Syntheses, structures, and properties of Ni(II) complexes with 5,5′-bis(4-halogenphenyl)diazo-dipyrromethane

Abstract

Ni(II) complexes with 5,5′-bis(4-halogenphenyl)diazo-dipyrromethane have been synthesized and characterized by X-ray crystallography. All the complexes have similar crystal structures in which Ni(II) is square-planar by coordinating to two pyrrole and two azo nitrogen atoms. The azo-pyrroles of the ligands can be converted to the hydrazone tautomer after complexing nickel. Moreover, the C–H ··· Ni interaction played an important role in directing self-assembly of the complexes. The UV-Vis spectra of the complexes showed great difference with the metal complexes of pyrrol-2-imine.

Keywords:

• Diazo-dipyrromethane
• Metal complex
• Azo-hydrazone tautomerism
• C–H ··· Ni interaction

Acknowledgments

We sincerely thank the Natural Science Foundation of China (NSFC Nos. 20702038 and 21172174) for the financial support.