Photon-Gated Electron Transfer in Two-Component Self-Assembled Monolayers
摘要:
The preparation and characterization of a photoactive, two-component self-assembled monolayer (SAM) consisting of 99:1 cis-p-(C6H5)N=N(C6H4)O(CH2)(11)SH) (1) and trans-p,p-Fc(C6H4)N=N(C6H4)(CH2)(4)SH (Fc = C5H4FeC5H5; 2) are reported. With this SAM, electron transfer between solution ferrocyanide and the Au substrate is forced to occur through mediating ferrocenyl sites in the film, resulting in a diode-like response. However, by photochemically converting large "footprint" cis-l to the smaller footprint trans-1, the free volume within the film is increased, thereby allowing for direct electron transfer between the solution ferrocyanide and the electrode surface and a normal electrochemical response (i.e. i(pa) = i(pc)). All states of the film have been characterized by cyclic voltammetry, FTIR spectroscopy, and differential capacitance measurements. All data from these techniques are consistent with the conclusion that cis-trans azobenzene isomerization within the monolayer results in increased film porosity, which reduces the film's ability to block the access of solution redox-active species to the underlying Au electrode surface. This novel two-component structure establishes the concept for a new type of molecule-based electronic device, a "photoswitchable diode" that is capable of amplifying the signal associated with a photodriven event via an electrochemical response. With such a system, a small number of photons can release a relatively large number of electrons from the solution electron reservoir. Significantly, this system shows how one can regulate electron-transfer events involving SAMs through photochemical control over film structure and free volume.
This disclosure concerns novel compounds of Formula (I) as defined in the specification and compositions comprising such novel compounds. These compounds are useful antiviral agents, especially in inhibiting the function of the NS5A protein encoded by Hepatitis C virus (HCV). Thus, the disclosure also concerns a method of treating HCV related diseases or conditions by use of these novel compounds or a composition comprising such novel compounds.
Writing Self-Erasing Images using Metastable Nanoparticle “Inks”
作者:Rafal Klajn、Paul J. Wesson、Kyle J. M. Bishop、Bartosz A. Grzybowski
DOI:10.1002/anie.200901119
日期:2009.9.7
Mission Impossible: Metal nanoparticles (NPs) coated with photoresponsive ligands are used as “inks” for self‐erasing “paper” whereby light‐induced self‐assembly of the NPs is transduced into local color changes (see picture). Depending on the degree of self‐assembly, multicolor images can be written using only one type of NP ink. Duration of image erasure is regulated by the surface concentration
Structure of Alkyl and Perfluoroalkyl Disulfide and Azobenzenethiol Monolayers on Gold(111) Revealed by Atomic Force Microscopy
作者:M. Jaschke、H. Schönherr、H. Wolf、H.-J. Butt、E. Bamberg、M. K. Besocke、H. Ringsdorf
DOI:10.1021/jp952355o
日期:1996.1.1
The structure of various self-assembled thiol and disulfide monolayers on gold(111) has been studied with the atomic force microscope. The aim was to analyze the factors which determine the two-dimensional structure of the molecules. Monolayers were formed from different disulfides and thiols: long-chain alkyl and perfluoroalkyl esters of bis(2-hydroxyethyl) disulfide, several azobenzenethiols, and octadecanethiol. Three classes of two-dimensional structures could be distinguished: (1) commensurate monolayers, which were dominated by the underlying gold(111) lattice; an example is n-alkanethiol monolayers; (2) incommensurate or at most high-order commensurate monolayers, whose orientation was still determined by the gold(111) substrate; this type of monolayer probably occurred with all disulfides investigated; (3) incommensurate monolayers, whose orientation was arbitrary and not determined by the underlying gold(111). Monolayers of azobenzenthiols belonged to this class.
Metastable Nanoparticle Ink Compositions and Images Made Therefrom
申请人:Grzybowski Bartosz A.
公开号:US20100328410A1
公开(公告)日:2010-12-30
Self-erasing inks in which both the printing and self-erasure of color images can be controlled by the dynamic/non-equilibrium aggregation of photoresponsive surface-coated nanoparticles contained in a carrier film are provided. The aggregation is a reversible aggregation that is triggered by a photo-induced transformation in ligands within the surface coating on the nanoparticles. Methods for forming images using the inks are also provided.