Spirothiopyran(STP)is particularly attractive when used as a mechanophore to endow polymers with both damage-signaling and.self-reinforcing capacity.It is,however,not clear the actual force required to induce the cycl...Spirothiopyran(STP)is particularly attractive when used as a mechanophore to endow polymers with both damage-signaling and.self-reinforcing capacity.It is,however,not clear the actual force required to induce the cycloreversion of STP into ring-opened thiomerocyanine(TMC),which reacts spontaneously with activated C=C bonds.Here,we used atomic force microscopy(AFM)-based single molecule force spectroscopy(SMFS)to study the mechanochemistry of STP mechanophore.It is found that the ring-opening of STP at room temperature requires forces of-200-400 pN,depending on the pulling speed.In addition,the reversibility of STP to TMC isomerization is demonstrated.Finally,mechanochemically induced intermolecular Click addition is achieved in single'molecule level by pulling STP in the presence of maleimide.展开更多
Spiropyran derivatives are prototype mechanophores with a promising application as molecular sensors because of their changeable structure under external force stimuli.However,the chemical structure evolution under ex...Spiropyran derivatives are prototype mechanophores with a promising application as molecular sensors because of their changeable structure under external force stimuli.However,the chemical structure evolution under external stimuli remains unclear due to the uncertainty and difficulty in distinguishing the structures of different ring-opened merocyanine isomers generated in the force-induced reaction.Here we identify the structure of isomers produced by the force-induced reaction of spiropyran derivatives using a single-molecule conductance measurement and an unsupervised clustering algorithm.We found that the original data from the single-molecule conductance measurement can be divided into four clusters through unsupervised clustering.By introducing a photoinduced reaction and theoretical calculation,we identified and attributed the four clusters of data to the multiple states of the molecular junctions.Our work demonstrates that a single-molecule break junction measurement can distinguish the isomers in the force-induced reaction,suggesting the great potential of single-molecule conductance measurement and unsupervised clustering approaches for structural analysis.展开更多
基金funded by the National Natural Science Foundation of China((Nos.21525418 and 21827805)(W.Z.),(Nos.21774106 and 21574108)(W.W.)).
文摘Spirothiopyran(STP)is particularly attractive when used as a mechanophore to endow polymers with both damage-signaling and.self-reinforcing capacity.It is,however,not clear the actual force required to induce the cycloreversion of STP into ring-opened thiomerocyanine(TMC),which reacts spontaneously with activated C=C bonds.Here,we used atomic force microscopy(AFM)-based single molecule force spectroscopy(SMFS)to study the mechanochemistry of STP mechanophore.It is found that the ring-opening of STP at room temperature requires forces of-200-400 pN,depending on the pulling speed.In addition,the reversibility of STP to TMC isomerization is demonstrated.Finally,mechanochemically induced intermolecular Click addition is achieved in single'molecule level by pulling STP in the presence of maleimide.
基金supported by the National Natural Science Foundation of China(grant nos.22173075,21933012,61901402,31871877,and 21774106)the National Key R&D Program of China(grant no.2017YFA0204902)+1 种基金the Fundamental Research Funds for the Central Universities(grant nos.20720200068 and 20720190002)the Natural Science Foundation of Fujian Province(grant no.2018J06004).
文摘Spiropyran derivatives are prototype mechanophores with a promising application as molecular sensors because of their changeable structure under external force stimuli.However,the chemical structure evolution under external stimuli remains unclear due to the uncertainty and difficulty in distinguishing the structures of different ring-opened merocyanine isomers generated in the force-induced reaction.Here we identify the structure of isomers produced by the force-induced reaction of spiropyran derivatives using a single-molecule conductance measurement and an unsupervised clustering algorithm.We found that the original data from the single-molecule conductance measurement can be divided into four clusters through unsupervised clustering.By introducing a photoinduced reaction and theoretical calculation,we identified and attributed the four clusters of data to the multiple states of the molecular junctions.Our work demonstrates that a single-molecule break junction measurement can distinguish the isomers in the force-induced reaction,suggesting the great potential of single-molecule conductance measurement and unsupervised clustering approaches for structural analysis.
