"Push-pull"1,8-Naphthalic Anhydride With Linear Triphenylamine Oligomer As Electron Donor

Due to the unique photophysical properties,1.8-naphthalimide compounds have found application in various areas of chemistry. Moreoever, their absorption and emission spectra can be easily tuned through careful structural modification on either the aromatic’naphthalene’moiety itself, or at the nitrogen of the imide site. Consequently, the1,8-naphthalimide compounds has been extensively used as strongly absorbing and colorful dyes, building block for artificial lightharvesting arrays, as well as fluorescence chemical probes, particularly for the sensing of biologically relevant cations and anions.In chapter1, the research of synthesis, properties and applications of naphthalimide derivatives have been reviewed. The relationship between structure and photophysical properties will be the forcuse of our research.In chapter2, we synthesize a series of "Push-Pull"1,8-naphthalic anhydride with linear triphenylamine oligomer as donor, which are named as Compound2, Compound3, Compound4and a reference molecule1. Their molecular structures were fully characterized by1H NMR, Maldi-tof mass as well as elementary analysis.In chapter3, the photophysical properties of these compounds were investigated by the steady state electronic absorption and fluorescecne spectra, electrochemistry, theoretical calculation. The result indicates that with the increase on the number of triphenylamine groups at the "push" end, the absorption maximum red-shift and the energy gap between HOMO and LUMO decrease gradually. The decrease on the HOMO/LUMO energy gap is primarily caused by the increase on the energy level of HOMO. The fluorescence quantum yields of these compounds decrease also along with the increase on the number of triphenylamine groups at the "push" end due to the enhanced electron donating ability. The fluorescence quantum yields of compound3and4are extremely small, which is because the process induced by photo excitation is no more ICT, but electron transfer from triphenylamines to naphthalic anhydride instead. More interestingly, compound3show a very weak emission at560nm after excitation at440nm. This weak emission might be assigned to a special ICT, which involve a high energy transition, such as the transition from HOMO-1to LUMO. The results of this research revealed that for a "push-pull" molecule, strong electron donating ability at the "push" end could change the ICT into electron transfer and lead to a completely fluorescence quenching.In chapter4, we described the synthesis and structural charactrizations of a novel dibenzofuran compound, which is decorated with triphenylamine groups.