Photodynamic therapy(PDT)holds significant promise as a medical treatment approach in human diseases.Recently,PDT has received attention to harness light-induced reactive oxygen species and,subsequently,modify amyloid...Photodynamic therapy(PDT)holds significant promise as a medical treatment approach in human diseases.Recently,PDT has received attention to harness light-induced reactive oxygen species and,subsequently,modify amyloidogenic peptides implicated in human degenerative diseases.Here we report a series of strategically designed photosensitizers comprised of boron-dipyrromethene(BODIPY)scaffolds conjugated with transition metal ions.Our comprehensive biophysical and biochemical investigations demonstrate the efficacy of the photosensitizers in generating reactive oxygen species(ROS),such as singlet oxygen(^(1)O_(2)),superoxide anion radicals(O_(2)^(·-)),and hydroxyl radicals(·OH),upon photoactivation at a relatively longer wavelength,resulting in the oxidation of amyloid-β(Aβ).Consequently,the induced oxidation brings about significant alterations in the aggregation pathways and morphologies of the peptides.Moreover,Aβspecies produced by treating the metal complex,Ir-BDP,exhibiting the highest ROS generation efficiency and photoactivation,are less toxic than the complex-free Aβspecies.Overall,our findings underscore the therapeutic potential of these newly designed photosensitizers in addressing amyloid-related diseases.展开更多
A series of acyclic aminooxycarbene(AAOC)-ligated ruthenium metathesis catalysts was developed for the ethenolysis of methyl oleate and cis-cyclooctene.AAOC pro-ligands were conveniently synthesized via a one-pot and ...A series of acyclic aminooxycarbene(AAOC)-ligated ruthenium metathesis catalysts was developed for the ethenolysis of methyl oleate and cis-cyclooctene.AAOC pro-ligands were conveniently synthesized via a one-pot and multigram-scale reaction,and the resulting AAOC–Ru catalysts exhibited outstanding catalytic efficiencies(turnover numbers(TONs)of 100000 for methyl oleate and 89000 for cis-cyclooctene)and excellent selectivities(up to 98%).The AAOC ligands possess an ambiphilic character,with both strongσ-donors andπ-acceptors.Notably,combining the strong donating ability and the unsymmetrical structure of AAOC ligands could contribute to the enhancement of the catalytic activity and selectivity of the ruthenium catalysts.This result represents a rare example of acyclic carbene–ruthenium catalysts demonstrating high catalytic efficiency and excellent selectivity in olefin metathesis reactions.展开更多
An approach to enhance the thermally activated delayed fluorescence (TADF) of nido-carborane-appended triarylboranes is proposed.A methyl group is introduced into the 4-position of the phenylene ring bearing the nido-...An approach to enhance the thermally activated delayed fluorescence (TADF) of nido-carborane-appended triarylboranes is proposed.A methyl group is introduced into the 4-position of the phenylene ring bearing the nido-carborane (7,8-dicarba-nido-undecaborane) cage,i.e.,at the ortho position to the cage,in the PhBMes2acceptor moiety of nido-carborane–triarylborane dyads (nido-1–4).The crystal structure of 8-H substituted nido-1 reveals the existence of steric congestion around the cage,resulting in a highly twisted connectivity between the cage plane and the Ph ring (θ=85.7°).All compounds with different 8-R groups (R=H,Me,iPr) exhibit strong TADF with long emission lifetimes (τ_(d)=4.8–9.7 μs in THF) in both THF and PMMA films,which is supported by a very small singlet–triplet energy splitting (ΔE_(ST)< 0.03 eV).Attaching an additional Me group to the ortho position of the BMes2group further enhances the intensity of delayed fluorescence (nido-4).Theoretical studies show that although nido-1–4 reach their local energy minima in a perpendicular arrangement between the cage plane and the Ph ring,there exist large energy barriers to cage rotation.In contrast,the reference compound lacking a 4-Me group,which exhibits very weak delayed fluorescence in solution,has low rotational energy barriers.展开更多
