One-pot synthesis, characterization, DNA binding and enzymatic studies of 4-methyl trans-cinnamate zinc(II)-mixed ligand complexes

Abstract

Four new zinc(II) complexes formulated as [Zn(L)2] (1), [Zn(L)2(phen)] (2), [Zn(L)2(bipy)H2O] (3), and [Zn(en)2(H2O)2](L)2(H2O)2 (4), where HL = 4-methyl trans-cinnamic acid, bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline, and en = ethylenediamine, have been synthesized and characterized by FT-IR and NMR spectroscopy. Single-crystal XRD revealed distorted square-pyramidal structure for 3 and octahedral for 4. The complexes were screened for DNA interaction via viscommetry and UV–visible spectroscopy. The apparent binding constants were calculated to be 1.18 × 104, 1.26 × 105, 4.64 × 104, and 1.89 × 104 for 1–4, respectively. The binding propensity to salmon sperm DNA was in the order: K2 > K3 > K4 > K1. Furthermore, these complexes demonstrated efficient inhibition of alkaline phosphatase, which was attributed to the binding of zinc(II) to the enzyme’s active site.