Diradicaloid polycyclic hydrocarbons(PHs)own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics.Herein,we disclose precise fusion of B/O-heterocy...Diradicaloid polycyclic hydrocarbons(PHs)own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics.Herein,we disclose precise fusion of B/O-heterocycles onto PHs for control over their electronic structures and diradical properties.We designed and synthesized four B/O-containing diradicaloid isomers that feature the fluoreno[3,2-b]fluorene and fluoreno[2,1-a]fluoreneπ-skeletons,respectively.The precise B/O-heterocycle fusion modes along with the changed conjugation patterns lead to their modulated electronic structures and properties,such as diradical and aromatic structures,energy levels and band gaps,as well as magnetic,electrochemical and photophysical properties.Notably,the mode A may decrease the open-shell extent,whereas the mode B can enhance the diradical nature,leading to their well-tuned diradical characters in the range of0.46-0.70.Moreover,the mode A stabilizes the LUMOs and the mode B obviously increases the HOMO levels,which are remarkably contributed by the B and O atoms,respectively,further giving rise to the decreased band gaps and redshifted absorptions.This study clearly illustrates the electronic effects of B/O-heterocycle fusion on PHs and gains insight into B/O-type organic diradicaloids.These findings will provide an important guideline for the design of more fascinating heteroatom-containing diradicaloids.展开更多
Organic singlet diradicaloids are promising photothermal agents owing to their exceptional light-harvesting capabilities and efficient light-to-heat conversion.In this study,two stable dibenzononazethrene isomers,DBNZ...Organic singlet diradicaloids are promising photothermal agents owing to their exceptional light-harvesting capabilities and efficient light-to-heat conversion.In this study,two stable dibenzononazethrene isomers,DBNZ1 and DBNZ2,are synthesized through a concise method and isolated in crystalline form.An open-shell singlet diradical ground state,with diradical indices of 0.67 and 0.69,is confirmed through a combination of theoretical and experimental approaches.Steady-state and time-resolved absorption spectroscopy demonstrated efficient light absorption in the far-red region and excellent light-to-heat conversion,attributed to a rapid nonradiative process.Encapsulation of DBNZ1 with an amphiphilic polymer produced water-dispersible nanoparticles(DBNZ1-NPs)with enhanced stability,achieving an impressive photothermal conversion efficiency of 72.9%.An in vitro photothermal therapy study demonstrated that DBNZ1-NPs functioned as biocompatible tumor ablation agents when activated by an 808 nm laser,highlighting their potential application in cancer photothermal therapy.展开更多
Diradicaloids have garnered significant attention due to their unique electronic,photophysical properties and potential applications in functional materials.Characterized by a narrow band gap and near-infrared(NIR)abs...Diradicaloids have garnered significant attention due to their unique electronic,photophysical properties and potential applications in functional materials.Characterized by a narrow band gap and near-infrared(NIR)absorption,diradicaloids are promising candidates for NIR-guided photothermal therapy.However,they are often unstable and exhibit non-emissive properties due to high chemical reactivity and very efficient internal conversion.Herein,we report a remarkably stable Chichibabin diradicaloid,TT-CzPh,which exhibits NIR luminescence(λ_(em)=821 nm)with an efficient photoluminescence quantum yield(PLQY)of 6.4%.Surprisingly,TT-CzPh not only exhibits excellent NIR imaging but also has a very high photothermal conversion efficiency(PCE)of 87.5%.In vivo experiments with TT-CzPh nanoparticles demonstrated their effectiveness in tumor photoablation guided by NIR imaging.This work not only advances the development of stable,efficient luminescent Chichibabin’s hydrocarbons but also opens new avenues for bioimaging and cancer phototherapy applications.展开更多
Müller's hydrocarbon is a well-known open-shell singlet diradicaloid,yet its structural determination and redox property remain elusive due to its extremely high reactivity.Herein,we report the successful syn...Müller's hydrocarbon is a well-known open-shell singlet diradicaloid,yet its structural determination and redox property remain elusive due to its extremely high reactivity.Herein,we report the successful synthesis and full characterizations of the first neutral boron-centered analogue(4)of Müller's hydrocarbon,along with the first dianionic boron-centered analogue(5^(2−))featuring three isolable redox states.In the presence of two equivalents of N-heterocyclic carbene(NHC),reduction of 4,4”-bis(triisopropylphenylbromoboryl)terphenyl 3 with potassium graphite afforded NHC-stabilized boryl diradicaloid 4 with a near-pure diradical character(y0=0.93).Stepwise reductions of 4,4”-bis(dimesitylboryl)terphenyl 5 in THF yielded the isolable monoradical anion 5·−and diradical dianion 5^(2−),respectively,accompanied by a decreasing aromaticity within the conjugated spacer.Experimental studies and theoretical analyses revealed that both 4 and 5^(2−)exhibit large spin distributions at boron atoms,open-shell singlet ground states,and small singlet-triplet energy gaps.展开更多
