TETRATHIAFULVALENE AND ITS DERIVATIVES AS π-ELECTRON DONATING UNITS IN PSEUDOROTAXANES, ROTAXANES, AND CATENANES

摘要

The in terest for tetrathiafulvalene (hereafter in dicated as TTF) began a bout sevenly years ago, but before 1970 only a few articles appeared in the literature. In 1970 Wudl and coworkers observed that TTF can be reversibly oxidized to monocationic radical and dication; both the charged species are stable in solution for a long time, and the first and second oxidation potential values can be finely tuned by appropriate substituents. Since 1970 the work dealing with TTF has increased enormously. A few years later Ferraris et al. Observed that TTF reacts in the solid state with 7,7',8,8'-tetracyano-p-quinodimethane (a good π-electron accepting unit), forming a molecular-solid, which for its high electrical conductivity and some similarity with metals was named the first organic metal. For its chemical and electrochemical properties TTF (and its derivatives) is today considered an important building block in many fields of scientific research, both in physics and chemistry. TTF has been recently widespreadly used in supramolecular chemistry, a new branch which studies systems constituted by a small number of discrete molecular components, in the same way as combination of atoms leads to molecules. Supramolecular chemistry allows a bottom-up approach towards miniaturization and can lead to the construction of molecular-level devices and machines as an alternative to the top-down one.