Design, Assembly And Crystal Structures Of Novel Coordination Polymers Of Transition Metal-azaaromatic Ligands

In this dissertation, based on the coordination bond and the other intermolecular interaction such as hydrogen bonding, a series of one dimensional (1-D), two dimensional (2-D) and three dimensional (3-D) coordination polymers have been designed in the principle of crystal engineering and synthesized by means of hydrothermal or homogeneous reactions. By comparison of some related crystal data from the Cambridge Structural Database (CSD), some internal causes of reactions have been explored.1. In chapter 1, the factors regulating the structure of coordination polymer are concisely outlined, and the recent progress of the related to our azaaromatic ligands in the field of coordination polymer is also briefly reviewed.2. Some crystal structures of novel supramolecular aggregates have been obtained by means of the hydrogen bonding interaction between small coordination units and water molecules.(1). A novel supramolecular aggregate, [Cu(H₂bpdc)(NO₃)(H₂O) Cl]₂ (bpdc denotes 2,2'-bipyridine-4,4'-dicarboxylic acid), has been constructed by means of the hydrogen bonding interaction between two H₂bpdc molecules, and between small coordination units and water molecules under the condition of nitric acid. In this complex, water molecule, chloride ion, and nitrate ion which possess different coordination ability can coordinate the same Cu(â…¡) ion. This is rare according to the data index from CSD.(2). Two isomeric supramolecular aggregates, [Co(bpp)₂(H₂O)] (1,5-nds)·2H₂O and [Co(bpp)₂(H₂O)](2,6-nds)·2H₂O, have been prepared by means of the hydrogen bonding interaction between water molecules and 1,5-nds or 2,6-nds. bpp denotes the central ligand of l,3-bis(4'-pyridyl)propane with a flexible spacer between its two pyridine rings, and 1,5-nds or 2,6-nds denotes 1,5-naphthalene or 2,6-naphthalene disulfonate dianions, respectively, which their sulfate anions have weak coordination ability. The complex [Co(bpp)₂(H₂O)] (1,5-nds)·2H₂O is linked into 3D structure through hydrogen bond interactions, while the structure of complex is a 2D layer network. The result indicates that the big anion can balance the charge of the whole structure, and it can also affect notably the structure of network.3. Five supramolecular aggregates, {[Ag(bpp)]·0.5(1,5-nds)·H₂O}_n, {[Ni(bpp)₂(H₂O)₂]·(1,5-nds)}_n, {[Zn(bpp)(2,6-nds)(H₂O)₂]·2H₂O}_n, {[Co(bpy)(H₂O)₄]·(1,5-nds)}_n and {[Co(bpy)₂(H₂O)₄][Co(bpy) (H₂O)₄]·(2,6-nds)₂·2H₂O}n have been prepared, where bpy is 4,4'-bipyridine. Among the five crystal structure except Zn-bpp-(2,6-nds), the coordinated water molecules act as donor of hydrogen bond and nds act as acceptor.(1). In the coordination polymer {[Zn(bpp)(2,6-nds)(H₂O)₂]·2H₂O}_n, Zn(â…¡) coordinates O atoms of 2,6-naphthalene disulfonate dianions with Zn-0 bond length ca. 2.2 A. This is the first case of coordination between Zn(â…¡) and naphthalene disulfonate based on the index from CSD. According to our cases and the data index from CSD, for a linear coordination metal ions, a 1D sinusoidal structure can be obtained easily when the ligand is bpp with a flexible spacer. For octahedron coordination metal ions such as Ni(â…¡), Co(â…¡) and Cd(â…¡), a 1D duplex structure can be obtained easily. All these 1D structures can be further linked into 3D structures by means of hydrogen bonding interaction between their coordinated waters and naphthalene disulfonate dianions.(2). As a control, two coordination polymers {[Co(bpy)(H₂O)₄]·(1,5-nds)}_n and {[Co(bpy)₂(H₂O)₄]·[Co(bpy)(_H2O)₄]·(2,6-nds)₂·2H₂O}_n from a rigid ligand bpy can be obtained. Based on the two complexes and the data index from CSD, 1D linear coordination structure is still kept after the flexible ligand bpp is replaced by rigid ligand bpy. Similarly, naphthalene disulfonate dianions can act as a hydrogen bond bridging these 1D linear polymeric strands.In the structure of {[Co(bpy)₂(H₂O)₄]·[Co(bpy)(H₂O)₄]·(2,6-nds)₂·2H₂O}_n, a 2D layer structure from one coordination unit can be formed by hydrogen bond between the water molecules and sulfate, which the depth is ca. 23 A. On the both sides of the layer structure, it consists of two types of acceptors of hydrogen bond from uncoordinated N atoms of bpy and O atoms of sulfate. The 3D structure can be formed by means of this bilayer acceptors and coordinated water molecules of other 1D Co (II) coordination polymers. This novel assembly style has not been reported in previous researches.4. Two novel coordination polymers [Zn(bpp)(tda)₂(H₂O)]_n and [Ni(bpp)(tda)(H₂O)₂]_n have been obtained, which tda is thiophene-2,5-dicarboxylic dianions.(1). In the structure of [Zn(bpp)(tda)₂(H₂O)]_n, the coordination mode of Zn(II) is tetrahedral, which its one site is occupied by one water molecule. The hydrogen bonds between water molecules and carbonyl O atoms play an important role in the aspect of interpenetration. From the topological point of view, because each Zn(II) acts as a T type three-connected center, [Zn(bpp)(tda)₂(H₂O)]_n is the first example of eightfold interpenetration of (10,3)-b (ThSi₂) nets.(2). In the structure of [Ni(bpp)(tda)(H₂O)₂]_n, the coordination mode of Ni(â…¡) is a distorted octahedral geometry, which its two sites are occupied by two water molecule. The structure of [Ni(bpp)(tda)(H₂O)2]_n belongs to an interesting two-dimensional grid-type bilayer running parallel to (001) plane, and the bilayer is formed through intermolecular O-H...O hydrogen bonds. The topological property of [Ni(bpp)(tda)(H₂O₎2]_n is a general (4,4) net when each Ni(â…¡) acts as node.In this structure, the more remarkable structural character is that the H-O-H...Ï€interaction between water molecule and aromatic ring is directly found. This is the first observation in the crystal of small molecule. It provides a base of structural chemistry for more precise quantum mechanics calculation.5. Three isostructural 3D coordination polymers {[Co(bpp)₂Cl₂]·(CH₃CH₂OH)·(CH₃OH)·1.5H₂O}_n, {[Cu(bpp)₂Cl₂]·2.5H₂O}_n and {[Cd(bpp)₂Cl₂]·2.5H₂O}_n were prepared. All these structures contain two equal coordination units. The total topological property is a fourfold interpenetration of 66 diamond type, and there exist ca. 26% void volume in their cells with infilling of solvent molecules.6. Using 2,2'-dithiobipyridine (ps-sp) instead of bpp, we tried to synthesize some novel copper(I) complexes that 2,2'-dithiobipyridine can coordinate metal ion with N atoms of pyridine and S atoms of its spacer. The disulfide bond was broken during hydrothermal synthesis, and a hexanucleic cluster Cu₆-(ps)₆ including Cu(I)-Cu(I) metal bonds was obtained. A radical mechanism has been given to explain this phenomenon of disulfide bond cleavage.Totally, here the 14 crystal structure include 3D coordination polymer and supramolecular aggregates by hydrogen bond interactions between water molecules and small coordination unit, 1D coordination polymer strand, 2D and 3D polymer networks.