Study On Syntheses, Structures And Magnetic Properties Of Lanthanide-transition Metal Heterodinucler Complcxs Based On Chiral Schiff Base Ligands

Complexes with Schiff base ligands have been widely studied in the fields of biology,medicine, materials and chemistry for the excellent properties with antibacterial, anticancer,catalytic, et al. The salen(N,N′-disalicylideneethylenediamine dianion) ligands and itsanalogues as a special Schiff base can supply N2O2and O2O2coordinated model to form3d-4fheteronuclear complexes by coordinate to lanthanide and transition metal ions. And thefunction of3d-4f heteronuclear complexes can be improved by the addition of chirality. Therelevant researchs of chiral salen-type lanthanide-transition heteronuclear metal complexesare reported rarely. In this paper, we mainly studied the synthesis, structure and magnetic ofNi-Ln and Cu-Ln series salen complexes.Using chiral salen-type mononuclear Ni(II) complexes as precursor building blocks, fourheterodinuclear metal complexes:((S, S)-Ni-L-Ce(H2O)(NO3)3(1),(R, R)-Ni-L-Nd(H2O)(NO3)3(2),(S, S)-Ni-L-Ln(NO3)3(Ln=Sm (3), Dy (4))) were obtained by solution reactionmethod. Single-crystal X-ray diffraction measurements reveal that complexes1and2havethe same configuration, and complexes3and4are also isomorphous. Complexes1-4allcrystallized in achiral space gro1_up P. The structure of complexes1and2are mirrorsymmetry in three-dimensional space. The magnetic studies indicate that complex4exhibitsslow relaxation at low temperature, and its out-of-phase alternating current susceptibilitychange with frequencies, confirming that complex4is a single-molecule magnet.Using salen chiral mononuclear Cu(II) complexes as precursor building blocks, sevenheterodinuclear metal complexes (S, S)-Cu-Ce(H2O)(NO3)3(5),(S, S)-Cu-Nd(NO3)3·CH3CN(6),(S, S)-Ni-L-Tb(NO3)3(7),(R, R)-Cu-L-Dy(NO3)3(8) and (R, R)-[Cu-L-Ln(NO3)3]2(Ln=Ho (9), Er (10), Yb (11))were obtained by solution reaction method. The single-crystal X-raydiffraction revealed the complexes7and8, complexes9and10are the same configurationrespectively. Complexes5,7, and8crystallized in space group P1_, complexes6crystallizedin space group P21/c and complexes9-11crystallized in chiral space group P21. The magneticstudy revealed that complexes5and8are possesing the antiferromagnets and theantiferromagnetic coupling interaction existed between the metal ions. Complex8displayedweak ferromagnetism in the high temperature period and antiferromagnetism in lowtemperature period and it show the antiferromagnetic in whole temperature period.