Highly efficient persistent organic room temperature phosphorescence(RTP) has attracted increasing attention because of promising applications in fields of chemical sensors, optoelectronic devices, information securit...Highly efficient persistent organic room temperature phosphorescence(RTP) has attracted increasing attention because of promising applications in fields of chemical sensors, optoelectronic devices, information security, and bioimaging, etc. Wherein,the crystal engineering of H-aggregation offers stabilization for long-lived triplet exciton for RTP, but the related research is rare because of the scarcity of ideal phosphorescent H-aggregate. Herein, we designed planar tricoordinate organoboron derivatives with molecular arrangement in ideal H-aggregation. The integration of Br atom can largely enhance RTP efficiency through increasing SOC effect, while the antiparallel molecular arrangement causes annihilation of triplet exciton. Thanks to good selfassembly property, their RTP can even be observed in PMMA matrix with doping ratio of merely 1 wt%. We further found that the cryogenic temperature contributes to stabilizing triplet exciton in H-aggregation, leading to red-shifted phosphorescence. By applying high hydrostatic pressure, the phosphorescence was largely enhanced and redshifted, demonstrating the crucial role of H-aggregation on RTP property. In phosphorescent tissue imaging of live mouse, nanoparticles of BrBA exhibited high contrast image via eliminating the interference of autofluorescence.展开更多
The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the trico...The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the tricoordinate B center makes it exhibit several electronic and steric features,such as electron-accepting ability through p-π~＊ conjugation,the high Lewis acidity to coordinate with Lewis bases,as well as the steric bulk arising from the aryl substituent on the B center to get enough kinetic stability.As a result,the boryl group is a very unique electron acceptor.When an electron-donating amino group is present,the triarylboranes would display intense intramolecular charge transfer transitions,which lead to interesting optoelectronic properties and great utilities.This short review summarizes the recent progress in π-electron systems,which contain both B and N elements and thus display intramolecular charge-transfer transitions.The triarylboranes are introduced based on their structural features,including the linear π-system with boryl and amino groups at the terminal positions,the lateral borylsubstituted π-system with amino groups at the terminal positions,the biphenyl π-system with an amino and a boryl groups at o,o＇-positions,nonconjugated U- and V-shaped π-system,macrocylcic π-system with B and N embedded in the ring,B,N-bridged ladder-type π-system,as well as the polycyclicπ-system with B embedded in the center.展开更多
Structurally-modified acenes with a linear fusion ofπ-extended systems have shown highly attractive properties and promising applications in semiconductor materials,optoelectronic materials and others due to their un...Structurally-modified acenes with a linear fusion ofπ-extended systems have shown highly attractive properties and promising applications in semiconductor materials,optoelectronic materials and others due to their unique electronic structures.We have accessed a series of anthra/tetra/pentaquinodimethane-supported organoboranes,Mes^(*)B-A,Mes^(*)B-T and Mes^(*)B-P,with highly tunable emissions from blue to red(~680 nm)by controlling the number of fused benzene rings of the[n]acene core(n=3-5).Interestingly,these redox-switchable quinoid systems have chemically and electrochemically enabled two-electron oxidations,leading to dicationic anthracene,tetracene and pentacene segments(Mes^(*)B-A^(2+),Mes^(*)B-T^(2+)and Mes^(*)B-P^(2+))as evidenced by new absorption bands in the UV−vis−NIR spectra and spectroelectrochemical studies.Meanwhile,all the molecules feature aπ-conjugated,overcrowded ethylene structure that allows for a spin-state transition from closed-shell to the open-shell diradicals(Mes^(*)B-A^(2+),Mes^(*)B-T^(2+)and Mes^(*)B-P^(2+))under thermal conditions.This can further be confirmed by the variable-temperature(VT)^(1)H NMR and electron spin resonance(ESR)spectroscopy.These organoboranes also experienced an emission change in response to fluoride binding with electron-deficient boron centers.Our current work demonstrates not only the synthetic contribution to[n]acene-based luminescent materials,but also showcases multistate transformations for potential applications depending on well-tuned electronic,magnetic,electron transfer and charge transport mechanisms.展开更多
基金supported by the National Natural Science Foundation of China(21905198)the Starting Grants of Tianjin University,Tianjin Government.
