Preparation and physico-chemical characterisation of iron(III) complexes containing substituted benzimidazole and Schiff base moieties

New complexes of iron(III) of the type [(mu-Cl)(2)Fe-2{eta(2)-(opbz)(4)] (1) and [(Cl)(2)Fe{eta(2)-(opbz)] (2) [Hopbz = {2-(o-hydroxyphenyl)}-benzimidazole, eta(2) = Number of connectivity sites involved in bonding the metal] have been synthesized by the interactions of iron(III) chloride with the corresponding ligand (Hopbz) in 1:2 and 1:1 molar ratio(s) in hot EtOH. The complex (1) was further treated with various sodium salts of Schiff bases (sb) [Na(o-smab), Na(p-smab) and Na(sap)], alkoxo-Na(OPri), aryloxo-Na(OAr) and tetraisopropoxyaluminate [Na{Al(OPri)(4)] in a 1:1 molar ratio (in THF-benzene medium) to produce derivatives of the type: {(eta(2)-(sb) Fe{eta(2)- opbz)(2)] (3), (4) and (5), [(mu-OPri)(2)Fe-2{eta-(opbz)(4)}] (6) [(mu-OAr)(2)Fe-2{eta-(opbz)(4)}] (7) and [(mu-OPri)(2)Al(O-Pr-i)(2)-Fe{eta-(opbz)(2)}] (8). All these derivatives were characterised by elemental analysis, spectral (IR, UV-visible and FAB-mass) and magnetic susceptibility measurements. On the basis of these studies, a distorted octahedral (dimeric) geometry around iron(III) for the complexes (1), (6), (7) and (8) have been suggested.