Study On Solvation And Aggregation Effects Of Sulfur-Containing ?-Conjugated Molecules

Sulfur is one of the elements widely found in nature.In recent years,?-conjugated molecular material systems have become a hot spot in the field of organic synthesis.?-conjugated molecules and derivatives containing sulfur are an important material system.Such materials are mainly a structure in which a double bond and a benzene ring alternate,or a benzene ring in which a sulfur atom is substituted for a site,which is a good?-electron conjugated skeleton.The sulfur atom has a large radius,various chemical bond positions,low bond energy and easy bonding,and it is easy to introduce other specific functional groups to adjust the properties of the compound during synthesis,and its strong electron-withdrawing ability effectively regulates its polarity and luminescence characteristics,which is beneficial to Electron injection,combined with the twisted conjugate unit,can effectively control the conjugate length,which is beneficial to the regulation of the illuminating wavelength,and also has good thermal stability and its shape stability.The absorption and fluorescence of the sulfur-containing?-conjugated molecules synthesized in this paper are in the visible light range,which facilitates the study of solvent and aggregation effects.By studying the absorption spectra of sulfur-containing?-conjugated molecules and the changes of fluorescence spectra under different solvent environments,we can understand the spectral responses in different solvations and aggregates,and understand the sulfur elements in different?conjugated molecular structure play different functions.In this thesis,different organic synthesis methods were used to effectively control the?-conjugated length of sulfur-containing molecules.The absorption spectra of sulfur-containing?-conjugated molecular materials synthesized by the authors under different solvents were measured by absorption spectroscopy and fluorescence spectroscopy.By changing the solvent polarizability,its absorption spectrum is red-shifted,and then its S₁ energy level position,aggregation-induced luminescence and other characteristics are modulated,and the effects of different solvents on absorption spectrum,fluorescence spectrum and aggregation-induced luminescence are observed.The innovations achieved are as follows:1.The absorption and fluorescence spectra of a mixed solution of?-conjugated molecules containing sulfur are different in different polar solvents.Its fluorescence intensity increases as the polarity of the solvent increases.Changes in external environmental conditions,such as temperature and solvent effects, have a regulatory effect on the?-electron delocalization of sulfur-containing,and the delocalized?-electrons have an effect on molecular order.As the polarity of the solvent is changed,the dipole moment of the?-conjugated molecule containing sulfur changes,resulting in the occurrence of electron transfer.2.A solvent which is polar and has a large polarizability,thus producing a high aggregation efficiency.When dissolved in different concentrations of polar solvents,the luminous efficiency also changes correspondingly,which is related to the structural change of the?-conjugated molecule containing sulfur.