Construction of mononuclear transition metal(II) complexes with bi- and tridentate, neutral hydrazone ligands with a quinoxaline hub

Abstract

A series of Co(II), Ni(II), Cu(II), and Zn(II) complexes of bi- and tridentate hydrazones were prepared. Ligands L¹ and L² were synthesized by the condensation of 2-mercapto-3-hydrazinoquinoxaline with 2-hydroxy-3-formylquinoline and 3-acetylcoumarin, respectively. The compounds were characterized by various spectro-analytical techniques and magnetic moment studies. The complexes are found to be monomeric and non-electrolytes. In these complexes, [CuL¹Cl₂] has square pyramidal geometry and others have octahedral. The copper complexes are electrochemically active in the applied potential range.

Keywords:

• Quinoxaline
• Quinoline
• Coumarin
• SNO donor system

Acknowledgments

The authors thank the Department of Chemistry and USIC, Karnatak University, Dharwad, for providing research and spectral facilities. Recording of FAB mass spectra (CDRI Lucknow) and EPR spectra (IIT Bombay) are gratefully acknowledged. Further, the authors thank UGC and Karnatak University for providing research fellowships.