Synthesis, Structure and DNA-Binding Studies of Oxamido-Bridged Binuclear Copper(II) Complex: [Cu2(heap)](bipy)(ClO4)2

Abstract

A new μ-oxamido-bridged copper(II)–copper(II) binuclear complex with formula of [Cu2(heap)](bipy)(ClO4)2, where H2heap and bipy are N,N′-bis(N-hydroxyethylaminopropyl)-oxamide and 4,4′-bipyridine, respectively, has been synthesized and characterized by elemental analyses, molar conductivity measurement, IR and electronic spectra studies, and single-crystal X-ray diffraction. The single-crystal X-ray analysis reveals that the complex has two embedded inversion centers at the mid-points of the C6–C6i bond of the oxamido group and the C7–C7ii bond of the 4,4′-bipyridine, respectively [symmetry code: (i) 2−x, 1−y, 1−z; (ii) =2−x, −y, 1−z]. Copper(II) atom is in a square-planar coordination geometry. The Cu···Cu separation through the oxamido birdge is 5.1430(8) A. The bridging ligand (heap2−) adopts a bis-tetradentate trans conformation. A one-dimensional hydrogen bonding supramolecular structure parallel to the [2 1 0] direction is found in the crystal. The interaction of the binuclear copper(II) complex with herring sperm DNA (HS-DNA) was investigated by using absorption and emission spectra, electrochemical techniques and viscometry. The results suggest that the binuclear copper(II) complex interacts with HS-DNA by electrostatic interaction with intrinsic binding constant of 1.54 × 104 M−1. A new µ-oxamido-bridged copper(II)–copper(II) binuclear has been synthesized and characterized by single-crystal X-ray diffraction. The interaction of the binuclear copper(II) complex with herring sperm DNA (HS-DNA) was investigated.