Azacyclo-auxiliary ligand-tuned SMMs of dibenzoylmethane Dy(III) complexes

A series of four beta-diketone mononuclear dysprosium complexes, namely, Dy(DBM)(3)(bpy) (1), Dy(DBM)(3)(phen)center dot Tol (2), Dy(DBM)(3)(dpq)center dot Tol (3), and Dy(DBM)(3)(dppz) (4) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dpq = dipyrazine[2,3-f: 2',3'-h] quinoxaline, dppz = dipyrido[3,2-a:2',3'-c] phenazine, Tol = toluene) have been isolated by the reactions of dibenzoylmethane (DBM), azacyclo-auxiliary ligands and DyCl3 center dot 6H(2)O. X-ray crystallographic analysis reveals that complexes 1-4 are all eight-coordinate mononuclear structures. The azacyclo-auxiliary ligands have a dramatic effect on the structure and magnetic characteristics of complexes 1-4, originating from the different degrees of deviation from the ideal coordination symmetries. Complexes 1 and 2 display a single relaxation mode under 0 Oe and complexes 3 and 4 display two single relaxation modes under 2000 Oe.