Synthesis, crystal structure and properties of Mn/Ni/Co 3D network structures based on 2, 5-bis(trifluoromethyl) terephthalic acid ligands

Abstract

2,5-bis(trifluoromethyl)terephthalic acid (H2L1) as the main ligand and 1,10′-phenanthroline (L2) as the co-ligand were reacted with manganese chloride tetrahydrate (MnCl2·4H2O), nickel sulfate hexahydrate (NiSO4·6H2O) and cobalt nitrate hexahydrate (Co(NO3)2·6H2O) by solvothermal reaction to give the manganese complex [Mn2(L1) 2(L2)2]n (1), the nickel complex {[Ni3(L1)3(L2)2(H2O)4]·2DMF}n (2) and the cobalt complex {[Co2(L1)2(DMF)2]·H2O}n (3). The structures were characterized and their properties studied by means of single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, ultraviolet spectroscopy, fluorescence spectroscopy, thermogravimetric analysis. The single-crystal structure analysis showed that the complexes 1–3 are infinitely extended three-dimensional network-like structures of space groups P1-, P1-, P21/n, respectively. The results of fluorescence analysis and thermogravimetric analysis showed that complexes 1–3 have good thermal stability and fluorescence properties, respectively. Complex 3 can also maintain good thermal stability at 230 °C, and the maximum fluorescence emission wavelength is 370 nm.