Abstract

Synthesis, characterization, coordination, bonding and electronic behavior of an ONS pincer ligand with divalent iron, cobalt, copper and zinc are described. The ligand is synthesized by condensation of dihydroxybenzaldehyde with thiosemicarbazide. The reaction of the ligand with metal ions in 1:2 (M:L) stoichiometric in identical conditions resulted in two octahedral pincer type complexes with iron and cobalt in which two ligands extend a perpendicular shape-retaining the ligand’s linearity, and one trigonal bipyramidal pincer complex with zinc. For copper, the ligand preferred a bidentate coordination mode forming a square planar geometry. The structure of the copper complex can be viewed as a molecular hammock. Quantum mechanical studies at DFT level were undertaken to confirm the geometry, spectroscopic and electronic properties of all the complexes. The ability of the compounds to possess biological activity is tested against various pathogenic bacterial strains. The results show that the copper complex displays higher antimicrobial activities as compared to the ligand and other complexes. A remarkable change in the electronic spectrum of the ligand in the presence of cobalt ion in highly aqueous medium demonstrates its use as a metal sensor among a wide range of biological important metal ions.

摘要

描述了具有二价铁，钴，铜和锌的ONS钳位配体的合成，表征，配位，键合和电子行为。通过二羟基苯甲醛与硫代氨基脲的缩合合成配体。配体与金属离子在化学计量比为1：2（M：L）的相同条件下反应，生成了两个具有铁和钴的八面体钳型配合物，其中两个配体延伸了一个垂直形状，从而保持了配体的线性，以及一个三角双锥体锌夹钳。对于铜，配体优选形成方形平面几何形状的双齿配位模式。铜络合物的结构可以看作是分子吊床。在DFT级进行了量子力学研究，以确认几何形状，所有配合物的光谱和电子性质。测试了化合物对各种病原细菌菌株的生物活性。结果表明，与配体和其他配合物相比，铜配合物显示出更高的抗菌活性。在高水介质中存在钴离子的情况下，配体的电子光谱发生了显着变化，证明了其在广泛的重要生物金属离子中用作金属传感器。