Fluorescence probes for chemical reactivity at the interface of a self-assembled monolayer

New methods for reversible photoimaging of spatially defined surfaces represent attractive technological applications of thin organized films. Surface immobilization of photoresponsive derivatives of alkanethiols on gold can influence attainable excited state partitioning among competing reaction pathways. Surface fluorescence measurements on such reflective metal surfaces can be used to monitor surface composition when highly emissive molecules are attached to a self-assembled monolayer. These measurements can also be used as a probe for in situ chemical modification of a self-assembled monolayer and for photoreactivity of coumarin- and anthracene-derivatives attached at the end of a variable length tether anchored through an alkyl sulfide onto a smooth polycrystalline gold surface. The observed changes in the fluorescence can be related to local structure and to the unusual environment encountered by the probe molecule within the self-assembled monolayer. (C) 1998 Elsevier Science S.A. All rights reserved.