Heteronuclear Glycinate Complexes of Fe(II), Fe(III) and Co(II), Their Model Parameters

Abstract

The system Fe(II)–Fe(III)–Co(II)–Gly–H2O was studied by the Clark–Nikolsky oxidation potential method at a temperature of 298.15 K, ionic strength of the solution [Na(H)CIO4] I = 1.0 mol/l. The formation of mononuclear and heteronuclear compounds of various compositions in the system was found: [FeHL(H2O)5]3+, [Fe(HL)2(H2O)4]3+, [Fe(HL)(OH)(H2O)4]2+, [СoL(H2O)5]+, [FeIIIСoIIL(H2O)11]4+, [FeIIIСoII(L)2(H2O)10]3+, [FeL(H2O)5]+, [Fe(HL)2(H2O)4]2+, [Fe(HL)(OH)(H2O)4]+ and [Fe(HL)(OH)2(H2O)3]0. The stability and model parameters of coordination compounds were calculated by the Yusupov oxidation function iteration method, and their coordination compound distribution diagrams were constructed. It was found that the heteronuclear complex [FeIIIСoIIL(H2O)11]4+ is the most stable, with an accumulation degree of 99.50%, and exists up to pH = 9.5.