Molecular assembly is typically viewed as a stepwise process from lower-to higher-order structures.Here,we uncovered an alternative kinetic pathway in the cucurbit[8]uril(CB[8])-mediated assembly,where a transient qua...Molecular assembly is typically viewed as a stepwise process from lower-to higher-order structures.Here,we uncovered an alternative kinetic pathway in the cucurbit[8]uril(CB[8])-mediated assembly,where a transient quaternary(2:2)complex formed before the thermodynamically favored ternary(2:1)product.Stopped-flow spectroscopy and structural analysis confirmed the 2:2 intermediate,which formed 36-fold faster than the direct 1:1→2:1 pathway at 298 K.The system thus accumulated in the 2:2 state before relaxing to the 2:1 product.These findings revise the conventional binary-to-ternary model and highlight the mechanistic relevance of higher-order intermediates.It also refines our understanding of apparent cooperativity within a complex assembly network.Recognizing such kinetic complexity opens new avenues for dynamic control in the design of high-performance functional and structural materials.展开更多
基金financially supported by the National Key R&DProgramof China(grant no.2021YFA1501600,G.W.)the National Natural Science Foundation of China(grant nos.22171103 for G.W.and 22301010 for Y.S.)+1 种基金the Natural Science Foundation of Jilin Province,China(grant no.***202301002,G.W.)This work was carried out with the support of the Shanghai Synchrotron Radiation Facility,beamline BL17B,China(proposal 2023-NFPS-PT-500640).
文摘Molecular assembly is typically viewed as a stepwise process from lower-to higher-order structures.Here,we uncovered an alternative kinetic pathway in the cucurbit[8]uril(CB[8])-mediated assembly,where a transient quaternary(2:2)complex formed before the thermodynamically favored ternary(2:1)product.Stopped-flow spectroscopy and structural analysis confirmed the 2:2 intermediate,which formed 36-fold faster than the direct 1:1→2:1 pathway at 298 K.The system thus accumulated in the 2:2 state before relaxing to the 2:1 product.These findings revise the conventional binary-to-ternary model and highlight the mechanistic relevance of higher-order intermediates.It also refines our understanding of apparent cooperativity within a complex assembly network.Recognizing such kinetic complexity opens new avenues for dynamic control in the design of high-performance functional and structural materials.
