Novel A-?-D-?-A Dye Sensitizers And N/o Fluorine Boron Complex:Synthesis And Optical Performance

Dye sensitizer and fluorine boron complex are the hot research in recent years,hundreds of novel dye molecules are designed and synthesized and proved to have great application prospects in the field of Dye Sensitized Solar Cells?DSSCs?,Fluorescent Switches,Ion Detection and so on.The research topics of the dissertation are synthesis and optical performance of novel A-?-D-?-A dye sensitizers and N/O fluorine boron complex.Two series of sensitizers were designed and synthesized with cyanoacetic acid as the electron acceptor,fluorenone,fluorene or 9,9-dimethyl fluorene as the electron donors,benzene,furan or thiophene as?-bridge respectively.All structures were characterized by ¹HNMR and HRMS and the process and mechanism of key reaction were studied.The spectral properties,electrochemical properties and photoelectric performance were measured.Theoretical calculation was carried out to investigate the structure-property relationship.Two series of N/O fluorine boron complexs based on N-methyl formate substituted phenylhydrazone and salicylaldehyde schiff base structure were designed and synthesized according to the structural characteristics of N/O fluorine boron complexs.All structures were characterized by ¹HNMR and HRMS.Solvent effect,ion selective effect and aggregation-induced emission enhancement effect of N/O fluorine boron compelx and its precursor were tested.Single crystal structure and theoretical calculation based on DFT of some structures were carried out to investigate the structure-property relationship.A series of novel A-?-D-?-A dye sensitizers LV01-LV03 were designed and synthesized with cyanoacetic acid as the electron acceptor,fluorenone as the electron donors,benzene,furan or thiophene as?-bridge respectively.3,6-dibromo-9-fluorenone was coupled successively with 5-formylfuran-2-ylboronic acid,5-formylthiophen-2-ylboronic acid and 4-formyl phenyl boronic acid to obtain dialdehyde compounds respectively.Finally,the dialdehyde reacted with cyanoacetic acid by knoevenagel condensation to get dye sensitizers LV01-LV03.The spectral properties,electrochemical properties,and photoelectric performance were measured.the process and mechanism of suzuki coupling reaction were studied.The results show that photoelectric conversion efficiency of three sensitizers was poor,the reason of that may be the small overlap between HOMO and LUMO.LV01 bearing furan bridge exhibited a higher photoelectric conversion efficiency of 0.98%?Jsc=2.38mA/cm²,Voc=0.55 V,ff=0.75?.A series of novel A-?-D-?-A dye sensitizers LV04-LV06 were designed and synthesized with cyanoacetic acid as the electron acceptor,fluorene as the electron donors,benzene,furan or thiophene as?-bridge respectively.Compared to sensitizer based on fluorenone donor,this series had higher photoelectric conversion efficiency because of good overlap between HOMO and LUMO.LV06 bearing thiophene?-bridge exhibited a higher photoelectric conversion efficiency of 2.35%?Jsc=5.63mA/cm²,Voc=0.60 V,ff=0.70?.Dye sensitizers LV07-LV09 based on 9,9-dimethyl fluoene donor were designed and synthesized to study the effect with properties of A-?-D-?-A sensitizer by the change of donor.The overlap between HOMO and LUMO of this series was better compared with fluorenone and fluorene series.Dye sensitizers bearing dimethyl-fluorene donor showed larger open circuit voltage due to steric effect.LV08bearing furan bridge exhibited a higher photoelectric conversion efficiency of 1.96%?Jsc=3.93 mA/cm²,Voc=0.65 V,ff=0.77?.Dimethyl carbonate reacted with hydrazine hydrate to obtain N-methyl formate hydrazine?IV-1?.Four N-methyl formate substituted phenylhydrazone?IV-2?were obtained by condensation with aromatic aldehydes?ketones?and N-methyl formate hydrazine.Finally,Boron complexation between N-methyl formate substituted phenylhydrazone and BF₃.Et₂O gave the target?IV-3a?.All structures were characterized by ¹HNMR and HRMS.Solvent effect of N/O fluorine boron compelx and its precursor showed that the emission wavelength of IV-2a and IV-2b containing two hydroxyl groups was red shifted 22 nm than that of IV-2c containing one methoxy.The effect of metal ions on the fluorescence properties of IV-2b showed that its fluorescence was greatly enhanced in Ni²⁺and Mg²⁺.In Fe³⁺,the fluorescence of IV-2b was almost completely quenched,indicating that IV-2b may be a fluorescent indicator highly selective for iron ion.Two BF₂ complexes based on schiff base were synthesized by condensation of p-phenylenediamine with salicylaldehyde derivatives,followed by complexation with BF₃·OEt.The fluorescence properties of BF₂ complexes and its precursor were investigated in different organic solvents,With the increase of the electron donating ability,the precursor was obviously red shifted.The structure and packing method of molecule had great influence on the fluorescence properties of solid and the high level V-2c and its precursor V-1c exhibited low fluorescent intensity in the solid state.precursor V-1b exhibited low fluorescent intensity in solution but a high fluorescent intensity as aggregates and in their solid state due to the interesting aggregation-induced emission enhancement characteristics?AIEE?.Meanwhile,the precursor V-1c was proved to be a fluorescent indicator highly selective for copper,the adding 1 equivalent of Cu²⁺could make the fluorescence of V-1c quenched completely.Interference of other metal on detection of Cu²⁺was small.Precursor V-1c exhibited the potential applications as fluorescent probes for copper.