American Chemical Society
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Orthogonal Recognition Processes Drive the Assembly and Replication of a [2]Rotaxane

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posted on 2015-12-30, 00:00 authored by Tamara Kosikova, Nurul Izzaty Hassan, David B. Cordes, Alexandra M. Z. Slawin, Douglas Philp
Within a small, interconnected reaction network, orthogonal recognition processes drive the assembly and replication of a [2]­rotaxane. Rotaxane formation is governed by a central, hydrogen-bonding-mediated binding equilibrium between a macrocycle and a linear component, which associate to give a reactive pseudo­rotaxane. Both the pseudo­rotaxane and the linear component undergo irreversible, recognition-mediated 1,3-dipolar cycloaddition reactions with a stoppering maleimide group, forming rotaxane and thread, respectively. As a result of these orthogonal recognition-mediated processes, the rotaxane and thread can act as auto-catalytic templates for their own formation and also operate as cross-catalytic templates for each other. However, the interplay between the recognition and reaction processes in this reaction network results in the formation of undesirable pseudo­rotaxane complexes, causing thread formation to exceed rotaxane formation in the current experimental system. Nevertheless, in the absence of competitive macrocycle-binding sites, realization of a replicating network favoring formation of rotaxane is possible.