Synthesis, Structure And Properties Of Novel Metal-carboxylate Coordination Polymers

As a newly-identified functional molecule-based materials, metal-organic coordination polymer (MOCP) has been a focus of material chemistry due to their flexible tailoring structures as well as their facile functionlizing properties. According to the principle of crystal engineering, it is possible to rational design and synthesis of coordination polymer crystalline materials with predetermined structure. At the same time, coordination polymers can be endowed with optics, electric, magnetism, enantioselective separation and catalysis by selecting functional metal ions and organic ligands with functional groups. As the properties of coordination polymers is determined by their components and framework topologies, the construction of coordination polymer with novel topologies has been received considerable attentions with the development of their potential applications. Various new organic molecules and methods are explored to synthesis of MOCPs. So far, a large number of MOCPs have been reported. However, the large majority of MOCPs have been constructed from the discrete SBUs with connectivities of three, four, six, such as triangular(CN=3), tetrahedral(CN=4), square(CN=4), octahedral(CN=6) and so on. There are extremely rare reports on MOCPs constructed from building units with coordination number higher than six or from infinite polymer chains. Furthermore, up to date, the synthesis of MOCPs has been mainly focused on MOCPs with uninodal net topology, while the chemistry, as well as the synthetic strategy toward MOCPs with mixed vertices has received much less attention. In this dissertation, we have focused our study on the influence of the changes caused by the metal ions, organic ligands, solvents and chiral complexes on the building blocks and the structure of MOCPs. In chapter two, four novel 3D MOCPs were prepared and structurally characterized. The solvothermal reactions of m-H2BDC ligand and transition metal ions Zn2+ and Co2+ yielded two three-dimensional (3D) coordination polymers [Zn3(m-BDC)4] ·2NH(CH3)2·2NH2(CH3)2(MOCP-CJ1) and [Co3(m-BDC)4]·H2O·2NH2(CH3)2(MOCP-CJ2). These two compounds are analogues and have a novel 8-connected body-centered cubic (bcu) topology based on the assembly of cubic-shaped secondary building blocks(SBU). In contrast to those previously reported structures constructed from linear p-BDC ligand, the V-shaped configuration of m-H2BDC ligand plays an important role in the formation of such a bcu net; When m-H2BDC ligand reacted with Zn2+ ions in the presence of Na+ ions, a heterometallic [ZnNa(m-BDC)2]·NH2(CH3)2 (MOCP-CJ3) was built from the primitive cubic (pcu) packing arrangement of infinite heterometallic M-O-C rods (M= Zn2+ and Na+). The protonated dimethylamine cations, produced from the decomposition of DMF solvents under the solvothermal conditions, plays a templating role in the crystallization of MOCP-CJ3; we also prepared a 3D structure of [Cd3(m-BDC)4]?2NH2(CH3)2(MOCP-CJ4) formed by the hexagonal (hex) packing arrangement of infinited Cd-O-Cd rods. In chapter three, we investigated the effects of mixed solvents of DMF/HAc and the molar ratio of organic ligands and metal salts on the structure of MOCP. Sixcoordination polymers have been successfully synthesized and characterized by single crystal X-ray diffraction. When the molar ratio of organic ligands and metal salts is equal to 1:1, the solvothermal reaction of BTC ligands and transition metal ions Zn2+ and Co2+ gave a 3D framework of [HZn3(OH)(BTC)2(2H2O)(DMF)]·H2O (MOCP-CJ5) with (6,3)-connected network topology built from trigonal prism SBU and triangular linkers and a 2D framework of [Co6(BTC)2(HCOO)6(DMF)6] (MOCP-CJ7) constructed from hexagonal SBU and triangular building blocks, respectively; Using o-H2BTC as ligand, a 3D diamond-type framework of [Co18(HCOO)36]·3H2O(MOCP-CJ8) was obtained based on the assembly of CoCo4 tetrahedra; Without HoAc, the solvothermal reaction of BTC ligands and Zn2+ ions yielded a 3D framework of [Zn(BTC)]·NH2(CH3)2·DMF (MOCP-CJ6) with (6,3)-connected rutile net topology. When the molar ratio of the ligand and the metal salts was changed, the reaction of H3BTC and Cd2+ gave two 3D novel metal-carboxylates [Cd4(BTC)3(H2O)]?H2O? NH2(CH3)2(MOCP-CJ9) and [Cd5(BTC)4(Ac)(DMF)2]?3NH2(CH3)2(MOCP-CJ10). MOCP-CJ9 exhibits a (3,9)-connected framework topology built from novel 9-coordinated SBU and triangular linkers. MOCP-CJ10 has a (3,12)-connected net topology constructed from novel 12-coordinated SBUs and triangular linkers. In chapter four, Using the racemic mixture of chiral [CoIIIen3]Cl3 as the structure-directing agent, three novel metal-carboxylates have been prepared and structurally characterized. At relatively higher temperature, the metal complex [CoIIIen3]Cl3 has been fully decomposed. However, two 3D novel MOCPs were obtained. One is a 3D heterometallic framework of [CdCo(BTC)2]?2NH2(CH3)2? 2DMF (MOCP-CJ11) constructed from octahedral and triangular building uints. Another one [H2Cd4(BTC)4(DMF)]?2NH2(CH3)2?2H2O (MOCP-CJ12) exemplified the first ternary net with (6,3)-connected framework topology based on the assemblyof three different building block (triangular, octahedral and trigonal prism SBU). At lower temperature, we obtained a one-dimensional coordination polymeric chain containing the racemic mixture of chiral metal complexes. In chapter five, by choosing m-H2BDC or p-H2BDC as ditopic ligand, we prepared four metal-carboxylates under mild conditions The solvothermal reactions of m-H2BDC ligand and transition metal ions Ni2+and Zn2+ yielded two 3D supramolecular coordination polymer [Ni(m-BDC)(Py)3]·H2O (MOCP-CJ14) and [Zn(m-BDC)(Py)(DMA)] (MOCP-CJ15) constructed from 1D coordination polymeric chains by weaker intermolecular interactions. Solvothermal reactions of linear p-H2BDC or bpdc ligand with transition metal ions gave two unique 36 teselled 2D nework [Zn3(1,4-BDC)3Py2]?2(1,4-dioxane) (MOCP-CJ16) 和[Cd3(1,4-bpdc)3 (H2O)2] (MOCP-CJ17). Furthermore, MOCP-CJ16 can form a 3D novel supramolecular network with hexagonal (hex) lattice topology by using π-πpacking interaction. The linear configuration of p-H2BDC ligand plays an important role in the formation of such a 36 teselled 2D nework. The effect of the special configuration of organic ligand on the polymeric topology provides some value experimental facts for the rational design and synthesis of desired network.