Precise control over the emissive excited states of luminophores is crucial for advancing high-performance optoelectronic materials.Herein,we present a facile strategy for tuning the emissive excited states of o-carbo...Precise control over the emissive excited states of luminophores is crucial for advancing high-performance optoelectronic materials.Herein,we present a facile strategy for tuning the emissive excited states of o-carborane-functionalized B,N-doped multi-resonance thermally activated delayed fluorescence(MR-TADF)compounds through steric modulation of 2-R substituents.A series of 2-R-o-carboranyl MR-TADF compounds,denoted DtBuCzB-CBR,were synthesized and characterized with substituents of varying steric demand at the 2-position of the o-carborane cage(R=H(1),Me(2),iBu(3),and SiMe3(TMS,4)).Single-crystal X-ray analyses of compounds 2 and 4 revealed a nearly perpendicular orientation of the o-carboranyl C-C bond relative to the MR core plane,with compound 4 showing greater C-C bond elongation and structural distortion than 2.Notably,the compounds exhibit either single(1)or dual emission(2-4)in both solution and rigid states,depending on the steric bulk of the 2-R substituent.Theoretical calculations suggest that the single emission originates from a locally excited short-range charge transfer(SRCT)state confined within the MR core,whereas dual emission arises from both the SRCT state and a lower-energy hybridized local and charge transfer(HLCT)state,facilitated by electronic coupling between the MR core and the o-carborane unit.The emergence and persistence of the emissive HLCT state correlate with increased steric hindrance at the 2-position,which induces elongation of the o-carboranyl C-C bond and restricts cage rotation in the excited state.These findings provide a new design principle for o-carborane-based luminophores with tunable excited-state emission characteristics.展开更多
基金work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government[NRF-2022R1I1A1A01064065(G.G.)NRF-2022R1A3B1077319(M.H.L.)+2 种基金NRF-2021R1A2C1011731(C.Y.L.)NRF-2022R1A2C1011793(Y.-H.L.)]the Sejong Science Fellowship Grants(RS-2023-00214034).
文摘Photodynamic therapy(PDT)holds significant promise as a medical treatment approach in human diseases.Recently,PDT has received attention to harness light-induced reactive oxygen species and,subsequently,modify amyloidogenic peptides implicated in human degenerative diseases.Here we report a series of strategically designed photosensitizers comprised of boron-dipyrromethene(BODIPY)scaffolds conjugated with transition metal ions.Our comprehensive biophysical and biochemical investigations demonstrate the efficacy of the photosensitizers in generating reactive oxygen species(ROS),such as singlet oxygen(^(1)O_(2)),superoxide anion radicals(O_(2)^(·-)),and hydroxyl radicals(·OH),upon photoactivation at a relatively longer wavelength,resulting in the oxidation of amyloid-β(Aβ).Consequently,the induced oxidation brings about significant alterations in the aggregation pathways and morphologies of the peptides.Moreover,Aβspecies produced by treating the metal complex,Ir-BDP,exhibiting the highest ROS generation efficiency and photoactivation,are less toxic than the complex-free Aβspecies.Overall,our findings underscore the therapeutic potential of these newly designed photosensitizers in addressing amyloid-related diseases.
基金supported by the Technology Development Program to Solve Climate Changes through the National Research Foundation(NRF)funded by the Ministry of Science,ICT&Future Planning(NRF-2017M1A2A2049102)supported by“Nobel Research Project”grant of the Grubbs Center for Polymers and Catalysis funded by the GIST in 2020.The authors thank Dr Che-Sin Lee at the Gwangju Institute of Science and Technology(GIST)Central Research Facilities for elemental analysis.