文摘Highly efficient persistent organic room temperature phosphorescence(RTP) has attracted increasing attention because of promising applications in fields of chemical sensors, optoelectronic devices, information security, and bioimaging, etc. Wherein,the crystal engineering of H-aggregation offers stabilization for long-lived triplet exciton for RTP, but the related research is rare because of the scarcity of ideal phosphorescent H-aggregate. Herein, we designed planar tricoordinate organoboron derivatives with molecular arrangement in ideal H-aggregation. The integration of Br atom can largely enhance RTP efficiency through increasing SOC effect, while the antiparallel molecular arrangement causes annihilation of triplet exciton. Thanks to good selfassembly property, their RTP can even be observed in PMMA matrix with doping ratio of merely 1 wt%. We further found that the cryogenic temperature contributes to stabilizing triplet exciton in H-aggregation, leading to red-shifted phosphorescence. By applying high hydrostatic pressure, the phosphorescence was largely enhanced and redshifted, demonstrating the crucial role of H-aggregation on RTP property. In phosphorescent tissue imaging of live mouse, nanoparticles of BrBA exhibited high contrast image via eliminating the interference of autofluorescence.
基金the National Natural Science Foundation of China(Nos.21072117,21272141,21572120)for financial support
文摘The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the tricoordinate B center makes it exhibit several electronic and steric features,such as electron-accepting ability through p-π~＊ conjugation,the high Lewis acidity to coordinate with Lewis bases,as well as the steric bulk arising from the aryl substituent on the B center to get enough kinetic stability.As a result,the boryl group is a very unique electron acceptor.When an electron-donating amino group is present,the triarylboranes would display intense intramolecular charge transfer transitions,which lead to interesting optoelectronic properties and great utilities.This short review summarizes the recent progress in π-electron systems,which contain both B and N elements and thus display intramolecular charge-transfer transitions.The triarylboranes are introduced based on their structural features,including the linear π-system with boryl and amino groups at the terminal positions,the lateral borylsubstituted π-system with amino groups at the terminal positions,the biphenyl π-system with an amino and a boryl groups at o,o＇-positions,nonconjugated U- and V-shaped π-system,macrocylcic π-system with B and N embedded in the ring,B,N-bridged ladder-type π-system,as well as the polycyclicπ-system with B embedded in the center.
基金supported by the Beijing Natural Science Foundation(No.2232024).
文摘Structurally-modified acenes with a linear fusion ofπ-extended systems have shown highly attractive properties and promising applications in semiconductor materials,optoelectronic materials and others due to their unique electronic structures.We have accessed a series of anthra/tetra/pentaquinodimethane-supported organoboranes,Mes^(*)B-A,Mes^(*)B-T and Mes^(*)B-P,with highly tunable emissions from blue to red(~680 nm)by controlling the number of fused benzene rings of the[n]acene core(n=3-5).Interestingly,these redox-switchable quinoid systems have chemically and electrochemically enabled two-electron oxidations,leading to dicationic anthracene,tetracene and pentacene segments(Mes^(*)B-A^(2+),Mes^(*)B-T^(2+)and Mes^(*)B-P^(2+))as evidenced by new absorption bands in the UV−vis−NIR spectra and spectroelectrochemical studies.Meanwhile,all the molecules feature aπ-conjugated,overcrowded ethylene structure that allows for a spin-state transition from closed-shell to the open-shell diradicals(Mes^(*)B-A^(2+),Mes^(*)B-T^(2+)and Mes^(*)B-P^(2+))under thermal conditions.This can further be confirmed by the variable-temperature(VT)^(1)H NMR and electron spin resonance(ESR)spectroscopy.These organoboranes also experienced an emission change in response to fluoride binding with electron-deficient boron centers.Our current work demonstrates not only the synthetic contribution to[n]acene-based luminescent materials,but also showcases multistate transformations for potential applications depending on well-tuned electronic,magnetic,electron transfer and charge transport mechanisms.
