Crystal Engineering Of Polyoxometalate And Cu(I)-N-Heterocycle Complexes

The researches of metal-organic coordination compounds have attracted considerable attention, due to their intriguing architectures as well as excellent properties. By using the principle and method of crystal engineering, one effective approach for the synthesis of novel hybrids is the incorporation of secondary building units (SBUs) with special components and properties, which can afford a synergic effect. Polyoxometalates (POMs), as a unique class of inorganic metal oxide clusters with unmatched structural versatility, abundant components and outstanding properties, such as catalysis, medicine and magnetism, which represent a significant type of candidates of SBUs for the construction of new hybrid materials with intriguing architectures and excellent properties.From the starting point of the synthesis of new POM-based metal-organic coordination compounds with intriguing architectures and excellent properties, this thesis works on the selection and utilization of different types of POMs and ligands to construct crystal products, investigating their structural difference. Herein, nineteen POM-based metal-organic coordination compounds were hydrothermally synthesized by using the classical Keggin and Lindqvist types POMs as the secondary building blocks to react with copper and N-heterocyclic ligands, and characterized by elemental analysis, IR spectroscopy, PXRD, XPS, TGA and X-ray crystallography. In addition, the electrochemical properties and the surface photovoltaic responses for some of these compounds were also studied.1. Seven POM-based metal-organic coordination compounds with extended structures were synthesized by using the classical Keggin and Lindqvist type POMs as the multi-dentate ligands to link copper and L1 (1,4-bis(pyrazol-1-ylmethyl)benzene) complexes, and the influence of reaction conditions on the compound structures were also investigated. Compounds 1 and 2 were synthesized at 150℃and they were isomorphous, in which L1 ligands bridge Cu(I) ions generating a cationic 2D 63 (hcb) skeleton. Furthermore, the [PW12O40]3- or [PMo12O40]3- anions fill into the cavity and serve as bidentate ligands to coordinate with the cationic skeleton forming a neutral 2D network with Schlafli symbol of (53)2(54;82). Compound 3 was synthesized at a relative lower reaction temperature (130℃) than that for the synthesis of 1, which exhibits a similar 2D sheet cationic skeleton with 1 and 2. Interestingly, the POM anions do not coordinate with the cationic moieties in 3. Compound 4 was synthesized with relative smaller amounts of copper dinitrate and L1 reactants in comparison with that for the synthesis of 3, in which the cationic coordination moieties all present 1D chain-like structure. Compound 4 exhibits a 3D (3,4)-connected sqc74 framework with Schlafli symbol of (6;82)(64;8;10). Compounds 5 and 6 were prepared by using [BW12O40]5-anions as reactant at different pH conditions (2.0 for 5 and 3.5 for 6, respectively), which both exhibit 2D structures, however, in 5 the protonated [HL1]+ species are observed, in 6 they are not present. Compound 7 consists of Lindqvist type [Mo6O19]2-anions with two negative charges linking zigzag-type cationic chains to construct a 2D neutral wall-like network.[Cu3I(L1)4][PW12O40] (1)[Cu3I(L1)4][PMo12O40] (2) [Cu3I(L1)4][PW12O40] (3)[Cu3I(L1)3][PW12O40] (4)[Cu4I(L1)5(HL1)][BW12O40] (5)[Cu5I(L1)5][BW12O40] (6)[Cu2I(L1)2][Mo6O19] (7)2. Six POM-based metal-organic supramolecular compounds were synthesized by using Keggin type POMs as the template, in which the cationic moieties possess dimension limited macrocycles or rod-like structures. In compound 8 the [PMo12O40]3-anions with three negative charges act as the template directing L ligands to link Cu(I) ions forming an interesting triangular [3+3] type macrocycles. Compounds 9-11 are crystallographically isomorphous, and they contain [SiMo12O40]4-, [SiW12O40]4-, and [GeMo12O40]4- anions with four negative charges as the templates, respectively, to build up the square [4+4] type cationic macrocyclic structures. In comparison with the in suit synthesized compounds 8-11, compounds 12 and 13 were synthesized by utilizing [SiMo12O40]4- and [BW12O40]5- anions as the reactants, respectively, and at lower pH value conditions. The cationic moieties of 12 and 13 both possess OD rod-like structures, and interestingly, the lengths of these protonated cationic rods are controlled by the charges of POM anions.[Cu3I(L1)3]2[PMo12O40]2 (8)[Cu4I(L1)4][SiMo12O40] (9)[Cu4I(L1)4][SiW12O40] (10)[Cu4I(L1)4][GeMo12O40] (11)[Cu2IL1(HL1)2][SiMo12O40] (12)[Cu8I(L1)7(HL1)2][BW12O40]2 (13)3. Six POM-based metal-organic coordination compounds were built up by Keggin type POMs, Cu(I) cations and L2 (4,4'-bis(pyrazol-1-ylmethyl)biphenyl) or L3 (4,4'-bis(imidazolyl- 1-ylmethyl)biphenyl) ligands. Interestingly, compounds 14 and 15 have the same unit cell parameters but with different crystal structures. In 14, the L2 molecules link Cu(I) cations to form a helical chain structure with the inside diameter about 3 A, however, in 15 the L3 molecules bridge Cu(I) cations to form a more big helical chain in which the inside dimeter achieve 19 A. Compounds 16 and 17 were prepared by using [SiW12O40]4- anions as reactants at different pH conditions (3.5 for 16 and 2.0 for 17, respectively), in which the square [4+4] type macrocyclic and chain-like cationic structures were found, respectively. Compounds 18 and 19 were synthesized at different conditions but with isomorphous structures, in which the cantionic moieties exhibit pearl necklace structures. In 18, the H3PW12O40 are used as the reactant, however, the sodium molybdate and phosphoric acid are used to in suit synthesis of compound 19.[Cu3I(L2)3][PMo12O40] (14)[Cu3I(L3)3][PMo12O40] (15)[Cu4I(L2)4][SiW12O40]·CH3CH2OH (16)[Cu4I(L2)4][SiW12O40] (17)[Cu3I(L2)4][PW12O40] (18)[Cu3I(L2)4][PMo12O40] (19)...