Synthesis And Properties Of Intramolecular Charge-transfer Compounds Based On Nitrogen-containing Heterocycles

Intramolecular charge-transfer (ICT) compounds are important functionalphotoelectric materials whose photoelectric properties could be tuned by changing theefficiency of electron transfer. The ICT compounds have been drawn great attentionbecause of their potential applications in many fields, such as chemical sensor, solarcells, nonlinear optical materials. Based on the importance of ICT compounds, thisthesis focuses on design and synthesis of novel ICT compounds, and investigation oftheir self-assemble behaviors and structural, photophysical, electrochemical properties.Futhermore, the third-order nonlinear optical properties of the ICT compounds arealso studied. The main contents are as follows:Chapter One is an introduction about the main methods of synthesis andassembly, properties and applications of ICT compounds in different fields.In Chapter Two, four kinds of ICT compounds that incorporateN,N-dimethylaniline or carbazole as the common electron donor and3-phenyl-5-isoxazolone as the electron acceptor moiety, have been synthesized andtheir structural, photophysical properties were investigated. Their maximumabsorption peaks and fluorescent emission peaks would red shift as the strength of the electron donor increases. Meanwhile, these ICT compounds could be self-assembledinto different well-ordered structures such as ribbon-like architectures, rhombicplate-like architectures, hollow nanospheres and multilayered plates by differentmethods. What’s more, the third-order NLO properties of these compounds in solutionwere investigated through Z-scan technique. They exhibited good third-order NLOabsorption and refraction effects.In Chapter Three, three ICT compounds with better optical properties in whichN,N-dimethylaniline or carbazole worked as the common electron donor and2,1,3-benzothiadiazole acted as the electron acceptor moiety have been synthesized.Their structural, photophysical and electrochemical properties were investigated. TheHOMO, LUMO and band gap levels obtained from electrochemical measurementwere in good agreement with the theoretical calculations from B3LYP/cc-pVDZmethod. At the same time, the third-order NLO absorption and refraction propertieswere measured by Z-scan technique. Because of the stronger electron acceptor, theNLO absorption coefficient and refractive index are much larger than those of thecompounds in Chapter Two. They could be good candidates for NLO materials andwould have potential application in optical devices.In Chapter Four，the main research results of the thesis have been summarized.