A comparative study of the coordination behavior of (Z)-4-[(2-(4,8-dimethylquinolin-2-yl)hydrazono) methyl] benzene-1,3-diol towards copper(II), nickel(II) and cobalt(II)-chlorides

摘要

The reaction of the titled hydrazone with Co(II), Ni(II) and Cu(II)- chlorides in absence and presence of KOH afforded mononuclear and binuclear complexes. The binuclear complexes support either enhancement of the phenoxy bridging or change of the coordination behavior of the studied hydrazone. Most complexes have the preferable Oh geometry (1-4), whereas complexes 5 and 6 have Td and square pyramid arrangements. As is evidenced from its -eff value = 3.98 BM, complex 5 acquires a tetrahedral arrangement around the Ni(II)- ion. The hydrazone ligand has a reformed character i.e. it changes its coordination behavior towards the transition metal ions as a result of the basicity of the reaction medium. In absence of KOH, the Cu(II) and Ni(II)- complexes revealed their higher affinity for NN- donors and the ligand behaves as a neutral species. Extensive spectroscopic and analytical studies were done to support the suggested structures of the complexes.