Synthesis And Characterization Of Chiral Schiff Base Rare Earth And Transition Metal Complexes

Single-molecule magnets (SMMs) have been the subject of deep studies andcontinuous development owing to their unique magnetic properties and potentialapplications in information storage and quantum computing. Furthermore,Incorporating chiarity into molecular magnetic materials have been demonstrated tobe an effective approach to the synthesis and design of multifunctional materials withphoto-electric, photo-magentic, or multiferroics proerties.In this paper, a schiff base ligand (H2L) was synthesized firstly by reaction ofo-vanillin and D-plenylglycinol in methanol. And then, four heteronuclear complexesCo3Ln [(Ln=Tb (1), Dy (2), Ho (3), Er (4)（]1-4）were synthesized by solvent processbased on this chiral ligand. The complexes are isostructural, and crystalized intriclinic group of P4(3)2(1)2. The chirality of complexes were illustrated by CDspectrum. The dynamics of the magnetization of14were investigatedusingalternating-current (ac) magnetic susceptibility measurement. It reveals that1showthe typical features associated with slow magnetization relaxation of SMMs, wihle2exhibits similar SMMs behaviour under a dc field. In theses complexes, the Co(III)are diamagnetic ions, therefore, the SMMs behaviour of complexes are comes fromthe Ln(III) ion.A pair of chiral tetranuclear Fe(III) enantiomer (5-6) were obtained by similarself-assembly process based on H2L ligand. Complexes5-6show similar crystalstructure of1-4, and crystalized in monclinic group of P21. The CD spectrum of5-6show pairs of postive and negative Cotton effects indicating the chirality and opticalactivity of the enantiomer. However, a racemic tetranuclear Ni(III) complex (7) wassynthesized under similar conditions. Crystal structure analysis reveals that complex7crystallizes in triclinic group of P-1. Complexes5-7were characterized by UV-Visspectrum, FT-IR, TGA, magnetic measurement, CD spectra and Cyclic voltammetrymeasurements. The dc magnetic susceptibility of5and7show very strongferromagnetic interactions among metalic centers. No SMMs behaviour of acmagnetic susceptibilities were observed in5and7. CV curve shows that nickelcomplexes have REDOX peak.