Synthesis And Dielectric And Luminescence Properties Of Hybrid Compounds Based On Morpholine And Cyclohexylamine Derivatives

With the rapid development of the information age,a single responsive material can no longer meet the market’s application requirements for device miniaturization and wide applicability,and the development of materials with multiple responsive properties has gradually become the choice for future development.The phase transition process of dielectric crystals is often accompanied by changes in physical properties such as thermal properties and dielectric properties near the phase transition point when the structural transition occurs.Therefore,phase transition can be used as the basis for finding multiple response materials.Organic-inorganic hybrid phase transition materials have good structural tunability and overcome the disadvantages of low flexibility and high cost of traditional inorganic materials,which are considered to be ideal materials for designing multifunctional responsive materials.However,how to obtain stable multi-response materials by ingenious molecular design methods is still a major challenge due to the complex relationship between structure and properties.The study found that the cyclic organic amine molecules rotate under the stimulation of temperature and other conditions to induce phase transition,and such organic amine molecules can be designed by simple organic synthesis.Therefore,we used cyclic organic amines as the main body and carried out precise molecular modification on them to construct a series of organic-inorganic hybrid materials,and systematically analyzed their physical properties.This thesis mainly discusses the following two parts:The first part is mainly based on morpholine-based molecular modification and assembly of four zero-dimensional hybrid compounds,which are（Cl-MM）₂Mn Br₄（compound 1）、（Br-MM）₂Mn Br₄（compound 2）、（F-EM）₂Mn Br₄（compound 3）and[（N-EM）（18-crown-6）]（Cl O₄）（compound 4）.The second part is mainly composed of cyclohexylamine derivatives as organic cations,combined with metal halides,which are（N-CM）₂Mn Br₄（compound 5）、（Cl-CM）₂Mn Br₄（compound 6）、（Cl-CM）₂Cd Br₄（compound 7）and（Cl-CM）₂Zn Br₄（compound 8）.The eight compounds mentioned above were tested and analyzed by means of single-crystal X-ray diffraction,DSC,dielectric measurement,photoluminescence spectroscopy,etc.The results show that compounds 1-3 all exhibit switchable dielectric phase transition behaviors in their tested temperature ranges.Among them,compound 1 has dual dielectric switching properties,while compound 2 is a multi-responsive material with both dielectric switching and NLO switching.These properties are inseparable from the ingenious chemical modification and symmetry adjustment of cations.In addition,compounds 1,2,5,and 6 with manganese bromide as inorganic units all exhibit green emission photoluminescence characteristics,compound 3 exhibits a unique dual-emission photoluminescence characteristic,and compound 4 have photoluminescence behavior of blue light emission.The comparative exploration of these eight compounds reflects the importance of molecular control design for the development of organic-inorganic hybrid materials,and also provides an experimental basis for the optimization of multifunctional material properties based on-target design.