Novel Organic Boron Luminescent Materials:Synthesis,Photophysical Properties And Application

In recent years,?-conjugated luminescent materials containing three-coordinated or four-coordinated boron have attracted the research interest of many scholars at home and abroad due to their special photoelectric properties.Its excellent light-emitting properties and charge transport properties make it widely used in the fields of optics and optoelectronics,such as electroluminescence,chemical sensing,photochromism,and biomolecule recognition.In this paper,a series of boron-containing luminescent compounds with new molecular structures are designed and synthesized by introducing electron donors or adjusting the coordination number of boron.The target compounds were characterized and confirmed by ¹H NMR,¹³C NMR and mass spectrometry.Their photophysical properties,thermal stability properties,and electrochemical propertieshe are investigated by using theoretical calculation,ultraviolet-visible absorption spectrum,emission spectrum,differential scanning calorimetry?DSC?,and cyclic voltammetry.The relationship between material structure and performance was discussed,and the applications of these luminescent materials were studied.1. Using phenothiazine as a central group and covalently bonding three-coordinated boron groups around it,two kinds of phenothiazine-tri-coordinated boron luminescent materials B-PTZ and 3B-PTZ with D-A structure were synthesized.The photophysical properties and fluorescence sensing performance were studied by using density functional theory,ultraviolet-visible absorption spectrum and fluorescence emission spectrum.B-PTZ and 3B-PTZ have high fluorescence quantum efficiency,good electrochemical stability and thermal stability.B-PTZ has thermally activated delayed fluorescence properties.B-PTZ and 3B-PTZ are expected to be excellent electroluminescent materials through reasonable device structure design.At the same time,both B-PTZ and 3B-PTZ can be used as high-efficiency fluoride ion fluorescence probes to identify fluoride ions.With the addition of fluoride ions,the fluorescence emission of B-PTZ in tetrahydrofuran shows fluorescence quenching,and the fluorescence emission 3B-PTZ in tetrahydrofuran shows red shift and the fluorescence quenching.2. Three-coordinated organic boron groups and N,C-chelated four-coordinated boron groups were introduced into the molecule at the same time,and two new types of organic boron luminescent materials p-2BQ and m-2BQ were synthesized,to study the synergistic effect of these two types of groups and their effects on the properties of luminescent materials.The photophysical properties and fluorescence sensing performance were studied using density functional theory,ultraviolet-visible absorption spectrum and fluorescence emission spectrum.Both p-2BQ and m-2BQ have high fluorescence quantum efficiency,and both can be used as efficient fluoride ion fluorescent probes to identify fluoride ions.With the addition of fluoride ions,the p_?-?conjugate effect of the molecule is broken,and the fluorescence emission of p-2BQ and m-2BQ in tetrahydrofuran show red shifted and fluorescence quenching.3. An electron donor triphenylamine group?TPA?was introduced into the N,C-chelated tetracoordinated boron system through molecular design,and two organic boron luminescent materials p-TABQ and m-TABQ with D-A structure were synthesized and used to study the synergy between these two groups and their effects on the properties of luminescent materials.The compounds p-TABQ and m-TABQ have high fluorescence quantum efficiency,good electrochemical stability and thermal stability,and have application potential in the field of organic electroluminescent devices.Because the molecules contain B-N coordination bonds,and without the triarlboron unit,P-TABQ and m-TABQ have more stable molecular structures and do not show responsiveness to fluoride ions.