ORGN 795 |
| The continued development of electrochemically switchable bistable rotaxanes incorporating cyclobis(paraquat-p-phenylene) (CBPQT4+) for applications as molecular actuators1 and in molecular electronics will be greatly facilitated by improved synthetic methods. Due to the sensitivity of the CBPQT4+ ring to many bases and nucleophiles, rotaxanes have traditionally been obtained by clipping a partially formed ring around a dumbbell-shaped molecule containing an appropriate CBPQT4+ recognition site. Though this approach has been successfully used in the preparation of many mechanically interlocked systems, it is often low-yielding — a particularly unfortunate feature in the late stages of synthesis that limits the scope of this approach to [2] (and rarely [3]) rotaxanes. On account of its excellent functional group compatibility and mild reaction conditions, we hypothesized that the Cu(I)-catalyzed 1,3-cycloaddition of organic azides and alkynes might be utilized to efficiently stopper CBPQT4+ pseudorotaxanes (Scheme). This alternative methodology complements the clipping approach described above, and allows the preparation of [2]rotaxanes in excellent yield. The efficient synthesis of CBPQT4+ containing [2], [3], and [4]rotaxanes will be described, as well as details of how to integrate these molecules into Si nanowire molecular electronic devices.
|
|
Total Synthesis, Materials, Molecular Recognition, Process R&D, and Physical Organic Chemistry
8:00 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster
Sci-Mix
Division of Organic Chemistry |
