Exploration Of Spin Crossover Based On Derivatives Of 1,2,4-triazole As Ligand

Spin crossover has potential applications in thermal display, optical switch and pressure sensor, which is regarded the most promising applied materials currently and has been an active area in molecular magnetic materials. The Fe-1,2,4-triazole system has been found to be particularly suited towards generating spin crossover behavior. Here, we design and synthesize a new ligand of derivatives of 1,2,4-triazole,and use it to explore new spin crossover system.This thesis has three chaptersIn the first chapter, a survey on the development of molecular-based magnets, especially, spin crossover is concisely presented along with the research significance and the results of this thesis.In the second chapter, the rational design of a ligand with hydroxyl and phenyl has been outlined. Then, single crystalline [Fe2(Saltrz)5(SCN)4]·4CH3OH (1) and [Co2(Saltrz)5(SCN)4]·4CH3OH (2) have been prepared. The structures and magnetism of these complexes have been investigated by X-ray diffraction method and magnetic measurements. The experimental results indicated that [Fe2(Saltrz)5(SCN)4]·4CH3OH (1) exhibits very abrupt spin crossover phenomenon at 165 K.In the third chapter, we investigate the effect of slight structural variations for magnetic property. Magnetic exchange interactions are structure dependent, slight structural variations could also effect on the magnetic properties of compound. McInnes et al reported two decanuclear cyclic Cr(III) complexes with homo-ligands. We synthesize [Cr10(μ-O2CMe)10(μ-OMe)10(μ-OEt)10] with hetero-ligands and compare with Cr10 of homo-ligand ones.