| Recent years,phase-transitions materials have attracted more and more attention due to their remarkable application in data communication,infrared detection,optical sensing and switchable dielectric devices.And the organic-inorganic hybrids with excellent organic and inorganic properties have rich structure and physical properties and are excellent materials for the synthesis of phase-transition materials.In this study,we designed two different kinds of organic-inorganic hybrid crystals according to halogenated amine and non-halogenated amine,and synthesized a series of novel Mn/Cd-based organic-inorganic hybrid crystals which belong to the above system by the reaction of halogenated and non-halogenated amine with Mn and Cd metal halide.Moreover,we analyzed their possibilities of becoming phase-transition materials from the aspects of single crystal structure,dielectric and phase transition properties etc.The main content of the thesis includes two parts:The first part reported five compounds,[C3H9Cl2NO]2[CdCl4]?1?,[C3H9Cl2NO]2[MnCl4]?2?,[C5H13NBr][Cd3Br7]?3?,[C10H14FN2][CdCl3]?4?and[?C6H6Cl2N?2][CdCl4]?5?.Among them,1 and 2 showed obvious dielectric anomalies at both high and low temperatures,and 3 occurred obvious dielectric anomalies at around 414 K.Moreover,during the DSC measurements,they both showed significant and reversible exothermic-endothermic peaks at the phase transition point.Combined with the difference of their structure before and after the phase transition,we could determine the occurrence of structural phase transition of compound 1-3.However,compounds 4 and 5 showed no dielectric anomaly.The second part reported four compounds,[(C7H10N)2][MnCl4]?6?,[(C4H12N)2][Cd2Cl6]?7?,[(C5H16N2)2][Cd3Cl10]?8?and[(C5H16N2][CdBr4]?9?.Unfortunately,the results of dielectric characterization showed that compounds 6-9 did not exhibit dielectric anomaly during the measurable temperature range.It is initially assumed that they are not the phase-transitions materials that we needed. |
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