Synthesis, structure, spectral characterization and DNA binding affinity of new water soluble trinuclear copper(II) complexes with partial cubane Cu3O4 cores. (15th October 2015)

• Record Type: Journal Article
• Authors: Giri, Gopal C.; Haldar, Shobhraj; Carrella, Luca; Panda, Asit B.; Musie, Ghezai T.; Bera, Manindranath
• Is Part Of: Polyhedron. Volume 99(2015)
• Page Start: 7
• Page End: 16
• Publication Date: 2015-10-15
• Subjects: Trinuclear copper -- Carboxylate bridging -- X-ray structure -- Spectroscopy -- DNA binding; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2015.06.018
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Two new water soluble trinuclear copper(II) complexes, [Na6 (H3 O)4 ][Cu3 (cbal)3 (μ3 -OH)(H2 O)3 ]4 (ClO4 )6 ·3H2 O (1 ) and [K(H2 O)2 ][Cu3 (cbal)3 (μ3 -OH)(H2 O)]·3.75H2 O (2 ) have been prepared via the reaction of an unsymmetrical amino dicarboxylic ligand, N-(2-carboxybenzomethyl)-β-alanine (H2 cbal), Cu(ClO4 )2 ·6H2 O and NaOH/K2 CO3, and characterized. The X-ray crystal structure analyses reveal that the three copper centers are at the corners of an equilateral triangle in complex1, whereas in complex2, the three copper centers are at the corners of a scalene triangle. Both the two complexes are investigated for their binding affinity with CT-DNA in aqueous solution at physiological pH using a combined approach of UV–Vis and fluorescence spectroscopic techniques. Abstract: Two new water soluble trinuclear copper(II) complexes, [Na6 (H3 O)4 ][Cu3 (cbal)3 (μ3 -OH)(H2 O)3 ]4 (ClO4 )6 ·3H2 O (1 ) and [K(H2 O)2 ][Cu3 (cbal)3 (μ3 -OH)(H2 O)]·3.75H2 O (2 ) have been synthesized in good yield via the reaction of an unsymmetrical amino dicarboxylic ligand, N-(2-carboxybenzomethyl)-β-alanine (H2 cbal), Cu(ClO4 )2 ·6H2 O and NaOH/K2 CO3 in methanol at room temperature. Complexes1 and2 have been characterized by elemental analysis, room temperature magnetic susceptibility measurements, FTIR, UV–Vis, mass spectrometry and single crystal X-ray crystallography. Both complexes contain a partial cubane [Cu3 O4 ] core consisting of the trinuclear [{Cu(cbal)}3 (μ3 -OH)(H2 O)3 ] − and [{Cu(cbal)}3 (μ3 -OH)(H2 O)] − unit, respectively. While the X-ray crystal structure of complex1 reveals that the three copper(II) ions are in a distorted octahedral geometry forming an equilateral triangle, complex2 shows that one copper(II) ion is in a distorted square pyramidal geometry, the other copper(II) ions are in a distorted trigonal bipyramidal and a distorted octahedral geometry forming a scalene triangle. Complexes1 and2 are investigated for their binding affinity towards CT-DNA in aqueous medium at pH ∼ 7.5 using UV–Vis and fluorescence spectroscopic techniques. DFT calculation has been performed to calculate the Fukui functions at the metal sites as well as HOMOs and LUMOs in complexes1 and2 to elucidate the possible binding site with the DNA.