Tetrahedral manganese(II) complexes of 1-alkyl-2-(arylazo)imidazoles. X-ray crystal structure of [Mn(HaaiMe)4](ClO4)2·DMF (HaaiMe = 1-methyl-2-(phenylazo)imidazole)

Abstract

[Mn(RaaiR′)4](ClO4)2 complexes have been synthesised by reacting Mn(ClO4)2·6H2O and RaaiR′ in methanol (RaaiR′ = 1-alkyl-2-arylazo)imidazole, R = H (a), Me (b), Cl (c); R′ = Me (1), Et (2)). The orange–red crystalline compounds were characterised by microanalytical, spectroscopic, magnetic, thermal and electrochemical data. A single-crystal X-ray diffraction study of a DMF adduct of 1a revealed tetrahedral orientation of four ligands coordinating through imidazole-N while the azophenyl group (–N=N–Ph) is pendant. Cyclic voltammetry shows the Mn(III)/Mn(II) couple at > 1.0 V along with azo reductions.