Excited State Adjustable Isoquinoline Sulfonamide Functional Molecules And Unusual Properties

The photoelectric properties of organic functional molecules are hot research topics in the fields of organic electronics,optics,energy storage,and the environment.Controlling the excited state of organic molecules is one of the important means to realize the physical properties of materials.Understanding the nature of electronic excited states is a challenging task,and for many applications in chemistry,molecular physics,molecular biology,and materials science,this task becomes increasingly important.Organic molecules can be excited to a metastable state under external stimulation,forming a unique excited state electronic structure.Generally speaking,the regulation of the excited state of the molecule is aimed at the excited state of electrons,charges,configuration and energy release channels.By controlling the excited state of the molecule,the luminescence behavior of the molecule can be changed,such as thermally excited delayed fluorescence and double-wave emission.Therefore,the control of the excited state at the molecular level is of reference value for the design and synthesis of ideal photoelectric performance materials.In this paper,a class of isoquinoline sulfonamide small molecule compounds were synthesized.Experiments combined with theory,studied the different electron donating ability and steric hindrance of excited substituents on molecular electron charge distribution and its configuration.The specific research contents are as follows:(1)The 3-position chemically modified(diethylamino,diphenylamino,and carbazolyl)phenyl isoquinoline sulfonamides were constructed by using bromobenzene substituted with different functional groups at the para position as raw materials,through two-step Sonogashira coupling reaction and one-step condensation reaction Isoquinoline sulfonamide derivatives(PITA-DEA,PITA-DPA and PITA-Cz),and by means of nuclear magnetic,mass spectrometry and single crystal diffraction analysis we confirmed the molecular structure and configuration characteristics.(2)The difference between the structure of the electron donor and the electron-donating ability in the system has been studied,resulting in the distortion between the isoquinoline and the 3-position phenyl group at the same time as the para-toluenesulfonyl group.The reversal of the two changes the configuration of the excited molecules and the redistribution of the electron cloud,thus exhibited a uniqueluminescence behavior.Among them,the compounds PITA-DEA and PITA-DPA exhibited dual-wave emission properties,and the compound PITA-Cz maintained single-wave emission.At the same time,we studied the configuration and energy of the excited state of the molecule by tuning the spatial confinement of environment and solvent polarity.The emission of the compound in the thin film state was tested,and all three showed single wavelength emission.It was confirmed that the dual-wave emission behavior was indeed derived from the transition of the excited state configuration.The way of controlling the excited state will be of reference value for designing and synthesizing molecules with unique photoelectric properties.(3)Based on the unique and adjustable dual-wave emission properties exhibited by the compound,the ratio of orange and blue emission can be adjusted by changing the external environment of the molecule to achieve organic single molecule white light.There will be potential applications in the field of organic white light materials.