Synthesis And Application Of Organic Boron Compounds

In recent years,the reaction kinetics and thermodynamics of organic compounds related to carbon,nitrogen and oxygen have been deeply studied,but there are many deficiencies in the research of organic boron compounds with the same period.It is found from the periodic table that the period and main group position of boron have certain particularity,which gives it different photophysical properties in materials.Organic boron compounds are used in organic synthesis as Lewis acid.At the same time,organic boron compounds can also be used as a new synthesis method of reagents and catalysts.The synthetic organic boron compounds can be mainly divided into organic boric acid,organic borane,tetra coordinated organic boron compounds,organic borates and organic borates.In recent years,various methods of catalysis and conversion of organic boron compounds have been published.For example:research on new activation methods for small organic molecules and chemical bonds,creating molecules with special optical properties by utilizing the coordination of empty orbitals to boron atoms,and constructing π-conjugated organic B-N heterocycles to improve the stability of molecules.In addition,the typical reactivity of organoboron compounds is mainly the kinetic direction between neutral trivalent compounds and anionic tetravalent compounds,which shows that there is an ionic reaction mechanism in the synthesis and reaction of organoboron compounds,and tetracoordinated organoboron compounds and organoborane have a wide application potential in photocatalysts,fluorescent probes,organic light-emitting diodes and solar cells.Therefore,this thesis will focus on the synthesis of tetra coordinated organic boron compounds and free radical compounds in organoborane,the exploration of photophysical properties and the study of chemical properties.Firstly,through the summary and exploration of the previous work of our laboratory,the tetra coordinated organic boron compounds are synthesized by replacing 8-amidoquinoline with 2-pyridinamide,resulting in the aggregation induced luminescence effect that the previous compounds did not have.After a series of substrate expansion,it was found that all substrates had the optical characteristics.Then,the selected model molecules were subjected to liquid UV absorption,measurements of fluorescence emission quantum yield and fluorescence lifetime for both solid and liquid,further revealing the novelty of the structure.In addition,the generation of this optical property is also analyzed and described in detail from X-ray single crystal diffraction experiment and density functional theory.Secondly,six kinds of dipyrrolylene compounds were synthesized to react with borane respectively,and some raw materials obtained neutral boron radical compounds.Such experimental results were beyond our expectation.Then,the thermal stability of the obtained boron radical molecules was analyzed and the density functional theory was used to explain the reason for the formation of boron radical compounds.Finally,free radical trapping experiments were carried out on the free radical borides obtained in Chapter 2,but many free radical trapping agents failed to capture this kind of free radicals,which shows that this kind of boron free radical compounds have stability under certain conditions.Next,in order to further find a method to improve the stability of this type of boron radical compound,we tried to coordinate the boron atom and convert the boron-hydrogen bond by using different ligands,and at the same time use the four-coordinate boride to break the intramolecular B-F bond.to try to obtain derivatives of such boron radical compounds.In addition,the design and synthesis of large conjugated symmetrical diboride compounds can make up for the shortcomings in this field.