| Open-framework materials have been extensively studied in the past decades due to their architecture, structure diversity and functional properties. Among these, micriporous compounds based on the MO4 (M=Si, Al, P etc.) are ones of the most important and known, which have been found to be useful in the industrial catalysis, gas adsorption and separation. The synthesis of new open-framework compounds is the first step to their applications. Metal phosphates and sulfates constructed from the PO4 tetrahdra and SO4 tetrahedra, respectively, are the important members of the open-framework materials. In this thesis, several indium phosphates, transition metal sulfates and rare earth sulfates were solvothermally synthesized by using different organic amines as structure directing agents (SDAs) in the mixed solvents. The compounds were characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectrum and thermogravicm analysis, etc. The chirality, magnetic properties, ferroelectricity and dielectricity of some compounds were studied. The thesis was divided into the following five chapters.Chapter 1, Introduction. A brief introduction of the definition, history and recent developments of microporous open-framework compounds were presented. Some extra-large pore open-framework materials were selected as examples to discuss their synthesis strategies. The challenge and opportunity of such compounds were also outlined. The goal and method of this work were dissertated at the end of this chapter. Chapter 2, Synthesis of Five Indium Phosphates Compounds with Open-Framework:[NH4][In(HPO4)2] (1); [NH4][In(OH)PO4] (2); [NH4]4[In8(HPO4)14(H2O)6] (3); [(C6H18N2)(H2O)][In2(OH)(HPO4)2(PO4)] (4); [(C2N2H10)(H30)(H20)2][In3(HP04)6] (5).1 was synthesized in the mixed solvent of water and ethylene glycol with triethyleneamine as SDAs, while 2 was obtained in the occurred of HF with 1,3-propenediamine(1,3-PDA) as SDAs by hydrothermal method. Both 1 and 2 were three-dimensional framework chiral compounds with a set of helix channels along the [011] and [0-11] directions, respectively, to construct an intersecting 8-MR pore in 1, and a cis-helix chain within the intersecting 8-MR pores in 2. The charility of 1 and 2 were confirmed by the Vibrational Circular Dichroism (VCD).3-5 were solvothermally synthesized in the solvents of water and EG with different amines 1,3-PDA,2-methyl-pentamethylenediamine (MPMD) and diethylenetriamine (DETA) as SDAs, respectively. The 3-D framework of 3 was constructed from the layers pillared by InO6 octahedra to form a 12-MR open channel along the a-axis where the NH4+ cations locate. The 2-D layered structure of 4 contains face-shared 3-MR and 5-MR. The diprotonated MPMD molecules locate between the layers to balance the framework charges and stabilize the framework by forming extensive hydrogen bond interactions. The 3-D framework of 5 were constructed from the [3,3,3] propellane-like second building units (SBU) to form intersecting 12-MR channels along the [110] and [-110] directions, where the protonated water and ethylenediamine derivated from EDTA locate.Chapter 3, Synthesis and Properties of Nine Transition Metal Sulfates:NH4 MSO4F (M= Mn,6; Fe,7; Co,8; Ni,9); [C2H6O2]Mn2(SO4)2 (10); [C4N2H12]2[(C2H4O2)Fe3F2(SO4)4] (11); [(NH4)4][Co3F6(SO4)2] (12); [(NH4)4(SF6)][M3F6(SO4)2] (M=Co,13; Ni,14). The 3-D open-framework KTP-type compounds of 6-9 and 2-D layered Kagome-type compounds of 12 were synthesized in the solvent of N',N-dimethyleneacetamide (DMA) with the addition of different amouts of HF. The organic SDAs in these five compounds were NH4'cations derivated from the decomposition of the DMA molecules.10 and 11 were obtained in the solvent of EG with piperazine as SDAs without and with the addition of HF. The EG molecules were introduced into the 3-D open-framework manganese sulfate 10 and the 2-D layered iron sulfate 11. The isomorphous 13 and 14 were synthesized in the solvent of EG with 1,3-PDA used as SDAs but with only NH4+ cations and in situ formed SF6, molecules occluded in the products. Althoug 12,13,14 are 2-D Kagome type compounds,12 crystallizes in the C2/c group with a two-folded axis while 13,14 crystallize in R-3m group with a 3-folded axis. The magnetic studies showed that magnetic exchanges between the neighboring metal centers in 8 and 9 are both antiferromagnetic, while 13,14 exhibited canted antiferromagnetism.Chapter 4, Synthesis and Properties of Fourteen Rare Earth Sulfates: [C4N2H12]3[Ln3(OH)(SO4)7] (Ln=Pr,15; Nd,16; Sm,17; Eu,18; Gd,19; Tb,20; Dy, 21); [(C4N2H12)4(H2O)4][Ln4(H2O)4(SO4)10] (Ln=Gd,22; Eu,23); [NH4(C6N2H12)] [Ln(SO4)3] (Ln=Eu,24; Gd,25); [(C4N2H12)1.5][Er(SO4)3(H2O)] (26); [(NH4)3][Dy (SO4)3] (27); NH4[Er(SO4)2H2O] (28). The 3-D open-framework rare earth sulfates 15-21 with one dimensional 24-MR open channel were synthesized in the mixed solvent of water and ethanol with PIP as SDAs. All these seven compounds are isomorphous, and crystallize in the polar group of P31c. The ferroelectric studies of 16 and 17 showed the typical electric hysteresis loops of ferroelectricity, which was further confirmed by the dielectric data. All of the other four compounds of 22,23,26, 28 were obtained solveothermally from the mixed solvent of water and ethanol with PIP as SDAs.22,23 are isomorphous and possess a 3-D framework structure constructed from LnO8,9 polyhedra and SO4 tetrehedra with an intersecting 8-MR channel along the [001] direction.26 is a 1-D chained erbium sulfate with diprotonated PIP molecules located between chains, while 28 is a 3-D open-framework with ant-type topology templated by the NH4+ cations. The 2-D layerd structures of 24,25 were formed in the DMA solvent by using cyclic diamine as SDAs. The 2-D layered dysprosium sulfate 27 was also synthesized in the solvent of DMA without addition of organic amines as SDAs. The NH4+ cations derivated from the decomposition of DMA locate between the layers.Chapter 5, Conclusion and Outlook. The results of this thesis were summarized. Future work plan on these projects were also presented. |
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