Abstract
A series of racemic, heteronuclear complexes [Zn&sub2;Nd(ac)&sub2;(HL)&sub2;]NO&sub3;·3H&sub2;O (1), [Zn&sub2;Sm(ac)&sub2;(HL)&sub2;]NO&sub3;·3CH&sub3;OH·0.3H&sub2;O (2), [Zn&sub2;Ln(ac)&sub2;(HL)&sub2;]NO&sub3;·5.33H&sub2;O (3⁻5) (where HL is the dideprotonated form of N,N'-bis(5-bromo-3-methoxysalicylidene)-1,3-diamino-2-propanol, ac = acetate ion, and Ln = Eu (3), Tb (4), Dy (5), respectively) with an achiral multisite coordination Schiff base ligand (H&sub3;L) were synthesized and characterized. The X-ray crystallography revealed that the chirality in complexes is centered at lanthanide(III) ions due to two vicinally located μ-acetato-bridging ligands. The presented crystals have isoskeletal coordination units but they crystallize in monoclinic (1, 2) or trigonal crystal systems (3⁻5) with slightly different conformation. In 1 and 2 the ZnII⁻LnIII⁻ZnII coordination core is linear, whereas in isostructural crystals 3⁻5 the chiral coordination cores are bent and lie on a two-fold axis. The complexes 1, 3⁻5 show a blue emission attributed to the emission of the ligand. For ZnII&sub2;SmIII complex (2) the characteristic emission bands of f-f* transitions were observed. The magnetic properties for compounds 1, 4 and 5 are characteristic for the paramagnetism of the corresponding lanthanide(III) ions.