Pillar[5]arene-based molecular universal joints(MUJs), bearing fused crown ether subring(MUJ1 and MUJ3) or a ring without ether oxygen atom(MUJ2), were synthesized and enantio–differentiated. Significant chiral inver...Pillar[5]arene-based molecular universal joints(MUJs), bearing fused crown ether subring(MUJ1 and MUJ3) or a ring without ether oxygen atom(MUJ2), were synthesized and enantio–differentiated. Significant chiral inversion was observed for the crown ether-fused MUJs upon the addition of equivalent cations Na+, showing an anisotropy(g) factor of 0.014, while alkyl subring-fused MUJ2 showed no CD inversions. Unprecedentedly, sodium ion triggered rolling-in motion of the subring to the pillar[5]arene cavity was verified, and the synergistic noncovalent interaction of cation-π interactions and C–H···π interactions were responsible for the stabilized self-included conformers. The addition of Me OH or competitive hosts 15-crown-5 ether disassembled the complex of MUJ1 and Na+followed by a rolling-out of the subring, which made the sodium-ion triggered chiroptical switching reversible.展开更多
Achieving room temperature phosphorescence(RTP)of heavy-atom-free organic molecules with near-infrared(NIR)emission in solutions is fascinating for medical and biological applications but is highly challengable.Herein...Achieving room temperature phosphorescence(RTP)of heavy-atom-free organic molecules with near-infrared(NIR)emission in solutions is fascinating for medical and biological applications but is highly challengable.Herein,we report a new sensitization strategy to achieve RTP of heavy-atom-free fluorophores which served as energy acceptors in triplet-triplet annihilation upconversion(TTA-UC)by carefully designing the accommodated microenvironments through non-covalent interactions with a PAMAM dendrimer matrix.Sensitized RTP of a serial of diphenyl anthracene(DPA)derivatives peaked at 766 nm were observed for the first time in an aqueous solution with a maximal quantum yield of 1.4%.A ternary supramolecular assembling between the UC components and the dendrimers was formed via electrostatic interaction between the–COOH and peripheral amino groups.On one hand,it assured the efficient population of the triplet states of the fluorophore via triplet-triplet energy transfer(TTET)process;on the other hand,it restricted the motions of the fluorophores,and thus inhibited the nonradiative inactivation of the populated triplet states.These two aspects jointly contributed to the sensitized RTP of DPA units.Significantly,the microenvironment in which the annihilators resided could be regulated by adjusting the ratio of carboxyl to amino groups(–COOH/–NH_(2)),when–COOH/–NH_(2)<1,the annihilators were mainly immobilized at the periphery of the dendrimers,leading to the sensitized RTP,and when COOH/–NH_(2)>1,the UC components could be partly driven to the hydrophobic cavities of the dendrimers,resulting an unprecedentedly simultaneous emission of upconverted fluorescence and down-converted phosphorescence of the annihilators.展开更多
基金the support of this work by the National Natural Science Foundation of China (Nos. 22171194, 21971169, 92056116, 21871194)the Science & Technology Department of Sichuan Province (Nos. 2022YFH0095, 2021ZYD0052)。
文摘Pillar[5]arene-based molecular universal joints(MUJs), bearing fused crown ether subring(MUJ1 and MUJ3) or a ring without ether oxygen atom(MUJ2), were synthesized and enantio–differentiated. Significant chiral inversion was observed for the crown ether-fused MUJs upon the addition of equivalent cations Na+, showing an anisotropy(g) factor of 0.014, while alkyl subring-fused MUJ2 showed no CD inversions. Unprecedentedly, sodium ion triggered rolling-in motion of the subring to the pillar[5]arene cavity was verified, and the synergistic noncovalent interaction of cation-π interactions and C–H···π interactions were responsible for the stabilized self-included conformers. The addition of Me OH or competitive hosts 15-crown-5 ether disassembled the complex of MUJ1 and Na+followed by a rolling-out of the subring, which made the sodium-ion triggered chiroptical switching reversible.
基金supported by the National Natural Science Foundation of China(22171194,21971169,92056116,21871194,21572142)the Science&Technology Department of Sichuan Province(2022YFH0095,2021ZYD0052)the Fundamental Research Funds for the Central Universities(20826041D4117)。
文摘Achieving room temperature phosphorescence(RTP)of heavy-atom-free organic molecules with near-infrared(NIR)emission in solutions is fascinating for medical and biological applications but is highly challengable.Herein,we report a new sensitization strategy to achieve RTP of heavy-atom-free fluorophores which served as energy acceptors in triplet-triplet annihilation upconversion(TTA-UC)by carefully designing the accommodated microenvironments through non-covalent interactions with a PAMAM dendrimer matrix.Sensitized RTP of a serial of diphenyl anthracene(DPA)derivatives peaked at 766 nm were observed for the first time in an aqueous solution with a maximal quantum yield of 1.4%.A ternary supramolecular assembling between the UC components and the dendrimers was formed via electrostatic interaction between the–COOH and peripheral amino groups.On one hand,it assured the efficient population of the triplet states of the fluorophore via triplet-triplet energy transfer(TTET)process;on the other hand,it restricted the motions of the fluorophores,and thus inhibited the nonradiative inactivation of the populated triplet states.These two aspects jointly contributed to the sensitized RTP of DPA units.Significantly,the microenvironment in which the annihilators resided could be regulated by adjusting the ratio of carboxyl to amino groups(–COOH/–NH_(2)),when–COOH/–NH_(2)<1,the annihilators were mainly immobilized at the periphery of the dendrimers,leading to the sensitized RTP,and when COOH/–NH_(2)>1,the UC components could be partly driven to the hydrophobic cavities of the dendrimers,resulting an unprecedentedly simultaneous emission of upconverted fluorescence and down-converted phosphorescence of the annihilators.
