Synthese, Crystal Structures And Properties Of Metal-Organic Frameworks Based On Biphenyl-3,3’,5,5’-tetra-(Phenyl-4-Carboxylic Acid) Ligand

In this thesis, primary tetra-carboxylate-acid ligand of biphenyl-3,3’,5,5’-tetra-(phenyl-4-carboxylic acid (H4L) was used to synthesize a series of metal-organic framworks (MOFs) with transition metal ions, lanthanide metal ions and main-group metal ion by solvothermal condition. Charcterization about structures and photoluminescence properties have been processed.1. Based on biphenyl-3,3’,5,5’-tetra-(phenyl-4-carboxylic acid), six transition metal-MOFs are synthesized:[Zn2(L)(H2O)]·17H2O·DMF (1), [Zn2(L)(bpp)2]·3DMF(2), [Zn2(L)(tda)(H2O)]·4DMF·2MeNH2+(3), [Cd2(L)(H2O)4]·18H2O·DMF (4), [Cd4(L)2(H2O)2(bpp)2(Py)(DMF)]·30H2O·8DMF (5), [Cu2(L)(H2O)]·14H2O·DMF (6).1,3,4,5 and 6 are all microporous three-dimension MOFs,2 is 2D ladder architecture and further linked into 3D architecture by hydrogen bonds. The photoluminescence studies of MOFs revealed that the main emission bands are similar to that of H4L, but obvious blue-shifted bands occur.2. Biphenyl-3,3’5,5’-tetra-(phenyl-4-carboxylic acid) was used to synthesize seven microporous Ln-MOFs:[Ln3(L)2(H2O)7]·nDMA (Ln = Gd (7), n=10; Dy (8), n=10; Ho (9) n=15); [Ln3(L)2(H2O)3]·nDMA (Er (10), n=10; Tm (11), n=0; Yb (12), n=11; Lu (13) n=12). Single-crystal X-ray diffraction reveals 7-9 belong to orthorhombic crystal system, Ccca space group, and 10-13 belong to monoclinic crystal system, C2/c space group. Part of the MOFs showed characteristic fluorescence characteristics of lanthanide metals. And we adopted with different solvents to 12 to modificated covalent, studying the changes of fluorescence peak position and intensity.3. Biphenyl-3,3’,5,5’-tetra-(phenyl-4-carboxylic acid) and Ba(Ⅱ) was used to synthesize a Ba-MOF:[Bas(L)3(HO)6]-25H2O·10DMF-2Me2NH2+(14).14 belongs to the hexagonal space group P6/m. Single-crystal X-ray diffraction reveals its three-dimensional structure, in which the open channels are occupied by free solvents and counterions (Me)2NH2+. Meanwhile,14 shows potential sensors for small molecule, such as organic solvents, Metal salt solvents. On the other hand, nitroaromatics such as nitrobenzene 1,3-DNB (1,3-dinitrobenzene) significantly enhanced or quenched the emission.