CONTROLLED ROOM-TEMPERATURE POSITIONING OF INDIVIDUAL MOLECULES - MOLECULAR FLEXURE AND MOTION

Two-dimensional positioning of intact individual molecules was achieve d at room temperature by a controlled lateral ''pushing'' action of th e tip of a scanning tunneling microscope. To facilitate this process, four bulky hydrocarbon groups were attached to a rigid molecule. These groups maintained sufficiently strong interactions with the surface t o prevent thermally activated diffusional motion, but nevertheless all owed controllable translation. Simulations demonstrated the crucial ro le of flexure during the positioning process. These results outline th e key role of molecular mechanics in the engineering of predefined pro perties on a molecular scale.