AEI 81 |
| The means, by which mechanically interlocked molecules, such as catenanes, rotaxanes, and knots, have been made, has undergone a major transformation during the past two decades. Recently, new approaches have been pursued by us and other groups, which proceed under conditions compatible with the functional groups and host-guest binding present in these mechanically interlocked molecules. One of these approaches involves the use of Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition – namely, click reaction, in the formation of catenanes and rotaxanes. This synthetic strategy is promising as it opens up the pathway to various interlocked structures that have not been accessible earlier in high yields, as a result of synthetic limitations associated with the previously used "clipping" reactions. Using the 'click reaction' mediated 'threading-followed-by-stoppering' strategy various bistable [n]rotaxanes (Box) have been synthesized recently.1 Architectures of these type include (i) a bistable [2]rotaxane1a (A) which was used to study the effect of the 1,2,3-triazole ring, introduced into the rotaxane as a result of the cycloaddition reaction between an azide and an alkyne, on the kinetics and thermodynamics of the switching process, (ii) a novel bistable [4]rotaxane (B) which was not accessible earlier, (iii) a liquid-crystalline bistable [2]rotaxane1b (C) which shows a Smectic A phase over a large range of temperatures, and (iv) an exotic mechanically interlocked compound dubbed the "molecular carousel" (D). 1.a) Aprahamian, I.; Dichtel, W. R.; Ikeda, T.; Heath, J. R.; Fraser, J. F. Org. Lett. 2007, 9, 1287–1290. b) Aprahamian, I.; Yasuda, T.; Ikeda, T.; Saha, S.; Dichtel, W. R.; Isoda, K.; Kato, T.; Stoddart J. F. Angew. Chem. Int. Ed. 2007, 46, In Press.
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Academic Employment Initiative
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Sci-Mix
Academic Employment Initiative |
