Synthesis Of Manganese Complexes And Structural Characterization

Recently , the manganese complex with high ?spin electronic configuration as one of main fields of molecular magnetism shows a promising prospect . In this article ,novel manganese complexes with typical bridging ligands,bipyridyl similar and other ligands have been designed and synthesized . The growth of single crystals and their stuructural and magnetic characterization have also been proceeded Our main researching work has been focused on the study of manganese complexes with bipyridine ligands and carboxylate The concrete work is listed on the following paragraphs. (1) Five single crystals of manganese complexes are designed , synthesized and characterized by four梒ircle X ay single crystal diffraction .Crystal 1,3 and 4 crystallize in triclinic system , space group PT Crystal 5 crystallizes in monoclinic system , space group P2/c, with double bridge; Crystal 2 crystallizes in triclinic system , space group PT with extended linear chain one dimensional structure (2) Thermoanalysis Thermoanalysis was carried on crystal 1 and 2 . There are three turning points on TGA diagram and the characteristic temperatures of crystal 1 are 254.910C, 380. 13 , 596.430C.And it decomposes at characteristic temperatures . Therefore, crystal 1 is unstable when the temperature is higher than 210 0C. There are two turning points on TGA diagram and the characteristic temperatures of crystal 2 are 220.67 0C and 443. 96 0C . It decomposes at characteristic temperatures . Therefore, it is stable under 350 0C. But when the temperature is higher than 2100C , it tends to decompose (3)Eleetrochemical studies:Two acuminate reductive peaks and one oxidative peak which corresponds with one of the reductive peaks are on the cyclic voltammogram The carboxyls act as active group and the reversible redox are associated to them . The other reductive peak is attributed to the reductive action of the C bond (4) Magnetic study Crystal 2 is distinct extended linear hain one dimensional structure. Low temperature magnetic study is carried on it and it can act as molecular magnetism.(4) Comparative study on manganese crystals: We mainly synthesize the manganese complexes of low valence. The Mn ion is sixoordinate and is located in the center of the elongated octahedron .Coordinate atoms are N and 0. Phenathroline (phen) and 5, 5 - Me2 ipy are bidentate Nonor ligands and can form chelate structures. Carboxylato is 0onor lignd and can form double bridge or one dimensional structure as bridging ligand . Mn(II) can form mononuclear or binuclear complex and Mn(III) can form extended linear hain structure. Due to limited time , only some preliminary results are reported in this paper . It is because that these crystals have such fine properties , whose study of other distinct properties are presently underway.