Stabilities and coordination modes of glycinephosphonic acid in copper(II) heteroligand complexes with ethylenediamine, diethylenetriamine or N,N,N′,N′,N″-pentamethyldiethylene triamine in aqueous solution

• Published in: Structural chemistry 2010, Vol.21 (2), p.347-355
• Main Authors: Kamecka, Anna, Kurzak, Barbara, Jezierska, Julia, Woźna, Agnieszka, Broda, Marcin
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Computer Applications in Chemistry; Original Paper; Physical Chemistry; Theoretical and Computational Chemistry
• ISSN: 1040-0400; 1572-9001
• DOI: 10.1007/s11224-009-9534-9

Solution equilibrium studies on the Cu(II)-polyamine-(aminomethyl)phosphonic acid (glycinephosphonic acid) ternary systems (polyamine: ethylenediamine (en), diethylenetriamine (dien), N , N , N ′, N ′, N ″-pentamethyldiethylenetriamine (Me 5 dien)) have been performed by pH-potentiometry, UV–vis spectrophotometry and EPR methods. The obtained results suggest the formation of the heteroligand complexes with [Cu(A)(Gly(P))] stoichiometry in all studied systems. Additionally, in the systems with dien the protonated [Cu(dien)(H–Gly(P))] + species also exists in acid solution and in the system with en the [Cu(en)(Gly(P))H -1 ] − species is formed in the basic solution. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(Gly(P))] species, the geometry slightly deviated from square pyramidal for the [Cu(dien)(Gly(P))] complex and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me 5 dien)(Gly(P))] species. The coordination modes in these heteroligand complexes are discussed.