ORGN 46 |
| Bistable mechanically interlocked compounds have demonstrated their usefulness as the active components in molecular electronics and nanoelectromechanical devices.1 As a result, many structural motifs are being investigated in order to fine tune the molecular properties and improve device performance. In this context, the tetrathiafulvalene (TTF)- and 1,5-dioxynaphthanlene (DNP)-containing rotaxanes and catenanes have been the most studied to date. These bistable compounds contain, however, undesirable elements of complexity that arises from the two possible substitution patterns at the TTF unit (cis and trans isomers), in addition to the inherent flexibility of the backbone of the system. A great disadvantage of the flexible nature of the [2]rotaxanes is that this design renders it very difficult, if not impossible, to harvest the mechanical energy in the movement of the ring along the axis of the dumbbell. The flexibility of the [2]rotaxanes also leads to various conformations in solution, as well as in more defined medias, thereby complicating the analysis of obtained results. It was therefore decided to undertake the task of eliminating the factors that lead to the above mentioned complications by use of monopyrrolotetrathiafulvalene (MPTTF) and by rigidifying the backbone of the TTF- and DNP-containing [2]rotaxanes. For this purpose, two [2]rotaxanes were synthesized (Box), the first being a two-station (MPTTF and DNP) [2]rotaxane which exists predominantly as a single translational isomer (14+) and the second being a degenerate DNP shuttle (24+), which is suitable for measuring the shuttling rates in such [2]rotaxanes. The synthesis, characterization (NMR and UV-vis spectroscopies) and electrochemical/chemical switching of the rotaxanes will be discussed during the presentation.
|
|
Materials, Devices, and Switches
8:00 AM-12:00 PM, Sunday, 10 September 2006 Moscone Center -- Room 132, Oral
Division of Organic Chemistry |
