A five-coordinate copper(II) perchlorate complex with tris(N-methylbenzimidazol-2-ylmethyl)amine and salicylate

Abstract

A five-coordinate copper(II) complex with the tripod ligand tris(N-methylbenzimidazol-2-ylmethyl)amine (Mentb) and salicylate, with the composition [Cu(Mentb) (salicylate)](ClO₄) · 2DMF, was synthesized and characterized by elemental and thermal analyses, electrical conductivity, IR and UV-Vis spectral measurements. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. The Cu(II) is five-coordinate with four N atoms from the Mentb ligand and an O atom of the monodentate salicylate ligand. The N₄O donors are in a distorted trigonal-bipyramid geometry. Cyclic voltammograms indicate a quasireversible Cu²⁺/Cu⁺ couple. The X-band EPR spectrum of the complex confirms the trigonal-bipyramidal structure with g_∥ < g _⊥ and a very small value of A_∥ (41 × 10⁻⁴ cm⁻¹).

Keywords:

• Tris(N-methylbenzimidazol-2-ylmethyl)amine
• Crystal structure
• EPR
• Cyclic voltammetry
• Copper(II)complexes

Acknowledgements

The authors acknowledge the financial support and grant from ‘Qing Lan’ Talent Engineering Funds and Students’ Science and Technology Innovation Funds (grant no. DXS2008-040, 041) by Lanzhou Jiaotong University. The grant from the Middle-Young Age Science Foundation (grant no. 3YS061-A25-023) and ‘Long Yuan Qing Nian’ of Gansu Province is also acknowledged.