Study On The Synthesis And Property Of Optoelectronic Materials Based On The BF₃ ·Et₂O Catalysed Friedel-Crafts Reaction

The BF₃·Et₂O-mediated Friedel-Crafts reaction possesses the advantages of mild conditions, convenient process, innocuity and environment friendly, and so on. Based on it, organic semiconducting materials with the H-shaped, spindle-shaped and dendritic topological structures present unique attraction in the organic light-emitting field, e.g., Organic Solar Cell (OSC), Organic Light-Emitting Diode (OLED), Organic Field-Effect Transistors (OFET), organic electrical memory and sensor etc.First, a series of linear, dumbbell-shaped and dendritic 9,9-diarylfluorenes has been prepared by the BF₃·Et₂O-mediated tertiary-alcohol Friedel-Crafts reaction, in which stereo-hindered groups such as phenylfluorenes and xanthene were efficiently introduced into the electron-rich aromatic groups, e.g., thiophene, bithiophene and carbazole etc. Spectroscopy of T1 series shows it is efficient for regulation by oxidation with the spectral red shift about 129 nm after thiophene oxidation while stereo-hindered group, phenylfluorenes, results in spectral blue shift about 70 nm in the spectrum of T2 and T3 series from which we conclude that molecular interchain interaction has been contrlled, molecular conformation ofπstacking changed and energy band regulated by the introduction of phenylfluorenes. Based on it, optimizing organic semiconducting performances can be designed.Simultaneously, BF₃·Et₂O-mediated Friedel-Crafts reaction has been in-depth learned with the research of the influences of various factors (e.g., feeding ratio, feeding order, reaction temperature, reaction time and reaction substrates etc.) on reaction product and yield, which offers reference basis for optimum design and reaction conditions. In the experiment, substitution number of PFMs has been controlled by feeding ratio with the further influence upon light-emitting property and thermostability. Differential scanning calorimetry (DSC) shows the glass temperature of maternal hole-transporting materials has been enhanced by end-capped PFMs, presenting the diversity of molecular conformation and stronger steric hinderance effect. Moreover, reactive activity and spectroscopic properties has been influenced by introducing the atoms of polycyclic heterocycles which decreases Friedel-Crafts reactive activity to a large extent and induces spectral red shift.The influence of steric hinderance and substitutional group on energy band and intramolecular or intermolecularπstacking of materials has been researched by the introduction of phenylfluorenes into the C3 and C6 position of carbazole and then substitutional group, e.g., pyrene, biphenyl, fluorenone and alkyl carbazole etc. into C1 position, and which offers reference basis for controllable design and optimum energy levels of light-emitting materials by means of the interactive combination of theoretical simulation calculation and experiment. The peak shape and value have barely been influenced by the introduction of steric-hinder groups into the C3 and C6 position from spectroscopy of dilute solution which shows HOMO and LUMO energy levels concentrate on carbazole group.Dendrimers are the third light-emitting materials besides organic small moleculars and polymers, which possess both advantages of the former definite structure and the latter strong stability and consequently have broad application prospect, whereas limitation lies in its complicated synthesis and low yield. Dendrimers with high yield and environment friendly have been successfully obtained based on the BF₃·Et₂O-mediated Friedel-Crafts reaction,where green emission of fluorenone can be efficiently depressed by branched structure of G5 dendrimer which are aimed at the field of OPV and OLED. It can provide useful and new synthesis methods as well.In summary, a series of complicated diarylfluorenes has been prepared by the BF₃·Et₂O-mediated Friedel-Crafts reaction. The influence of stereoscopic effect on energy band and intramolecular or intermolecularπstacking has been researched by the introduction of steric-hinderance group into molecular, with the further exploration of the relationship of molecular structure and property of materials. At the same time, a series of dendrimers with high yield has been successfully obtained by the BF₃·Et₂O-mediated Friedel-Crafts reaction, which is aimed at the research in the field of organic semiconducting devices by photochemical and electrochemical characterization.