Syntheses,Characterization And Property Studies Of Metal-organic Frameworks Constructed By Semi-rigid Polycarboxylic Acid Ligands

Metal-organic frameworks(MOFs)is a new type of porous crystalline materials,not only has the characteristics of large pore size,high porosity and surface,but also has the structures of novelty,diversity and thermal stability etc.The application of MOFs materials is very extensive and it has potential application in fluorescent sensing,gas adsorption,magnetic,electrical,heterogeneous catalysis.The design and synthesis of novel MOFs materials has become one of the hot spots in the field of modem scientific research.The selection of ligands and central metal ions is critical to the performance of MOFs.This paper chooses independent design and synthesis with semi-rigid polycarboxylic acid ligand to construct MOFs materials.The semi-rigid polycarboxylic acid ligands have the both advantages of rigid and flexible ligands,and poly carboxylic acid ligands possess different ability of deprotonation and diversity of coordination mode,it is available to construct novel structures of Metal-organic frameworks.This paper choose the semi-rigid organic ligand 4-(3,5-biscar-boxybenzyloxy)benzoic acid(H3L)as the main ligand,and select different length N-donor ligands 4,4'-Bipyridine(bpy),1,2-Bis(4-pyridyl)ethane(bpe),1,2-Bis(4-pyridyl)ethylene(bpee),N,N'-Bis(4-pyridylmethyl)piperazine(bpmp)as assist ligands to reaction with metal ions under hydrothermal conditions and obtain 15 coordination polymers with novel structure.Compounds {[Zn3(OH)(HL)L(H2O)3]·H2O}n(1),[Zn(HL)(bpy)H2O]n(2),{Zn1.5(bpe)0.5(L)(H2O)3]·H2O}n(3),{Zn2(bpee)0.5(L)(H2O)(OH)]·H2O}n4),{[Zn2(HL)L(H2O)]·(bpmp)0.5·H2O}n(5),[CoL(bpy)0.5(H2O)]·H2O(6),[Co1.5L(bpy)0.5(H2O)4]·2H2O(7),[CoL(bpe)]n(8),{[Co3(L)2(bpe)4(H2O)2]·7H2O}n(9),[Cu(H2L)2(bpe)]n(10),[Cu(HL)(bpe)]n(11),{[Ni2(HL)2(bpy)2(H2O)2]·4H2O}n(12),{[Ni1.5(L)(bpy)0.5(H2O)4]·3H2O}n(13),{[Ni1.5(L)(bpmp)(H2O)3]·5H2O}n(14),{[Mn1.5(L)(H2O)3]·H2O}n(15)were characterized by single-crystal X-ray diffraction.In addition,the 15 compounds were also characterized and properties tested by the powder XRD?IR?thermogravimetric analysis?element analysis and the fluorescence spectrophotometer.The fluorescence detection of compounds 1 and 3 were tested by the fluorescence quenching method.The compounds detect metal ions in aqueous solution and sense aromatic nitro explosives in DMF suspensions were also investigated.In addition,the suspension liquid of compounds 1 in water were used to sense antibiotics.It reveals that compounds 1 and 3 can sense metal ions Fe3+ in the aqueous solution well and they also have good detection for 2,4,6-Trinitrophenol(TNP)in DMF suspension.Moreover,the research results also shows that the suspension of compounds 1 can sensitive detect antibiotics in water.These results manifest that compounds 1 and 3 may be used as potential fluorescent sensor materials for detecting environmental pollutants.