Interfacial host–guest complexation offers a versatile way to functionalize nanomaterials.However,the complicated interfacial environment and trace amounts of components present at the interface make the study of int...Interfacial host–guest complexation offers a versatile way to functionalize nanomaterials.However,the complicated interfacial environment and trace amounts of components present at the interface make the study of interfacial complexation very difficult.Herein,taking the advantages of near-single-molecule level sensitivity and molecular fingerprint of surface-enhanced Raman spectroscopy(SERS),we reveal that a cooperative effect between cucurbit[7]uril(CB[7])and methyl viologen(MV^(2+)2^(I−))in aggregating Au NPs originates from the cooperative adsorption of halide counter anions I^(−),MV^(2+),and CB[7]on Au NPs surface.Moreover,similar SERS peak shifts in the control experiments using CB[n]s but with smaller cavity sizes suggested the occurrence of the same guest complexations among CB[5],CB[6],and CB[7]with MV2+.Hence,an unconventional exclusive complexation model is proposed between CB[7]and MV^(2+)on the surface of Au NPs,distinct from the well-known 1:1 inclusion complexation model in aqueous solutions.In summary,new insights into the fundamental understanding of host–guest interactions at nanostructured interfaces were obtained by SERS,which might be useful for applications related to host–guest chemistry in engineered nanomaterials.展开更多
基金This work was financially supported by the NSFC(no.41876099,91427304,91227111,21722304,and 21971216)the Xiamen Science and Technology Project(no.3502Z20183002).
文摘Interfacial host–guest complexation offers a versatile way to functionalize nanomaterials.However,the complicated interfacial environment and trace amounts of components present at the interface make the study of interfacial complexation very difficult.Herein,taking the advantages of near-single-molecule level sensitivity and molecular fingerprint of surface-enhanced Raman spectroscopy(SERS),we reveal that a cooperative effect between cucurbit[7]uril(CB[7])and methyl viologen(MV^(2+)2^(I−))in aggregating Au NPs originates from the cooperative adsorption of halide counter anions I^(−),MV^(2+),and CB[7]on Au NPs surface.Moreover,similar SERS peak shifts in the control experiments using CB[n]s but with smaller cavity sizes suggested the occurrence of the same guest complexations among CB[5],CB[6],and CB[7]with MV2+.Hence,an unconventional exclusive complexation model is proposed between CB[7]and MV^(2+)on the surface of Au NPs,distinct from the well-known 1:1 inclusion complexation model in aqueous solutions.In summary,new insights into the fundamental understanding of host–guest interactions at nanostructured interfaces were obtained by SERS,which might be useful for applications related to host–guest chemistry in engineered nanomaterials.
