Abstract
In this thesis, three organic-inorganic hybrid zinc compounds were synthesized via the hydrothermal method utilized by solvent reducing under a green chemistry concept . These three compounds used 2-aminoterephthalic acid (NH2BDC) and 3-Amino-2-naphthoic acid (NH2NC) as organic linkers to form one three-dimensional (3D) and two layered structures. The formulas are [Zn3(H2O)2(PO4)(HPO4)(NH2BDC)0.5]·0.5(1,6-dah)·2H2O (A1) (1,6-dah denoting for 1,6-diaminohexane), Zn2(PO4)(NH2BDC) (A2), and Zn(NH2NC)2 (A3), respectively, determined by single crystal X-ray diffraction. Both A1 and A2 comprise zinc phosphate (ZnPO) inorganic sheets with NH2BDC as an organic ligand. The ZnPO sheets of A1 are pillared by NH2BDC to form a 3D neutral framework templated with 1,6-dah and water. The ZnPO sheets of A2 are tri-dentated via the amine group and the carboxylate group on one side of NH2BDC and with the other side of carboxylic acid being pendant. The layers of A2 are stacked via hydrogen bonding in a cyclic dimer mode provided by the non-coordinating carboxylic acid groups of the adjacent layers. A3 is a zinc coordination polymer which contains ZnO4N2 octahedra interconnected by NH2NC to form a layered structure. The layers of A3 are packed by the Van der Waal force between benzene rings. As compared with zinc phosphates that incorporate organic aryl carboxylates prepared by our group previously which could sustain heating up to around 280 ºC, A2 has significant thermal stability up to 440 ºC confirmed by TGA and PXRD. The high thermal stability of A2 could be explained by four reasons：(1) the neutral framework of A2; (2) the tri-coordination of NH2BDC to three different zinc sites of the inorganic sheet; (3) the strong hydrogen bonding between the layers; (4) the sheets formed of zinc polyhedra without the phosphate group via edge and corner sharing, which are comparatively different from other zinc phosphates. With the exposed carboxylic acid group on the layer surface of A2, surface functionality has been successfully made to change its wettability from hydrophilic to hydrophobic by amidation. Whether the surface modification is a reversible process by thermal treatment or not depends on the amidation condition. In addition, A2 can also be transformed into blue-white fluorescent light material by intercalation of 4,4'-trimethylenedipyridine (TMDP). During the intercalation experiment, a zinc coordination polymer, Zn(NH2BDC)(TMDP) (A2-TMDP), was crystallized on the surface of A2. Those discoveries might bring a new prospective to the two dimensional inorganic-organic hybrid zinc phosphates.