Synthesis And Magnetic Properties Of The Ligand To The Mnt New Complexes

The study of Intermolecular magnetic coupling mechanism is one of most studiedtopics in molecule-based magnetic area in recent decade. Some radicalintermolecular interaction or radical inter-ion interaction have exhibited strongintermolecular magnetic coupling and therefore much attention has been focusedin this branch. But the intermolecular magnetic coupling mechanism is nowherenear understanding. mnt (cis-1,2-dicyanoethylene-1,2-dithiolate) is one of usefulligand that can coordinate metal ion, which leads to radical coordination anion. Ifdifferent counter cations are selected, all kinds of coordinated anions can beobtained, in which there are different intermolecular interactions. Therefore, it willbenefit understanding the intermolecular magnetic coupling mechanism. Basedon understanding intermolecular magnetic coupling mechanism, the novel radicalcomplexes have been synthesized with mnt as ligand and the relevant magneticcoupling mechanism have been studied.In this dissertation, six novel complexes have been designed and synthesizedwith mnt as ligand and with N-hydrogen pyridine cation, N-methylpyridine cation,N-ethylpyridine cation as counter cations, respectively, and with NiIII, PdIIIand CoIIIas central ion or coordinated metal ions, respectively. These complexes includemononuclear NiIIIcomplex [N-H-Py][Ni(mnt)2](1), mononuclear NiIIIcomplex[N-Methyl-Pyridine)][Ni(mnt)2](2), mononuclear NiIII[N-Ethyl-Pyridine][Ni(mnt)2](3), mononuclear PdIIIcomplex [N-H-Py][Pd(mnt)2](4). mononuclear CoIIIcomplex[N-Methyl-Py][Co(mnt)2](5), mononuclear CoIIIcomplex[N-Ethyl-Pyridine][Co(mnt)2](6). Infra-red spectra have been made on these sixcomplexes and the crystal structures have been determinate on the sixcomplexes by X-ray crystallography. Their crystal structures indicated that thereare different kinds of π-πstacking interactions between coordinated anions.Theoretical calculations have been performed on the π-πstacking interactions,which are based on the models that come from crystal structures. Thecalculations gave the information of the relevant magnetic coupling signs and the relevant coupling strengths of the π-πstacking models. The variable-temperaturemagnetic susceptibilities have been made for complexes (1), complex (2) andcomplex (3), and the magneto-structural correlations have been explored basedon the crystal π-πstacking data, the experimental magnetic data and thetheoretical calculation results. ESR spectra have been made for complex (4) andthe relevant magneto-structural correlation has been studies based on the esrdata and the coordinated anion π-πstacking interaction. The obtained studiedresults of this dissertation further confirm that the magnetic coupling strength ofπ-πstacking interaction is relevant to the spin densities of short contact atoms ofπ-πstacking system and is also relevant to the distance of the short contact atoms.This dissertation will benefit to prepare ideal molecule-based magnets andmagnetic equipment.