Syntheses, Structures And Magnetic Properties Of Metal Complexes Based On Nitrogen-Rich Schiff Base Ligands

Recently, the scholars have paid much attention to the functional complexes with specific physical or chemical properties, not only because of their molecular structures with controlled topolopy, but also because of their luminescent, electronic, magnetic and porous properties. In this field, we have carried out the research on the syntheses, crystal structures and magnetic properties of transition metal complexes, lanthanide complexes and heterometallic complexes using Schiff-base ligands with multiple nitrogen atoms. We have synthesized nine complexes, and the main contents as following:1. Two heterometallic complexes have been synthesized with1,2-Bis(2-hydroxy-3-methoxybenzylidene) hydrazine (H2L1):Dy1oCo2(C16H14N2O4)4(OAc)16(SCN)2(CH3CN)2(H2O)4(OH)2(μ-OH)4]·2Co(SCN)4H2O·2CH3CN·2H2O (1) and [Co2Na2(C16H14N2O4)2(N3)2(CH3O)2(H2O)2(CH3OH)]n (2); Three multinuclear transition metal complexes have been synthesized with N1, N3-bis(3-methoxysalicylidene)diethylenetriamine)(H2L2):[Mn2(C2oH23N3O4)2Cl3]·H3O·2CH3CN·4H2O (3)[Co2(C2oH23N3O4)2(OAc)2]·2CH3OH·2H2O (4) and [Cu4(C20H23N3O4)2(OAC)4]·2CH3OH·2C2H5OH (5).2. A dinuclear dysprosium complex and two mononuclear transition metal complexes have been synthesized with N’-((2-hydroxy-1-naphthyl)methylene)benzohydrazide (H2L3):[Dy2(C18H14N2O2)4(CO3)]·4H2O (6),[Cu(C18H12N2O2)(C5H5N)](8) and [Co(C18H12N2O2)(C5H8O2)(CH3OH)]H2O (9); A dinuclear dysprosium complex has been synthesized with N’-((2-hydroxy-1-naphthyl)methylene) picolinohydrazide (H2L4):[Dy2(C17H13N3O2)2(NO3)2(CH3OH)2]·4CH3CN (7).These ligands display a variety of coordination fashion, such as monodentate/bidentate bridging, chelating and chelating bridging. The temperature dependence of the direct current magnetic susceptibility of complexes (1,3,5,6,7) was measured, which revealed that the complexes1,3,5, and6exhibit anti-ferromagnetic interactions while complex7exhibit ferromagnetic interactions. Furthermore, different complexes1,6and7show interesting single-molecule magnet behaviour.