Organic diradicaloids with unique open-shell structures and properties have been widely used in organic electronics and spintronics.However,their advantageous optical properties have been explored less in the biomedic...Organic diradicaloids with unique open-shell structures and properties have been widely used in organic electronics and spintronics.However,their advantageous optical properties have been explored less in the biomedical field.In this work,the photothermal conversion behaviors of a boron-containing organic diradicaloid(BOD)are reported.BOD can assemble with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)to form rodlike nanoparticles(BOD NPs).These as-prepared BOD NPs exhibit high photothermal conversion capability and robust photothermal stability.Notably,they possess morphological superiority,which guarantees the effective photothermal therapy of tumors.This work thus demonstrates the promise of organic diradicaloids as efficient photothermal agents for biomedical applications.展开更多
Knowledge about electronic structures is important to gain an understanding of the unique functional properties of diradicaloids.In this study,we synthesized and characterized a diradicaloid in which two phenalenyl ra...Knowledge about electronic structures is important to gain an understanding of the unique functional properties of diradicaloids.In this study,we synthesized and characterized a diradicaloid in which two phenalenyl radical sites are coupled antiferromagnetically via a through-space interaction.The results of quantum chemical,physicochemical(^(1)H NMR,electronic absorption,cyclic voltammetry,SQUID,ESR),and chemical reactivity studies show that this diradicaloid has singlet diradical character.An assessment of the nature of the bonding interaction between two radical sites in this species using DFT calculations demonstrates that a small spatial overlap between the two SOMOs in this diradicaloid provides an efficient electron exchange path for the singlet state to be substantially lower in energy than the triplet state.展开更多
基金supported by National Natural Science Foundation of China(Nos.52373182 and 22175074)Jilin Scientific and Technological Development Program(No.20220101054JC)Department of Education of Jilin Province(No.JJKH20221046KJ)。
文摘Diradicaloid polycyclic hydrocarbons(PHs)own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics.Herein,we disclose precise fusion of B/O-heterocycles onto PHs for control over their electronic structures and diradical properties.We designed and synthesized four B/O-containing diradicaloid isomers that feature the fluoreno[3,2-b]fluorene and fluoreno[2,1-a]fluoreneπ-skeletons,respectively.The precise B/O-heterocycle fusion modes along with the changed conjugation patterns lead to their modulated electronic structures and properties,such as diradical and aromatic structures,energy levels and band gaps,as well as magnetic,electrochemical and photophysical properties.Notably,the mode A may decrease the open-shell extent,whereas the mode B can enhance the diradical nature,leading to their well-tuned diradical characters in the range of0.46-0.70.Moreover,the mode A stabilizes the LUMOs and the mode B obviously increases the HOMO levels,which are remarkably contributed by the B and O atoms,respectively,further giving rise to the decreased band gaps and redshifted absorptions.This study clearly illustrates the electronic effects of B/O-heterocycle fusion on PHs and gains insight into B/O-type organic diradicaloids.These findings will provide an important guideline for the design of more fascinating heteroatom-containing diradicaloids.
基金support from National Natural Science Foundation of China(Grants 22222110 and 22371206)the Haihe Laboratory of Sustainable Chemical Transformations(24HHWCSS00009)the State Key Laboratory of Chemical Oncogenomics,and the Institute of Biomedical Health Technology and Engineering of Shenzhen Bay Laboratory。
文摘Organic singlet diradicaloids are promising photothermal agents owing to their exceptional light-harvesting capabilities and efficient light-to-heat conversion.In this study,two stable dibenzononazethrene isomers,DBNZ1 and DBNZ2,are synthesized through a concise method and isolated in crystalline form.An open-shell singlet diradical ground state,with diradical indices of 0.67 and 0.69,is confirmed through a combination of theoretical and experimental approaches.Steady-state and time-resolved absorption spectroscopy demonstrated efficient light absorption in the far-red region and excellent light-to-heat conversion,attributed to a rapid nonradiative process.Encapsulation of DBNZ1 with an amphiphilic polymer produced water-dispersible nanoparticles(DBNZ1-NPs)with enhanced stability,achieving an impressive photothermal conversion efficiency of 72.9%.An in vitro photothermal therapy study demonstrated that DBNZ1-NPs functioned as biocompatible tumor ablation agents when activated by an 808 nm laser,highlighting their potential application in cancer photothermal therapy.
