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Synthesis, Structure and Morphology Control of Inorganic Framework Solids

Author: SunJinYu
Tutor: ZhaoDongYuan
School: Fudan University
Course: Physical and chemical
Keywords: Coordination Polymers Inorganic Networks Crystal Structure Zeolite Molecular Seives Self-Assembly Carboxylate
CLC: O611
Type: PhD thesis
Year: 2004
Downloads: 878
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Abstract

Coordination polymer is one of the most attractive topics of current researches. Therefore, a large number of coordination polymers with various topologies, such as diamond and ReO3, have been prepared in recent years. Apart from their aesthetically attractive structures, their inherent architectures also offer the substances the potential applications in molecular adsorption, optical or electronic molecular devices and molecular magnets. In fact, the effort for construction of coordination polymers by design of new carboxylic ligands has been essentially forced by the desire for large-pore materials, however, structural diversities of carboxylate-based coordination polymers are limited. In this dissertation, we use staple benzenecarboxylic acids such as terephthalate, metaphthalate, isonicotinate etc. as the ligands to construct brand new coordination polymers with various framework structures. Our strategies are to choose metal ions with particular geometries, regulate the composition of media and introduce the mono-functional ligands into the reaction systems:In view of the particular coordination geometries of the complex In(CO2)4" and Sn(CO2)22-, the In(III) and Sn(IV) were used as central metal ions to react with terephthalate, metaphthalate and 4,4’-biphenyldicarboxylate in DMF, producing following coordination polymers: (i) H[In(p-BDC)2]1.5DMF-4H2O (MCF-1) with quartz topology, which pore size is calculated to be 7.8 A; (ii) H[In(BPC)2]4H2O, (MCF-2) with four-fold interpenetrated diamond-like networks , (iii) H[In(m-BDC)2]-1.0DMF 2H2O (MCF-3); (iv) MCF-4 ([Sn(p-BDC)(SO4) (H2O)]-0.8DMF). The fashion of inter-penetration in MCF-2 is different from the 1/n or 4, 4 mode reported previously. MCF-3 and MCF-4 show unusual 2-dimensional structures. These results have evidenced that the frameworks of the coordination polymers are related to the particular geometry of metal ions.Four novel frameworks of coordination polymers have been also prepared by reacting rare earth metal ions such as Nd3+, Ce4+ ,Yb3+ with poly-carboxylate ligand: (i) [Nd2(P-BDC)3(DMF)3]-2H20 (MCF-5); (ii) [Nd2(m-BDC)3(DMF)2]-2DMF (MCF-6); (iii) [Ce2(p-BDC)3(DMSO)2]-2NO3 (MCF-7); (iv) [Yb2(m-BDC)3(DMF) (H2O)]-3DMF(MCF-8), of which, MCF-7 shows Re03-like topological structure with binuclear Ce-ions as the framework nodes while MCF-5, MCF-6 and MCF-8 share same chain-unit that is made up of co-edge polyhedra of rare-earth ions. However, the different coordinated models of carboxylate to rare earth ion resulted in the MCF-5 of a dense phase coordination polymer, the MCF-6 of open framework with 10 A hexagonal channels, and the MCF-8 with three-fold helical structure. Therefore, it seems that the structures of carboxylate-based coordination polymers are much dependant on the diversities of coordinate fashions of carboxylate to metal ions.We also investigated the effect of solvents on the structures of carboxylate coordination polymers of transition metals. Fourteen coodination polymers have been successfully prepared. They exhibite structural varieties produced in different solvent systems, for example, MCF-9, (Zn(ISN)2-2H2O) with the a-quartz-like open framework is formed in DMSO(DMF), MCF-10, (Zn(ISN)2) with diamondoid framework can be formed in ethanol and CP-1, (Zn(ISN)2(H2O)4) of monomer is obtained in water by the reaction of isonicotinate with Zn2+ ion, MCF-13, (Zn4(u3-OH)2(r-DMSO)4(p-BDC)3) with ReO3-like framework is built up from bicubane tetranuclear zinc blocks in mixture DMSO-ethanol (1/2), MCF-18, ([Zn(p-BDC)(H2O)2]-2H2O) with double-chain units can be obtained in DMSO-H2O (2/3) system, and MCF-17, ([Zn(p-BDC)(Py)(H2O)]) with single-chain unit is formed in water, and so on. All of these results have shown that the structural varieties are mainly dependant on the nature of the solvents used.Imitating the pillared clay, we firstly explored the synthetic strategy of two-step method for preparing novel coordination polymers, for example, a layered coordination polymer Zn3(p-BDC)3(H2O)2]-4DMF (MCF-25) was used as a precursor to re

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