Developing efficient and long wavelength sensitive unimolecular photoinitiators(PIs)is still facing a great challenge.In this work,a series of thioxanthone-based N-hydroxyphthalimide esters(TX-NHPIEs)were synthesized ...Developing efficient and long wavelength sensitive unimolecular photoinitiators(PIs)is still facing a great challenge.In this work,a series of thioxanthone-based N-hydroxyphthalimide esters(TX-NHPIEs)were synthesized by installing NHPIEs along the TX backbone and characterized.The investigated TX-NHPIEs have a 60 nm redshift and demonstrate sterling initiating efficiency for free radical photopolymerization(FRP)under LED@450 nm light irradiation compared with the commercialized isopropylthioxanthone(ITX).Real-time1Hnuclear magnetic resonance(1H NMR),electron spin resonance(ESR),decarboxylation and gas chromatograph-mass spectrometer(GC–MS)experiments and density functional theory(DFT)reveal that TX-NHPIEs can generate one alkyl radical and one N-centered iminyl radical,which can initiate FRP directly and indirectly,respectively.In other words,TX-NHPIEs absorb one photon and can generate two active radicals,which break through the limitations of common PIs.TX-NHPIE-Cpe demonstrates the highest initiating efficiency,and its application in coatings and 3D printing was also studied,indicating TX-NHPIEs have broad potential applications in photopolymerization processes.展开更多
The currently reported axial chiral molecules based on the 3,3'-substitution of the binaphthyl skeleton are limited by intrinsic fluorescence properties,resulting in generally low device efficiencies(EQE<5%)of ...The currently reported axial chiral molecules based on the 3,3'-substitution of the binaphthyl skeleton are limited by intrinsic fluorescence properties,resulting in generally low device efficiencies(EQE<5%)of related organic light emitting diodes(OLEDs).Herein,we designed and synthesized four pair of chiral binaphthyl enantiomers(R/S-1-R/S-4)adopting acceptor-donor-donor-acceptor(ADDA)structure by introducing different thioxanthone modification groups on the 3,3'-position of 2,2'-dimethoxy-1,1'-binaphthalene.Among them,emitter R/S-2 and R/S-4 obtained by enhancing intramolecular charge transfer exhibited TADF characteristics due to relatively small Est of 0.12eV and 0.17eV,and relatively moderate SOC matrix elements of 0.28 cm^(-1)and 0.10 cm^(-1)between the 1CT and 3LE states.The CD spectra of these enantiomers in diluted solutions showed perfect mirror images and reasonable gabs for small organic molecules(10^(-4)-10^(-3)).And the external quantum eficiencies(EQE)of 10.9%and 8.32%for device A and B based on emitter S-2 and S-4 were highest compared with currently reported axial chiral molecules based on the 3,3'-position substitution of binaphthyl skeleton,providing simple molecular design strategies to construct efficient CP-OLED device.展开更多
基金the financial support by the National Natural Science Foundation of China(Nos.22301107,52373057)the Nature Science Foundation of Jiangsu Province(No.BK20200610)+1 种基金the Fundamental Research Funds for the Central Universities(No.JUSRP122021)Jiangsu Province"Innovation and Entrepreneurship Doctor"Talent Plan(No.JSSCBS20221053)also provided support。
文摘Developing efficient and long wavelength sensitive unimolecular photoinitiators(PIs)is still facing a great challenge.In this work,a series of thioxanthone-based N-hydroxyphthalimide esters(TX-NHPIEs)were synthesized by installing NHPIEs along the TX backbone and characterized.The investigated TX-NHPIEs have a 60 nm redshift and demonstrate sterling initiating efficiency for free radical photopolymerization(FRP)under LED@450 nm light irradiation compared with the commercialized isopropylthioxanthone(ITX).Real-time1Hnuclear magnetic resonance(1H NMR),electron spin resonance(ESR),decarboxylation and gas chromatograph-mass spectrometer(GC–MS)experiments and density functional theory(DFT)reveal that TX-NHPIEs can generate one alkyl radical and one N-centered iminyl radical,which can initiate FRP directly and indirectly,respectively.In other words,TX-NHPIEs absorb one photon and can generate two active radicals,which break through the limitations of common PIs.TX-NHPIE-Cpe demonstrates the highest initiating efficiency,and its application in coatings and 3D printing was also studied,indicating TX-NHPIEs have broad potential applications in photopolymerization processes.
基金funded by National Natural Science Foundation of China(No.21772209)International Partnership Program of Chinese Academy of Sciences(IPP)(No.1A1111KYSB20210028)National Program for Support of Top-notch Young Professionals.
文摘The currently reported axial chiral molecules based on the 3,3'-substitution of the binaphthyl skeleton are limited by intrinsic fluorescence properties,resulting in generally low device efficiencies(EQE<5%)of related organic light emitting diodes(OLEDs).Herein,we designed and synthesized four pair of chiral binaphthyl enantiomers(R/S-1-R/S-4)adopting acceptor-donor-donor-acceptor(ADDA)structure by introducing different thioxanthone modification groups on the 3,3'-position of 2,2'-dimethoxy-1,1'-binaphthalene.Among them,emitter R/S-2 and R/S-4 obtained by enhancing intramolecular charge transfer exhibited TADF characteristics due to relatively small Est of 0.12eV and 0.17eV,and relatively moderate SOC matrix elements of 0.28 cm^(-1)and 0.10 cm^(-1)between the 1CT and 3LE states.The CD spectra of these enantiomers in diluted solutions showed perfect mirror images and reasonable gabs for small organic molecules(10^(-4)-10^(-3)).And the external quantum eficiencies(EQE)of 10.9%and 8.32%for device A and B based on emitter S-2 and S-4 were highest compared with currently reported axial chiral molecules based on the 3,3'-position substitution of binaphthyl skeleton,providing simple molecular design strategies to construct efficient CP-OLED device.
