Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1340362 | Polyhedron | 2008 | 7 Pages |
Solution equilibrium studies on the Cu(II)–polyamine–histidine ternary systems (polyamine: ethylenediamine (en), diethylenetriamine (dien), N,N,N′,N″,N″-pentamethyldiethylenetriamine (Me5dien)) have been performed by pH-potentiometry, UV–Vis spectrophotometry and EPR methods. The obtained results suggest the formation of the mixed-ligand complexes with [Cu(A)(His)]+ stoichiometry in all studied systems. Additionally, in the systems with dien and Me5dien protonated [Cu(A)(H–His)]2+ species also exists in acid solution. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(His)]+, the geometry slightly deviated from square pyramidal for the [Cu(dien)(His)]+ and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me5dien)(His)]+ species. The coordination modes in these mixed-ligand complexes are discussed.
Graphical abstractSolution equilibrium studies on the Cu(II)–polyamine–histidine ternary systems (polyamine: ethylenediamine, diethylenetriamine, N,N,N′,N″,N″-pentamethyldiethylenetriamine) have been performed by pH-potentiometry, UV–Vis spectrophotometry and EPR methods. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(His)]+, the geometry slightly deviated from square pyramidal for the [Cu(dien)(His)]+ and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me5dien)(His)]+ species.Figure optionsDownload full-size imageDownload as PowerPoint slide