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

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 2,2ʹ-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 coefficient of 1.628 × 10-7 cm 2 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 × 10 4 and 1.438 × 10 4 M-1 using cyclic voltammetry and absorption spectroscopy, respectively. The preliminary studies heralded good structural and biological importance of the synthesized complex.

Binuclear copper(II) complexes: Synthesis, structural characterization, DNA binding and in silico studies

“…This absorption band is typical of distorted octahedral geometry in solution form, where the DMSO solvent molecule acts as ligand. 31 Figure 5B shows the absorption spectrum of complex 2, showing an absorption band at λmax = 289 nm due to π-π electronic transition of the aromatic moiety in the complex and a weak absorption peak at 510 nm due to d-d transition in copper(II) ion. This also corresponds to distorted octahedral geometry where the solvent DMSO is attached at the sixth position to copper ion in the solution form.…”

Mononuclear vs. binuclear carboxylates of copper(II) with 2,2′‐bipyridine: Synthesis, characterization, structural description, and properties

“…Absorption spectroscopy yielded broad bands at λ max = 658 and 676 nm (upper most peak in Figures A and A), which are ascribed to transitions of Cu 2+ ion in a six‐coordinated complex as observed in other copper complexes in solution . As complex 2 has square pyramidal geometry in solid state, there might be attachment of a DMSO molecule to a copper ion in solution to form an octahedral coordination around the metal ion.…”

“…The ESR spectrum is typical of other octahedral copper(II) complexes . The ESR spectrum of complex 2, as shown in Figure b, is similar to other copper(II) complexes with partially resolved hyperfine splitting, with g ┴ values of 2.06161 2.24623 and 1.94959 . The ESR spectrum supports the dinuclear nature of the copper(II) complex.…”

“…The binuclear copper(II) carboxylates containing 2,2′‐bipyridine present more structural diversity. There is one bipyridine unit attached to each copper ion of the dimer or two bipyridine ligands attached to each copper ion . The former category contains diverse bridging groups between copper ions such as hydroxyl and water, carboxylate, chloro‐, or mixed bridging groups .…”