| In recent years,switchable phase transition materials have aroused widespread attention as new functional materials.Organic-inorganic molecular-based hybrid compounds are the most suitable choices for preparing phase transition materials on account of their simple synthesis,adjustable structure,environmental protection,and flexibility,which makes them widely applied in data storage,signal processing,piezoelectric sensing,etc.However,designing switchable dielectric materials with high phase transition temperature is still a huge challenge.In this thesis,we designed and synthesized a series of organic-inorganic hybrid compounds with spirocyclic quaternary ammonium salts as cations and metal halides as anions by adjusting their molecular structures and molecular packing modes.A series of characterization methods were conducted to furture explore the structure of these compounds,whether the dielectric phase transitions occurred and the temperature of the phase transitions.This thesis is elaborated mainly from the following three sections:The first part expounds the hybrid compounds with spirocyclic piperidine quaternary ammonium salt as the cations,including[C10H20N]2[Cd Cl4](compound 1),[C10H20N]2[Mn Cl4](compound 2),[C10H20N]2[Zn Br4](compound 3),and[C10H20N]2[Mn Br4](compound 4).The second part states the hybrid compounds with spirocyclic morpholine quaternary ammonium salt as the cations,containing[C8H16NO]2[Cd Br4](compound 5),[C8H16NO]2[Mn Br4](compound 6),and[C8H16NO]3[Bi2Cl9]2(compound 7).The third part describes the hybrid compounds with spirocyclic morpholine derivative quaternary ammonium salt as the cations,including[C10H20NO]2[Cd Br4](compound 8),[C10H20NO]2[Zn Br4](compound 9),and[C10H20NO]2[Mn Br4](compound 10).Results show that hybrid compounds 1-4 with spirocyclic piperidine quaternary ammonium salts as cations have undergone high-temperature phase transitions,exhibiting excellent bistable dielectric switching characteristics.In addition,by modulating the anion combinations of the metal and halogen atoms,the phase transition temperature of the compounds can be adjusted.This discovery provides a new trail to discover high-performance phase transition materials. |
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