Fast,precise structure determination of unknown compounds has been the foundation but with a persistent challenge in the field of chemical research.Among various chemical characterization techniques,single-crystal X-r...Fast,precise structure determination of unknown compounds has been the foundation but with a persistent challenge in the field of chemical research.Among various chemical characterization techniques,single-crystal X-ray diffraction(SCXRD)stands out as the most straightforward and accurate method in modern structural chemistry.By precisely determining the three-dimensional arrangement of atoms within a crystal,it provides direct atomic-level evidence for understanding the relationship between material structure and properties[1].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
Open-shell chiral diradicals that feature both the unique chiroptical properties and tunable spin states have kindled numerous interests in organic synthesis and material science.We present a new class of such model s...Open-shell chiral diradicals that feature both the unique chiroptical properties and tunable spin states have kindled numerous interests in organic synthesis and material science.We present a new class of such model systems based on theπ-extended planar chiral pillar[5]arene derivatives P5Flu and P5Cz,where the pillar[5]arene-based chiral scaffolds are coupled with sterically encumbered fluorenyl and carbazolyl moieties as highly luminescent redox-active emitters,respectively.Both molecules in neutral states can readily undergo chemical oxidations leading toπ-conjugated chiral diradicals of the dehydrogenated P5Flu^(2·)and a positively charged dication P5Cz^(2+2)·.Characterization of the resulting Müller’s open-shell species by variable-temperature electron spin resonance(VT-ESR),UV-vis-NIR absorption,VT-NMR and by computational studies revealed a singlet(ΔE_(S-T)=-1.63 kcal mol^(-1))and a nearly degenerate singlet-triplet ground state(ΔE_(S-T)=0.05 kcal mol^(-1),with a diradical character index y0=0.89)for P5Cz^(2+2)·and P5Flu^(2·),respectively.We particularly show in this work a new journey for pillar[5]arenes from the conventionally available closed-shell structures to different open-shell spin states with potential applications in chirospintronics and NIR-active chiroptoelectronic materials.展开更多
π-conjugated chiral macrocycles show fascinating structures and are of interest in synthetic chemistry and material science.Herein,we describe a new series of electron-rich macrocycles that are composed of all-carbaz...π-conjugated chiral macrocycles show fascinating structures and are of interest in synthetic chemistry and material science.Herein,we describe a new series of electron-rich macrocycles that are composed of all-carbazole moieties which can promise the robust structure-dependent redox chemistry.Controlled synthesis of the nearly planar MC[4]was selectively obtained either by a[3+1]or[2+2]coupling reaction of carbazole units.In contrast,stitching of the carbazole trimers via the tetrafunctional bicarbazole linkers gave rise to the rarely accessible biscyclic systems,such as BMC[4]and the chiral C-BMC[4]with a unique figure-eight conformation.The electron-rich nature in their neutral states enables a facile transformation under chemical and electrochemical conditions to the positively charged polycationic states with multispin open-shell characters.Interestingly,the tetracation MC[4]^(4+)is predicted to exhibit global aromaticity due to charge delocalization,and the CD spectra of chiral species C-BMC[4]^(4+4•)are shifted far into the NIR-II up to∼2200 nm.This work provides a fundamental step toward the novel synthesis of electron-rich chiral macrocycles followed by highly charged polycyclophanes with potential applications in chirospintronics and NIR-active optoelectronic materials.展开更多
基金the National Natural Science Foundation of China(Nos.22471014 and 22271013)the Beijing Natural Science Foundation(No.2232024)for financial support.
文摘Fast,precise structure determination of unknown compounds has been the foundation but with a persistent challenge in the field of chemical research.Among various chemical characterization techniques,single-crystal X-ray diffraction(SCXRD)stands out as the most straightforward and accurate method in modern structural chemistry.By precisely determining the three-dimensional arrangement of atoms within a crystal,it provides direct atomic-level evidence for understanding the relationship between material structure and properties[1].
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.
基金supported by the National Natural Science Foundation of China(22471014,22271013)。
文摘Open-shell chiral diradicals that feature both the unique chiroptical properties and tunable spin states have kindled numerous interests in organic synthesis and material science.We present a new class of such model systems based on theπ-extended planar chiral pillar[5]arene derivatives P5Flu and P5Cz,where the pillar[5]arene-based chiral scaffolds are coupled with sterically encumbered fluorenyl and carbazolyl moieties as highly luminescent redox-active emitters,respectively.Both molecules in neutral states can readily undergo chemical oxidations leading toπ-conjugated chiral diradicals of the dehydrogenated P5Flu^(2·)and a positively charged dication P5Cz^(2+2)·.Characterization of the resulting Müller’s open-shell species by variable-temperature electron spin resonance(VT-ESR),UV-vis-NIR absorption,VT-NMR and by computational studies revealed a singlet(ΔE_(S-T)=-1.63 kcal mol^(-1))and a nearly degenerate singlet-triplet ground state(ΔE_(S-T)=0.05 kcal mol^(-1),with a diradical character index y0=0.89)for P5Cz^(2+2)·and P5Flu^(2·),respectively.We particularly show in this work a new journey for pillar[5]arenes from the conventionally available closed-shell structures to different open-shell spin states with potential applications in chirospintronics and NIR-active chiroptoelectronic materials.
基金financially supported by National Natural Science Foundation of China(grant nos.22471014,22271013,and 21772012)Beijing Natural Science Foundation(grant no.2232024).
文摘π-conjugated chiral macrocycles show fascinating structures and are of interest in synthetic chemistry and material science.Herein,we describe a new series of electron-rich macrocycles that are composed of all-carbazole moieties which can promise the robust structure-dependent redox chemistry.Controlled synthesis of the nearly planar MC[4]was selectively obtained either by a[3+1]or[2+2]coupling reaction of carbazole units.In contrast,stitching of the carbazole trimers via the tetrafunctional bicarbazole linkers gave rise to the rarely accessible biscyclic systems,such as BMC[4]and the chiral C-BMC[4]with a unique figure-eight conformation.The electron-rich nature in their neutral states enables a facile transformation under chemical and electrochemical conditions to the positively charged polycationic states with multispin open-shell characters.Interestingly,the tetracation MC[4]^(4+)is predicted to exhibit global aromaticity due to charge delocalization,and the CD spectra of chiral species C-BMC[4]^(4+4•)are shifted far into the NIR-II up to∼2200 nm.This work provides a fundamental step toward the novel synthesis of electron-rich chiral macrocycles followed by highly charged polycyclophanes with potential applications in chirospintronics and NIR-active optoelectronic materials.
