Synthesis, characterization and structure of mononuclear cobalt( III) carbonato complexes containing a tailored tetradentate amine as an end-capping ligand

Department of Chemistry, The University of Burdwan, Burdwan-713 104, West Bengal, India

E-mail : barin_1@yahoo.co.uk Fax : 91-342-2530452

Molecular Structure Laboratory, School of Chemistry, The University of St. Andrews, Purdie Building,

St. Andrews, Fife, K Y 16 9ST, UK

Manuscript received 18 November 2010, revised 05 July 2011, accepted 21 July 2011

Two hexacoordinated mononuclear compounds of the type [Co(L)(C0₃)]CI0₄/PF₆ (1/2) [L = N,N'-bis(3- aminopropyl)-1,2-ethanediamine] have been synthesized and characterized using microanalytical, spectroscopic and other physicochemical results. Single crystal X-ray structural analysis shows that the metal center in 1 adopts a distorted octahedral geometry with a CoN₄O₂ chromophore. Hexacoordination of cobalt(lll) is attained by binding with four N atoms of L and two O atoms of a chelated carbonate ion. Multiple intermolecular N-H^....O hydrogen bondings in I result in a 2D sheet structure. In MeCN solutions, the diamagnetic compounds show a nearly reversible one-electron reductive response corresponding to cobalt(III)-cobalt(II) couple.