Exploration On Phase Transition Properties Of The Heterocyclic Amines And Diamines-based Compounds

The ability to control and even switch the responses in multiple physical channels like electrical,magnetic,and optical usually provides coupling as magneto-electric,optoelectronic,and magneto-optic,and consequently lead to novel multifunctional properties.Therefore,those materials which integrate various properties into a single phase have attracted much attention for their wide application in founctional devices.Organic-inorganic materials with rich properties and flexible compositions are going to be one kind of multifunctional materials.To obtain novel organic-inorganic components,we use the strategies of adjusting the molar ratio of reactants and substituting for the components of organic or inorganic part.The research content of this thesis is divided into three parts:In the first part,we use pyridine as the organic anion to react with metal halides,crystallizing and forming four compounds:[C₅NH₆][CdCl₃]（1）,[C₅NH₆][Cd₂Cl₅]（2）,C₅NH₆][MnCl₄]（3）and[C₅NH₆][MnBr₄]（4）.According to the systematic measurements,including differential scanning calorimetry measurements,variable-temperature structural analyses,and dielectric measurements reveal that compound 1and 2 undergoes a notable dielectric anomaly,respectively.In the second part,we obtain four organic-inorganic phase transiton compounds:[CH₃-NC₄H₉][CdBr₃]（5）,[CH₃-NC₄H₉][CdBr₄]（6）,[CH₃-NC₄H₉]₃[Cd₂Br₇]（7）and[CH₃-NC₄H₉][MnCl₃]（8）by the reactions of N-Methylpyrrolidinium and metal halides.Systematic measurements have been performed to investigate the luminescence,phase transition,and prominently dielectric property.The results demonstrate that the four compounds all have dielectric anomaly,among them compound 8 also has optical properties.In the third part,we synthesized three organic-inorganic compounds:[C₅N₂H₁₄][Mn₂Cl₆·4H₂O]（9）,[C₅N₂H₁₄][Cd₂Cl₆]（10）and[C₆N₂H₁₆][Cd₂Cl₆]（11）by the reactions of diamine molecules and metal halides.Systematic measurements were performed to reveal there are not phase transitions and dielectric anomaly.