Structural, luminescence and biological studies of trivalent lanthanide complexes with N,N′-bis(2-hydroxynaphthylmethylidene)-1,3-propanediamine Schiff base ligand

► Ln(III) ion adopts an eight-coordinate geometry. ► Luminescence spectra of Sm-LIII and Tb-LIII complexes display the metal centered line emission. ► Energy transfer process from LIII to Sm in Sm-LIII complex is more efficient than to Tb in Tb-LIII complex. ► Ln(III) complexes may serve as models for biologically important species.