Study On The Synthesis And Properties Of Free-Radical Amine And Quasi-Spherical Phosphine Organic-Inorganic Hybrid Phase Change Materials

Phase change materials in the external conditions（such as temperature,pressure,illumination,electric field,magnetic field,etc.）stimulation could have the corresponding response,thus inducing solid-solid structure phase change,resulting in crystal structure changes,but also accompanied by DSC,dielectric constant,SHG signal,piezoelectric and ferroelectric and many other macro physical properties of the mutation.Therefore,they are widely used in the fields of supercapacitor,data storage,infrared detection,piezoelectric sensing,dielectric switch,second order nonlinear switch and so on.Organic-inorganic hybrid phase change materials have been highly expected due to their unique properties,which may replace inorganic phase change materials in the future,and are expected to become the key technologies in the fields of hermoelectric,photoelectric,thermochromic and photoluminescent devices.Thus,it has always been the persistent pursuit of material researchers to explore organic-inorganic hybrid phase change crystal materials with excellent properties through different methods.Based on the theory of"single chiral","quasi-spherical"and"momentum matching",we design and synthesize a series of new organic-inorganic hybrid crystals of free radical amines and quasi-spherical phosphines using the idea of chemical modification.The synthesis process,NMR,crystal structure,phase transition properties,dielectric properties,SHG effect and ferroelectric properties were studied.In the first part of this paper,TEMPO radical was modified by quaternization and the introduction of chiral groups,and two new free radical compounds[Me₃N-TEMPO]I and[Py-TEMPO]I were obtained,and reacted with Na Cl O₄,KPF₆,Cd I₂and Pb I₂,respectively.Six kinds of free-radical amine organic-inorganic hybrid compounds were synthesized:[Me₃N-TEMPO]Cl O₄（1）,[Me₃N-TEMPO]PF₆（2）,[Me₃N-TEMPO]NO₃（3）,[Py-TEMPO]Cl O₄（4）,[Py-TEMPO]₂Cd I₄（5）and[Py-TEMPO]Pb I₃（6）.Compound 3 has reversible phase transition and compounds 4,5and 6 crystallize in polar space group.In the second part,three supramolecular free radical compounds([（NH₃-TEMPO）（18-Crown-6）][PF₆]（7）,[（NH₃-TEMPO）（18-Crown-6）][As F₆]（8）and[（NH₃-TEMPO）（18-Crown-6）][Sb F₆]（9）were designed and synthesized.Compounds 7 and 8 are high temperature free radical ferroelectrics with high temperature reversible phase transition,dielectric bistable and SHG bistable phenomena,ferroelectric hysteresis loops and paramagnetism.In the third and fourth parts of our word,two phosphine small molecules[Me（Me₂N）₃P]I and[i-Py（Me₂N）₃P]I were synthesized by chemical modification of spherical molecules with methyl and isopropyl groups,and then reacted with inorganic salts and metal halides to obtain ten phosphine organic-inorganic hybrid crystals:[Me（Me₂N）₃P]Cl O₄（10）,[Me（Me₂N）₃P]PF₆（11）,[Me（Me₂N）₃P]Pb I₃（12）,[Me（Me₂N）₃P]₂Cd I₄（13）,[Me（Me₂N）₃P]Bi I₄（14）,[i-Pr（Me₂N）₃P]Cl O₄（15）,[i-Pr（Me₂N）₃P]PF₆（16）,[i-Pr（Me₂N）₃P]Pb I₃（17）,[i-Pr（Me₂N）₃P]₂Cd I₄（18）,[i-Pr（Me₂N）₃P]Bi I₄（19）.All compounds successfully underwent reversible phase transitions,and compounds 16 and 18 underwent two reversible phase transitions.Compounds 10,11,12,13,15,17,and 18 showed reversible SHG effects,and compound 18 underwent two reversible SHG mutations.The SHG abnormal temperatures of the compounds are basically consistent with the phase transition temperatures measured by DSC.Compounds 10 and 17 crystallized in the chiral polar space group P2₁3 and P6₃ in the room temperature phase and the low temperature phase,respectively,and compound 17 belonged to the ferroelectric space group,which is a potential ferroelectric material.