Synthesis And Properties Of Low-Symmetric Complexes Based On Thiazolidine2,4-Dicaboxylic Acid

Low-symmetric multifunctional complexes with helical structures and accessiblechiral properties have drawn extensive attention due to their potential for ferroelectricmaterials, enantioselective separations and second-order nonlinear optical （NLO）materials. Recently, with the miniaturization trend in device size, synthesis of crystalsin micron-nano scale becomes a significant direction of the development incoordination chemistry. Design and preparation of low-symmetric multifunctionalcomplexes and their corresponding micro-nano crystals with controllable structureshave offered remarkable prospects for application as functional molecular materials,which lead to great challenges as well.In this dissertation, based on the ligand thiazolidine2,4-dicaboxlic acid （H₂L）,43bulk-and13micro-nano crystals of low-symmetric complexes have been synthesizedthrough rational selection of metal centers and control of reaction conditions. Themain contribution and highlight of this thesis are below:1. Based on transition metal centers,21bulk-and8micro-nano complexes havebeen synthesized. New structure recurrence phenomenon has been successfullyrealized through adjusting the reaction temperatures. A versatile synthetic method thatrelies on surfactant has been presented, which goes beyond the traditional practice torealize conformational conversion of helical structures and dimensionaltransformation.2. Based on lanthanide metal centers,16bulk-and1micro-nano low symmetriccomplexes have been synthesized. Structure conversion behaviors have been realizedthrough changing the anion ions. The important size-effect on luminescence life-timehas been found to extremely prolong the life-time.3. Based on main group and d¹⁰metal centers,6bulk-and4micro-nano lowsymmetric complexes have been synthesized. Hierarchical hollow sphericalmetal-organic frameworks （MOFs） have been synthesized through a facilemicroemulsion method for the first time. Pores with different sizes exist in a singleMOF, including macropores, mesopores and micropores. Separation of two crystals with extremely similar properties has been achieved throuth this method as well. Inadition, chiral and NLO properties of the products have been measured.