAB was studied by conductometry showing a strong binding that is evident from higher CMC and negative Gibbs free energy of micellization (ΔGm) values. The tested compounds were further screened for in vitro antibacterial and antifungal activities and were found active against the studied strains of bacteria and fungus.