Design, Synthesis And Crystal Structures Of Functional Bispyrazole Complexes

Recent developments in the research for optoelectric functional complexes and bispyrazole methane complexes were reviewed based on a great deal of related literatures. A series of novel functional their metal complexes were designed and synthesized which are presented as follows;1. With aid of Friedel-Crafts Alkylation, Ullmann, Wittig reaction and reaction of aldehyde with 1, 1'-sulfinyldipyrazole, four novel ligands were successfully synthesized, which were 3,6-di-tert-butyl-9-(4-(di(1H-pyrazol-1-yl)methyl) phenyl)-9H-carbazole(L1),1,1'-(anthracen-9-ylmethylene)bis(1H-pyrazole) (L2), 9-(4-(di(1H-pyrazol-l-yl)methyl)phenyl)-9H-carbazole (L3) and (E)-1,1'-((4-(2-(anthracen-9-yl)vinyl)phenyl)methylene)bis(1H-pyrazole) (L4). All the four bispyrazole methane ligands were characterized by IR,1H NMR, and MS spectra. In addition, ligand L2 was structurally characterized by single-crystal X-ray diffraction analysis. The optical properties of the four ligands were investigated, such as UV-vis, single-photon induced fluorescence. The transitions were assigned further according to theoretical calculation. The results showed that L2, L4 emitted in the visible range, the fluorescent quantum yield of L2 was up to 0.76;2. Fourteen complexes were obtained by reacting L1, L2, L3, L4 with ZnCl2, ZnBr2, ZnI2 and reacting L2, L3 with Cu(ClO4)2.6H2O, all of them were characterized by IR and elemental analysises. L2 and its ZnCl2, ZnBr2, ZnI2, Cu(ClO4)2 complexes were also characterized by single crystal X-ray diffraction analysis. The results of crystal structure analysis showed that complex [ZnCl2L2]2 with chloro-bridged dinuclear zinc, crystallized in monoclinic system and P21/c space group, in which Zn(II) ion was coordinated with five atoms, they formed distorted square pyramidal geometry. Although the coordination mode chloro-bridged was common in the other ZnCl2 complexes, the coordination mode in the bispyrazole ZnCl2 complexes was firstly reported. The complexes ZnBr2L2 and ZnI2L2 with mononuclear zinc, crystallized in Monoclinic system, P21/n space group, in which Zn(II) ion was in distorted tetrahedron coordination; The complex Cu(L2)2(ClO4)2.2CH3CN with mononuclear copper, crystallized in triclinic system, P1- space group, in which Cu(II) ion was six coordinated forming an octahedron. There were two solvent acetonitrile molecules in a unit cell. It is scarcely reported that ClO4- ions as a ligand coordinate to Cu(II) ion, the Jahn-Teller effect is very obviously observed in Cu(L2)2(ClO4)2.2CH3CN, the distance of Cu-O bond was longer than that of Cu-N bond, ClO4- could be easily replaced by other groups, so it presented a structural clue for the further assembly;3. Emission spectra of L2 and its Zn(II)complexes in solid state were investigated, TGA of L2 and Cu(L2)2(ClO4)2, ESR of Cu(L2)2(C104)2 and Cu(L3)2(C104)2 were finished. The results showed that emission spectra of ZnBr2L2 in solid state displayed single-color emission, the others displayed two-color emission, the intensity of ZnBr2L2 was the strongest; The results of TGA showed that ligand L2 decomposed slowly, but complex Cu(L2)2(ClO4)2 had a dramatic weight loss when the coordinated L2 decomposed in the range of 20℃, energy was released in short time; ESR spectra showed that Cu(ClO4)2 complexes of L2 and L3 were six-coordinated, the bond distance of Z axis was more longer than that of X and Y axis, the Jahn-Teller effect was obviously observed, it was demonstrated that Cu(II) ion coordinated with ClO4- in Cu(L2)2(ClO4)2 and Cu(L3)2(ClO4)2 complexes were further characterized by ESR spectra.