文摘A series of acyclic aminooxycarbene(AAOC)-ligated ruthenium metathesis catalysts was developed for the ethenolysis of methyl oleate and cis-cyclooctene.AAOC pro-ligands were conveniently synthesized via a one-pot and multigram-scale reaction,and the resulting AAOC–Ru catalysts exhibited outstanding catalytic efficiencies(turnover numbers(TONs)of 100000 for methyl oleate and 89000 for cis-cyclooctene)and excellent selectivities(up to 98%).The AAOC ligands possess an ambiphilic character,with both strongσ-donors andπ-acceptors.Notably,combining the strong donating ability and the unsymmetrical structure of AAOC ligands could contribute to the enhancement of the catalytic activity and selectivity of the ruthenium catalysts.This result represents a rare example of acyclic carbene–ruthenium catalysts demonstrating high catalytic efficiency and excellent selectivity in olefin metathesis reactions.
基金supported by the Basic Science Research Program funded by the Ministry of Science and ICT(NRF-2019R1A2C1084952 for M.H.Lee and NRF-2018R1A2B6006320 for S.U.Lee)through the National Research Foundation of Korea(NRF).
文摘An approach to enhance the thermally activated delayed fluorescence (TADF) of nido-carborane-appended triarylboranes is proposed.A methyl group is introduced into the 4-position of the phenylene ring bearing the nido-carborane (7,8-dicarba-nido-undecaborane) cage,i.e.,at the ortho position to the cage,in the PhBMes2acceptor moiety of nido-carborane–triarylborane dyads (nido-1–4).The crystal structure of 8-H substituted nido-1 reveals the existence of steric congestion around the cage,resulting in a highly twisted connectivity between the cage plane and the Ph ring (θ=85.7°).All compounds with different 8-R groups (R=H,Me,iPr) exhibit strong TADF with long emission lifetimes (τ_(d)=4.8–9.7 μs in THF) in both THF and PMMA films,which is supported by a very small singlet–triplet energy splitting (ΔE_(ST)< 0.03 eV).Attaching an additional Me group to the ortho position of the BMes2group further enhances the intensity of delayed fluorescence (nido-4).Theoretical studies show that although nido-1–4 reach their local energy minima in a perpendicular arrangement between the cage plane and the Ph ring,there exist large energy barriers to cage rotation.In contrast,the reference compound lacking a 4-Me group,which exhibits very weak delayed fluorescence in solution,has low rotational energy barriers.
基金supported by the Basic Science Research Program funded by the Ministry of Science and ICT(MSIT)(RS-2025-00514431 and RS-2025-02216980 for M.H.L.and NRF-2021R1A2C1009191 and RS-2024-00407859 for J.J.)through the National Research Foundation of Korea(NRF)financial support from the Ulsan RISE Center(2025-RISE-07-001).
文摘Precise control over the emissive excited states of luminophores is crucial for advancing high-performance optoelectronic materials.Herein,we present a facile strategy for tuning the emissive excited states of o-carborane-functionalized B,N-doped multi-resonance thermally activated delayed fluorescence(MR-TADF)compounds through steric modulation of 2-R substituents.A series of 2-R-o-carboranyl MR-TADF compounds,denoted DtBuCzB-CBR,were synthesized and characterized with substituents of varying steric demand at the 2-position of the o-carborane cage(R=H(1),Me(2),iBu(3),and SiMe3(TMS,4)).Single-crystal X-ray analyses of compounds 2 and 4 revealed a nearly perpendicular orientation of the o-carboranyl C-C bond relative to the MR core plane,with compound 4 showing greater C-C bond elongation and structural distortion than 2.Notably,the compounds exhibit either single(1)or dual emission(2-4)in both solution and rigid states,depending on the steric bulk of the 2-R substituent.Theoretical calculations suggest that the single emission originates from a locally excited short-range charge transfer(SRCT)state confined within the MR core,whereas dual emission arises from both the SRCT state and a lower-energy hybridized local and charge transfer(HLCT)state,facilitated by electronic coupling between the MR core and the o-carborane unit.The emergence and persistence of the emissive HLCT state correlate with increased steric hindrance at the 2-position,which induces elongation of the o-carboranyl C-C bond and restricts cage rotation in the excited state.These findings provide a new design principle for o-carborane-based luminophores with tunable excited-state emission characteristics.
