Synthesis, X-ray and spectroscopic characterisation of chromium(III) coordination compounds with benzimidazolic ligands

The syntheses and characterisation of chromium(III) complexes with tris(2-b enzimidazolylmethyl)amine (ntb), 2-guanidinobenzimidazole (2gb), 2,6-bis(2- benzimidazolyl)pyridine (bbimpy) and 2-(2-pyridyl)benzimidazole (2pb), of c omposition [Cr(ntb)Cl-2]Cl . 4.5H(2)O (1), [Cr(2gb)(3)]Cl[ZnCl4]. CH3OH (2) , [Cr(2gb)(3)]Cl-3. 4H(2)O (3), [Cr-2(2gb)(4)(mu-OH)(2)](ClO4)(4). 5H(2)O ( 4), [Cr(b-bimpy)Cl-3] (5) and [Cr(2pb)(2)Cl-2]Cl . C2H5OH . 0.5H(2)O (6) ar e presented. The compounds are obtained from Cr(III) in alcoholic solution, or a Cr(II) aqueous acidic solution. The latter were carried out under air -free conditions. The reaction of 2gb with Cr(II) in aqueous solution yield ed a dinuclear compound. The X-ray crystal structures of 1 and 4 are discus sed. (C) 2000 Elsevier Science Ltd. All rights reserved.