Synthesis And Photoelectric Properties Of Diamond Type Gridarene Based On “A2+B2” Mode

Axial chiral spiro compound is a special case of axial chiral molecule.This kind of molecule not only contains the characteristics of axial chiral molecule,but also own distinctive characteristics of spirane structure.Axial chiral spiro compounds have been widely used in photoelectric field,molecular electronic devices,semiconductor light emitting devices,solar cells and the control of conjugation length.Based on these advantages,they were introduced into the structure of nanogridarenes to obtain novel structures and properties and make contributions to the research and development of nanogridarenes.The work of this paper mainly include the following three aspects:1.Using 9-(4-octyloxy)phenyl-9-hydroxy-fluorenyl-2-boronic acid pinacol ester and 2,2'-dibromo-9,9-spirobifluorene as raw materials,L-shaped molecule containing spirobifluorene were synthesized by Suzuki coupling reaction.This A2 type synthon di-tertiary alcohol substituted spirobifluorene composed of one spirobifluorene unit and two 9-octoxyphenyl tertiary alcohol units.The yield is 84%.There are six isomers of spirobifluorene di-tertiary alcohol in theory,but in the reaction,through the TLC of di-tertiary alcohol substituted spirobifluorene,only three isomers are observed.The three structures were separated by column chromatography,and the possible corresponding structures of each isomer were analyzed.The three isomers DOHSBF-isomer 1?DOHSBF-isomer 2 and DOHSBF-isomer 3 were obtained with yields of 15%,24.5%,and 44.5%,respectively.The structures of the three isomers were confirmed by MALDI-TOF,¹H NMR spectrum and ¹³C NMR spectrum.At the same time,the di-tertiary alcohol substituted spirobifluorene and its isomers were characterized by UV-PL spectroscopy.Simultaneous annealing and photooxidation were carried out.The results showed that the di-tertiary alcohol substituted spirobifluorene and its isomers,no matter under 220?annealing conditions,or after 365 nm ultraviolet light photooxidation test,the spectrum did not change significantly,indicating that the di-tertiary alcohol substituted spirobifluorene has good light and thermal stability.The unseparated isomer of di-tertiary alcohol substituted spirobifluorene and the three isomers were characterized by TGA.The characterization results showed that the di-tertiary alcohol substituted spirobifluorene sample without separation of isomers has the highest thermal stability,and the 5%mass loss temperature is 316?,and among the three isomers,DOHSBF-isomer 2 has the worst thermal stability,with a 5%mass loss temperature of 229?,while DOHSBF-isomer 1 and DOHSBF-isomer 3 have similar thermal stability,with 5%mass loss temperatures of 238?and 241?,respectively.2.Using A2 type synthon di-tertiary alcohol substituted spirobifluorene(DOHSBF)and B2 type synthon 2,2'-bis(2-thienyl)-9,9'-spirobifluorene(DTh SBF)as raw materials,boron trifluoride ether as the catalyst,a one-step synthesis of A2+B2 type diamond-type nanogrid(DG)containing two spirobifluorene units,two tertiary alcohol units and two thiophene units,was synthesized with a yield of 64%by Friedel-Crafts reaction.There are eight isomers of DG theoretically.However,only four spots were observed on the TLC plate.Column chromatography was performed to separate three products:DG-isomer 2(15%),DG-isomer 3(5%)and the subsequent isomer mixture DG-isomer 4(44%).The structures of the three products were confirmed by MALDI-TOF,¹H NMR spectrum and¹³C NMR spectrum.To study the lattice effect,we characterized the lattice precursor and DG by UV-PL spectroscopy.It was found that in the solution state,the absorption spectrum of DG was redshifted by 17 nm compared to DTh SBF and a red shift of 1 nm compared to DOHSBF.In the emission spectrum,the maximum emission peak of redshifted DG is 19 nm red-shifted compared to DTh SBF,and 3 nm redshifted compared to DOHSBF.In the film state,in the absorption spectrum,the maximum absorption peak of DG is blue-shifted by 15 nm compared to spirobifluorene dithiophene,and red-shifted by 6 nm compared to DOHSBF.In the emission spectrum,the maximum emission peak of the DG is 4 nm red-shifted relative to DTh SBF,and 6 nm red-shifted compared to DOHSBF.3.Using A4 type synthon tetra-tertiary alcohol substituted spirobifluorene(TOHSBF)containing one spirobifluorene unit and four tertiary alcohol units and B2 type synthon dithiophene substituted spirobifluorene(DTh SBF)as raw materials,using boron trifluoride ether as the catalyst,the spirodigrid(SDG)was synthesized in one step with a yield of 65%by Friedel-Crafts reaction.The SDG structure contains three spirobifluorene units,four tertiary alcohol units,and four thiophene units.There are 68 theoretical isomers of SDG.However,in the reaction,seven points can be observed through the TLC plate.The structure of SDG was confirmed by MALDI-TOF,¹H NMR spectrum and ¹³C NMR spectrum.In order to have a further understanding of gridization effect,we studied the UV-PL spectra of SDG molecules in solution and film state,and found that in the solution condition,compared with TOHSBF,the red shift of the absorption spectrum of SDG is 20 nm and the red shift of the emission spectrum is 5 nm.In the film condition,compared with the synthon,the absorption spectrum of the SDG is blue-shifted by 24 nm,and the emission spectrum is red-shifted by 14 nm.