Chapter 5 Modeling molecular switches: a flexible molecule anchored to a surface

Abstract

Publisher Summary This chapter reviews molecular switches, focusing mainly on the conductance switching systems. Switches are the most basic components of an electronic circuit. A molecular switch is a nanoscale machine that switches reversibly between two or more states. Many molecules have different conformational or electronic states depending on its external conditions; such molecules are very promising candidates for the design and synthesis of molecular switches. A structural change of a molecule is analogous to the mechanical motion of a macroscopic system. Nanoprobes such as scanning tunneling microscope (STM) and atomic force microscope (AFM) are powerful tools for the manipulation of a molecule adsorbed on surfaces using local forces. The design of a reversible molecular switch based on a polar amide molecule on surface is appropriate for conductance studies done by using STM. Molecular scale mechanical switching based on interlocked molecules mainly including rotaxanes and catenanes are investigated in the chapter. These interlocked systems generally consist of an electron-rich and an electron-deficient portion held together by non-covalent bonds.