Аннотация:Complexation of FeII and FeIII with azaheterocyclic ligands L (L = phen or bipy) were studied in the presence and in the absence of boron cluster anions [BnHn]2– (n = 10, 12). The reactions were carried out in air at room temperature in organic solvents and/or water. In all the solvents used, well known [FeL3]An (An = 2Cl– or SO42–) ferrous complexes were formed from FeII salts. Composition of ferric complexes with L ligands depends on the nature of solvent: either dinuclear oxo-iron(III) chlorides [L2ClFeIII–O–FeIIIL2Cl]Cl2 or ferric ferrates(III) [FeIIIL2Cl2][FeIIICl4], or [FeIIIL2Cl2][FeIIICl4L] were isolated from FeIII salts. Introduction of the closo-borate anions to a Fe3+(or Fe2+)/L/solv. mixture stabilizes ferrous cationic complexes [FeL3]2+ in all the solvents used: only ferrous [FeL3][BnHn] (n = 10, 12) complexes were isolated from all the reaction mixtures in the presence of boron cluster anions.