基金supported by the National Key R&D Program of China(No.2023YFB3208303)the National Natural Science Foundation of China(Grant Nos.62422404,62171194,52103210)the Natural Science Foundation of Jilin Province(No.20230101363JC).
文摘Diradicaloids have garnered significant attention due to their unique electronic,photophysical properties and potential applications in functional materials.Characterized by a narrow band gap and near-infrared(NIR)absorption,diradicaloids are promising candidates for NIR-guided photothermal therapy.However,they are often unstable and exhibit non-emissive properties due to high chemical reactivity and very efficient internal conversion.Herein,we report a remarkably stable Chichibabin diradicaloid,TT-CzPh,which exhibits NIR luminescence(λ_(em)=821 nm)with an efficient photoluminescence quantum yield(PLQY)of 6.4%.Surprisingly,TT-CzPh not only exhibits excellent NIR imaging but also has a very high photothermal conversion efficiency(PCE)of 87.5%.In vivo experiments with TT-CzPh nanoparticles demonstrated their effectiveness in tumor photoablation guided by NIR imaging.This work not only advances the development of stable,efficient luminescent Chichibabin’s hydrocarbons but also opens new avenues for bioimaging and cancer phototherapy applications.
基金support from the National Natural Science Foundation of China(22371197 and 22001184)Natural Science Foundation of Jiangsu Province(BK20200849).
文摘Müller's hydrocarbon is a well-known open-shell singlet diradicaloid,yet its structural determination and redox property remain elusive due to its extremely high reactivity.Herein,we report the successful synthesis and full characterizations of the first neutral boron-centered analogue(4)of Müller's hydrocarbon,along with the first dianionic boron-centered analogue(5^(2−))featuring three isolable redox states.In the presence of two equivalents of N-heterocyclic carbene(NHC),reduction of 4,4”-bis(triisopropylphenylbromoboryl)terphenyl 3 with potassium graphite afforded NHC-stabilized boryl diradicaloid 4 with a near-pure diradical character(y0=0.93).Stepwise reductions of 4,4”-bis(dimesitylboryl)terphenyl 5 in THF yielded the isolable monoradical anion 5·−and diradical dianion 5^(2−),respectively,accompanied by a decreasing aromaticity within the conjugated spacer.Experimental studies and theoretical analyses revealed that both 4 and 5^(2−)exhibit large spin distributions at boron atoms,open-shell singlet ground states,and small singlet-triplet energy gaps.
基金National Natural Science Foundation of China,Grant/Award Numbers:52003267,51973214,22175074Natural Science Foundation of Jilin Province,Grant/Award Numbers:YDZJ202101ZYTS027,20220101054JC。
文摘Organic diradicaloids with unique open-shell structures and properties have been widely used in organic electronics and spintronics.However,their advantageous optical properties have been explored less in the biomedical field.In this work,the photothermal conversion behaviors of a boron-containing organic diradicaloid(BOD)are reported.BOD can assemble with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)to form rodlike nanoparticles(BOD NPs).These as-prepared BOD NPs exhibit high photothermal conversion capability and robust photothermal stability.Notably,they possess morphological superiority,which guarantees the effective photothermal therapy of tumors.This work thus demonstrates the promise of organic diradicaloids as efficient photothermal agents for biomedical applications.
基金the JSPS for KAKENHI funding(Grant No.JP21H01918 and JP20K21194)a Grant-in-Aid for Transformative Research Areas(A)“Condensed Conjugation”(JSPS for KAKENHI funding Grant No.JP20H05865)from MEXT,Japan.
文摘Knowledge about electronic structures is important to gain an understanding of the unique functional properties of diradicaloids.In this study,we synthesized and characterized a diradicaloid in which two phenalenyl radical sites are coupled antiferromagnetically via a through-space interaction.The results of quantum chemical,physicochemical(^(1)H NMR,electronic absorption,cyclic voltammetry,SQUID,ESR),and chemical reactivity studies show that this diradicaloid has singlet diradical character.An assessment of the nature of the bonding interaction between two radical sites in this species using DFT calculations demonstrates that a small spatial overlap between the two SOMOs in this diradicaloid provides an efficient electron exchange path for the singlet state to be substantially lower in energy than the triplet state.
