Synthesis,Structure And Properties Of Functional Coordination Polymers Constructed From Biphenyl Polycarboxylic Ligands And Transition Metals

In this thesis,biphenyl polycarboxylic acid derivatives including biphenyl-2,4,4’-tricarboxylic acid and 2-(4-carboxypyridin-3-yl)terephthalic acid were used as organic bridging ligands.A series of novel coordination polymers were synthesized by divalent transition metal ions.At the same time,the synthesis conditions and formation rules of these complexes were studied.The topological types of the coordination networks formed were analyzed.The influence of the geometry of the ligands and ancillary ligands on the whole structure were also investigated.The self-assembly principles of related complexs,the new types of topological structures,the internal relationship between topological types and structures,and the relationship between the structure and properties of new complexes were explored.Through hydrothermal synthesis technology,we synthesized fifteen new metal-organic coordination polymers and characterized them by elemental analysis,thermogravimetric analysis(TGA),infrared spectroscopy,X-ray powder diffraction,and X-ray single crystal diffraction.At the same time,the magnetic and photoluminescence properties of some complexes were also studied.1.Biphenyl-2,4,4’-tricarboxylic acid(H3btc)was selected as ligand to synthesize nine new coordination complexes,namely[Zn(H2btc)(phen)2][H2btc]·H2O(1),[M(H2btc)2(H2biim)2]{M=Co(2)and Cd(3)},[Ni(Hbtc)(phen)2(H2O)]·2H2O(4),[Cd2(μ4-btc)(μ2-Cl)(phen)2]n(5),[Ni3(μ4-btc)2(μ2-H2O)2(py)4(H2O)2]n2(6),{[Co3(μ4-btc)2(μ2-H2O)2(py)4(H2O)2]·(PY)2}n(7),{[Co3.5(μ6-btc)2(μ3-OH)(py)2(H2O)3]·H2O}n(8),and {[Pb3(μ6-btc)2(H2O)]·H2O}n(9).These complexes were easily generated by hydrothermal self-assembly method from the corresponding metal(Ⅱ)chlorides,H3btc,and various N-donor ancillary ligands(including 1,10-phenanthroline(phen),2,2’-biimidazole(H2biim),or pyridine(py)).The complexes 1-9 were characterized by IR spectroscopy,elemental,thermogravimetric,and single-crystal X-ray diffraction analyses.Their structure ranges from the intricate 3D metal-organic frameworks(MOFs)(6-9)to the 2D coordination polymer(5),and to the discrete OD monomers(1-4).Such structural diversity is guided by the type of metal(Ⅱ)node,formation of the deprotonation of biphenyl-2,4,4’-tricarboxylic acid,and kind of ancillary ligand.The structures of 1-4 are further extended[OD→2D(1)and OD→3D(2-4)]into various H-bonded networks.Both the supramolecular networks(in 1-4)and coordination networks(in 5-9)were studied based on topology.The results show that the complexes displayed different topology networks,such as 4,5L64(1),pcu(2 and 3),sxb(4).Hcb(5)and wei(6 and 7).The unique topology framework is defined in MOFs 8 and 9.The magnetic properties(for 6-8)and photolumimescence properties(for 1,3,5,and 9)were also studied and discussed.2.A novel flexible multifunctional building block(H3L)bearing picolimate and terephthalate functionalities was designed and applied for the hydrothermal self-assembly.And a series of coordination compounds were synthesized:[Co(H2L)2(H2O)2](10),[M(HL)(H20)]n{M= Cd(11)and Mn(12)},{[Mn1.5(L)(phen)(H2O)2]·H2O}n(13),[Zn3(L)2(H20)6]n(14),and{[Zn3(L)2(py)(H2O)4]·4H2O}n(15){wherein H3L=2-(4-carboxypyridin-3-yl)terephthalic acid,phen= 1,10-phenanthroline,py=pyridine}.All the obtained complexes 10-15 were fully characterized by IR spectroscopy,elemental,thermogravimetric,powder and single-crystal X-ray diffraction analyses.By adjusting the molar ratio of NaOH and H3L ligand,partially deprotonated to form the H2L-blocks in 10,HL2-moieties in 11 and 12,or completely deprotonated to create the L3-units in 13-15 were formed.The structure ranges of the obtained complexes were from a discrete OD monomer(10)to ID coordination polymers(13 and 14),to 2D coordination polymers(11 and 12),and to an intricate 3D metal-organic framework(15).The corresponding topological classifications were also performed.The structures of 10-14 are further extended[0D→3D(10),ID→3D(13,14),and 2D→3D(11,12)]into supramolecular networks by means of multiple hydrogen bonds.The results revealed that the nature of metal(Ⅱ)ions,the molar ratio between NaOH and H3L ligand,and the presence(optional)of ancillary ligand played a significant role in determining dimensionality,topology and other structural features of the obtained complexes.Magnetic susceptibility measurements indicated that complexes 12 and 13 had dominating antiferromagnetic couplings between metal centers.Furthermore,the photoluminescence properties of 11,14,and 15 were also investigated.