Dinuclear Ternary Copper(II) Complex: Synthesis, Characterization, Structure and DNA-Binding Studies

Muhammad Iqbal,Saqib Ali,Paul A Anderson,Manzar Sohail,Afifa Mushtaq

doi:10.17344/acsi.2018.4695

Abstract

A dinuclear centrosymmetric copper(II) complex has been prepared and characterized via FT-IR, UV-Visible and electron spin resonance spectroscopy, electrochemical method, and powder and single crystal XRD techniques. The two copper(II) ions are connected by two μ-1,1-O atoms belonging to para-fluorophenyl acetate ligands. Each copper(II) ion is coordinated by two other carboxylate ligands in monodentate and a 2,2'-bipyridine molecule in bidentate manner. Thus the geometry around each penta-coordinated copper(II) ion is square pyramidal with distortion factor τ = 0.04. Purity and uniform crystalline nature of the complex was assessed from powder XRD spectrum. ESR signal consisted of partially resolved hyperfine splitting pattern while electrochemical studies revealed diffusion controlled electron transfer processes with diffusion co-efficient of 1.628×10-7 cm2 s-1. The results of all spectroscopic experiments support each other. The complex afforded mixed binding mode with DNA yielding DNA-binding constant values of 3.667×104and 1.438×104 M-1 using cyclic voltammetry and absorption spectroscopy, respectively. The preliminary studies heralded good structural and biological importance of the synthesized complex.

Highlights

Binuclear copper(II) carboxylates with 2,2ʹ-bipyridine adopt diverse bridging groups which affect their properties
This paper reports the synthesis, characterization and DNA-binding properties of a double 1,1-O-bridging copper(II) carboxylate containing biologically important ligand 2,2ʹ-bipyridine
The complex has been characterized by various analytical techniques such as infra-red, UV-Visible and electron spin resonance spectroscopy as well as powder and single crystal X-ray diffraction while the purity level of the complex was confirmed by powder the complex in the region 506 cm−1, attributable to a Cu–N vibration further supported it.[19]

Summary

Introduction

Binuclear copper(II) carboxylates with 2,2ʹ-bipyridine adopt diverse bridging groups which affect their properties. There can be single bridging group such as a trans-bidentate ligand like 1,4-dibenzoate ion.[1] Such relatively longer spacer ligand precludes the possibility of electronic interaction between two copper(II) ions of the binuclear molecule. In such binuclear copper(II) complexes the observed EPR signal is typical of monomeric complexes with g ~ 2.2 Another common bridging group in binuclear copper(II) complexes is chlorine[3] where the dichloro-bridged dinuclear complexes with 2,2ʹ-bipyridine were found catalytically more active than their mono-nuclear analogue.[3] Some complexes contain water molecules bridging the two copper(II) centers[4] where the weaker super-exchange interactions in analogues containing. The 1,2-bridging mode of carboxylate[5] as well as thio-carboxylate ligand[6] is common, it is able to bridge two metal centers of dinuclear complexes in 1,1-O-bridging fashion as in phenyl acetate

Methods

Results

Conclusion