The Study About Dielectric Properties Of Hybrid Compounds With Halogenated Amine

Molecular switchable dielectrics,as exciting functional electric materials with the dielectric permittivity undergoing abrupt change between high and low dielectric states at a phase transition temperature,have attracted more and more attention for potential applications in memory devices,data communication,and signal processing.Based on the experiments of dielectric materials,we have designed many interesting compounds,which are combined of 2-chloroethylamine,2-bromoethylamine,2-iodoethylamine,3-chlorpropanamine,3-bromopropanamine and ligands of metal salts,inorganic acids,crown ether,etc.And we try our best to find the phase transition materials.This thesis consists of 11 compounds and their proprieties:Based on 2-bromoethylamine,2-iodoethylamine and metal salts,we have designed compounds?BrC₂H₄NH₃?₃CdBr₅?1?,?NH₃C₂H₄I?₂ PbI₄?2?;based on2-chloroethylamine and metal salts,we succeed to turn the phase transition point from one point to another point through assembling the anions,we obtained compound[NH₂?CH₂?₂Cl]₂[CdCl₃Br]?3?,compound[NH₂?CH₂?₂Cl]₂[CdCl₄]?4?and compound[NH₂?CH₂?₂Cl]₂[CdBr₄]?5?;basedon2-chloroethylamine,3-chlorpropanamine,3-bromopropanamine and inorganic acids,crown ether,we obtained compound NH₃C₃H₆Cl BF₄ C₁₀H₂₀O₅?6?,compound NH₃C₃H₆Br ClO₄C₁₀H₂₀O₅?7?,compound NH₃C₃H₆Cl ClO₅ C₁₀H₂₀O₅?8?,compound NH₃C₂H₄Cl ClO₄C₈H₁₆O₄?9?;based on 3-bromopropanamine and inorganic acids,we obtained NH₃C₃H₆Br ClO₄?10?,?NH₃C₃H₆Br?₂ PF₆?11?.Then we measured the the dielectric properties,differential scanning calorimetry analysis,infrared?IR?,crystal structures,powder X-ray diffraction?PXRD?and infrared?IR?of those compounds.We found phase transition materials through the noticeable dielectric anomaly.Compounds 1,3,4,5 found significant dielectric abnormalities,then further confirmed the temperature of the phase transition by DSC.Through the contrast of crystal structure at high and low temperature,the microcosmic reason of the crystal phase change is obtained.The experimental results show that the phase transition temperature of the compound is mainly due to the order and disorder transformation of amine cations and the change of hydrogen bonds and the change of anion skeletons.