Syntheses and characterizations of a series of heptanuclear octahedral polyhedra {LnNi6} with different amino acids as ligands in aqueous media

Heptanuclear octahedral clusters [LnNi6(AA)12]3+ (Ln = La, Pr) were obtained through the reaction of Ln3+, Ni2+ and amino acid (AA = glycine, l-alanine or l-threonine) in aqueous solution. In the cluster, the Ln3+ ion is in the center of the octahedral cage formed by six nickel atoms.