New cyclic tetranuclear copper(II) complexes containing quadrilateral cores: Synthesis, structure, spectroscopy and their interactions with DNA in aqueous solution

Giri, Gopal C and Haldar, Shobhraj and Ghosh, Aloke Kumar and Chowdhury, Priyanka and Carrella, Luca and Ghosh, Utpal and Bera, Manindranath (2017) New cyclic tetranuclear copper(II) complexes containing quadrilateral cores: Synthesis, structure, spectroscopy and their interactions with DNA in aqueous solution. In: Journal of Molecular Structure, 1142 . pp. 175-184. ISSN 00222860

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Abstract

Three new cyclic tetranuclear copper(II) complexes, Tetrakis{3-[(2-pyridylmethyl)-amino]-propionato}(tetrachloro)tetracopper(II)methanolhydrate (1·CH3OH·H2O), Tetrakis{3-[(2-pyridylmethyl)-amino]-propionato}(tetrathiocyanato)tetracopper(II) (2) and Tetrakis{3-[(2-pyridylmethyl)-amino]-propionato}(tetraazido)tetracopper(II) (3) have been synthesized by exploiting the chelating ability and bridging potential of a carboxyamine functionalized tridentate ligand, HL (HL = 3-[(2-Pyridylmethyl)-amino]-propionic acid). Complexes 1, 2 and 3 have been synthesized by carrying out reaction of the ligand HL with stoichiometric amounts of CuCl2·2H2O, CuCl2·2H2O/NH4SCN, and CuCl2·2H2O/NaN3, respectively, in the presence of NMe4OH at ambient temperature. Various analytical techniques have been employed to characterize the complexes, including single crystal X-ray diffraction study of 1. Structures of complexes 2 and 3 have been optimized by DFT calculation at B3LYP/6-311G level. Analysis of X-ray crystal structure reveals that the metallic core of complex 1 contains four distorted square pyramidal Cu(II) ions. The Cu(II) ions in each complex are arranged at the corners of a quadrilateral showing a μ2:η1:η1 syn-anti bidentate bridging mode of four carboxylate groups of L− ligands with each bridging between two Cu(II) ions. These complexes represent a new family of 16-MCCuII-4 metallocoronates with repeating -[CuII[sbnd]O[sbnd]C[sbnd]O]- units. In aqueous solution (pH∼7.5), the interactions of complexes with DNA have been investigated by UV–Vis and fluorescence titration spectroscopy, and viscosity measurements.

Item Type:	Journal Article
Publication:	Journal of Molecular Structure
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to the Elsevier B.V.
Keywords:	Carboxylate bridging; DNA binding; Spectroscopy; Tetracopper complex; Tridentate ligand
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	01 Jun 2022 05:00
Last Modified:	01 Jun 2022 05:00
URI:	https://eprints.iisc.ac.in/id/eprint/72873

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