title: Observing Single Molecules Complexing with Cucurbit[7]uril through Nanogap Surface-Enhanced Raman Spectroscopy.
abstract: In recent years, single-molecule sensitivity achievable by surface-enhanced Raman spectroscopy (SERS) has been widely reported. We use this to investigate supramolecular host-guest chemistry with the macrocyclic host cucurbit[7]uril, on a few-to-single-molecule level. A nanogap geometry, comprising individual gold nanoparticles on a planar gold surface spaced by a single layer of molecules, gives intense SERS signals. Plasmonic coupling between the particle and the surface leads to strongly enhanced optical fields in the gap between them, with single-molecule sensitivity established using a modification of the well-known bianalyte method. Changes in the Raman modes of the host molecule are observed when single guests included inside its cavity internally stretch it. Anisotropic intermolecular interactions with the guest are found which show additional distinct features in the Raman modes of the host molecule.
authors.affiliation: Nanophotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K.
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Sigle
authors.affiliation: Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Cambridge CB2 1EW, U.K.
authors.forename: Setu
authors.initials: S
authors.lastname: Kasera
authors.affiliation: Nanophotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K.
authors.forename: Lars O
authors.initials: LO
authors.lastname: Herrmann
authors.affiliation: Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Cambridge CB2 1EW, U.K.
authors.forename: Aniello
authors.initials: A
authors.lastname: Palma
authors.affiliation: Nanophotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K.
authors.forename: Bart
authors.initials: B
authors.lastname: de Nijs
authors.affiliation: Nanophotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K.
authors.forename: Felix
authors.initials: F
authors.lastname: Benz
authors.affiliation: Nanophotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K.
authors.forename: Sumeet
authors.initials: S
authors.lastname: Mahajan
authors.affiliation: Nanophotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K.
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Baumberg
authors.affiliation: Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Cambridge CB2 1EW, U.K.
authors.forename: Oren A
authors.initials: OA
authors.lastname: Scherman
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry; D053768:Metal Nanoparticles; D036103:Nanotechnology; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D001952:Bridged-Ring Compounds; D006046:Gold; D007093:Imidazoles; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils