title: Striking confinement effect: AuCl4(-) binding to amines in a nanocage cavity.
abstract: Binding of AuCl(4)(-) to amine groups tethered to the interior of a 2 nm siloxane nanocage was determined in solutions containing various concentrations of acid. The mode of binding was inferred from EXAFS and UV-vis spectra to be by ligand exchange of amine for chloride, which implies that the amines remain unprotonated. Cyclic voltammetry confirmed that the Au complexes bind to the nanocage interior and established a 1:1 relationship between bound Au complex and amine groups. The results suggested a 5-7 pH unit shift in the protonation constant of the interior amines relative to free amines in solution.
authors.affiliation: Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, E136, Evanston, Illinois 60208-3120, USA.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Henao
authors.forename: Young-Woong
authors.initials: YW
authors.lastname: Suh
authors.forename: Jeong-Kyu
authors.initials: JK
authors.lastname: Lee
authors.forename: Mayfair C
authors.initials: MC
authors.lastname: Kung
authors.forename: Harold H
authors.initials: HH
authors.lastname: Kung