Design,Sythesis And Structure-activity Relationships Of Novel Topological Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons（PAHs）have broad application prospects in the field of organic optoelectronics,bio-optoelectronics due to their unique conjugated structures.Although there are thousands of fused ring molecules have been synthesized,the strong intermolecular interactions of fused aromatic hydrocarbons lead to poor solubility,severely limiting the applications of such materials.Therefore,it is very important to design and synthesize new fused ring aromatic hydrocarbon molecules with good solubility and novel topology characteristics.The main work of this thesis is to design and synthesize novel topological polycyclic aromatic hydrocarbon molecules,improve the solubility of materials through the distortion of conjugated structure and the introduction of alkyl side chains,and the molecules are applied to preparation of organic field-effect transistors and organic solar cell devices according to the structural characteristics of materials.For the first time,nanoparticles with highly twisted fused ring molecules are prepared by co-precipitation method for bioimaging and photodynamic therapy.The details are as follows:1.A novel tandem reaction synthesis route involving no transition metals is attempted.Preliminary investigations on the preparation of three pyrrole-containing heteroacenes,dithienobenzo-carbazoles（DTBCz compounds of DTB[23]Cz,DTB[32]Cz and DTB[32,34]Cz）,by using carbazole as the starting material.We compare their photophysical,HOMO/LUMO levels and phase transitions to afford a fundamental understanding of the position isomerism on DTBCz backbones.These DTBCz isomers have suitable HOMO energy levels and solubility as p-channel organic semiconductors for solution-processed OFET application.The most angular shaped DTB[32,34]Cz exhibits an interesting OFET behavior with weak response to the thickness of the active layer.Moreover,we convey the idea that this synthetic methodology could be extended to prepare higher order acenes with carbazole or other commercially available building blocks.2.A universal synthetic method to synthesize a fused aromatic hydrocarbon with both triphenylene-cored trimeric fluorene/trimeric carbazole are designed.First,the carbazole derivatives are selected as the raw material through the stepwise cross-coupling reaction and the final Scholl reaction to prepare the target molecule.Due to the region selection effect of the carbazole ring-fused reaction,the completely central symmetric fused aromatic hydrocarbon molecule has not obtained.After optimization of design ideas,trimethyltriphenylene is selected as raw material to prepare highly central symmetric TP series fused ring molecules by cross-coupling and Pd-catalyzed benzyl and halogen coupling reaction.Due to the highly central symmetry of the TP series of molecules and the extended conjugated structure,the self-assembly characteristics of the typical molecular TP-A in solution and solid state are carefully studied,and the material with higher single carrier current is measured by the space-limited current method(0.41 cm² V^-1 S^-1).This work provides a reference for the development and design of novel C₃ symmetric fused ring molecules and their applications.3.Herein,newly synthesized fused dimeric PDI electron acceptors with the central pyrene rigidly fused at its non-K-region and K-region are demonstrated.The more contorted 49-Py-PDI exhibits higher photoluminescence efficiency both in solution and film states,less molecular interaction in thick concentrated solutions and in solid films.Moreover,49-Py-PDI shows efficient charge separation by the PL quenching experiments,achieved the highest power conversion efficiency（PCE）of 4.53%with a high V_OC values（～1.0 V）.Which shows that the design strategy by introducing rigid and steric hindrance to increase intermolecular strain to construct fully ring fused contorted acceptors is an effective approach for the development of novel non-fullerene acceptors.4.A series of PDI-based fused ring-derived molecules（27-Py-PDI,49-Py-PDI and 49-Na-PDI）are designed and synthesized,the 49-Py-PDI shows highly contorted structure which is caused by conjugated crowding.On the one hand,the distorted molecule exhibits strong fluorescence（Φ=0.9）.On the other hand,the contorted structure enhances the intramolecularly spin-orbit coupling the probability of inter-system crossing.The singlet state test shows that the contorted molecule49-Py-PDI own highly singlet oxygen yield（η=0.59）.Photodynamic therapy experiments show that the 49-Py-PDI can produces singlet oxygen under light conditions.This work shows that the design of a contorted structure can improve the singlet oxygen yield of the material while maintaining the strong fluorescence of the conjugated molecule,which has important guiding significance for designing and synthesizing of novel photosensitizers.