Friday, 6 October 2006
South Ballroom (Binghamton Regency Hotel and Conference Center)
376

Preparation and deprotection of nosyl-protected aza-crown-ether macrocycles, an ion encapsulation study of protected vs. free macrocyclic amines

Timothy Garrett and Marc Harris. Lebanon Valley College, Annville, PA

Alkali metal ion complexation by classic crown ether and aza-crown host molecules has been well documented in the literature. These systems display excellent selectivity for various ions based on steric requirements and hard-soft interactions. Recently, functionalized versions of these macrocycles have been reported that either display enhanced ion-binding, improved selectivity, or an external response to report successful binding. To this end, a series of bipyridine containing aza-crown-ether macrocycles were synthesized by reacting a dibromo-substitued bipyridine unit with a pre-organized N-nosyl protected polyamine. Once deprotected, these aza-crown analogues are expected to display similar ion selectivity and binding strength based on the size and number of donor atoms created by the bipyridine-ether pockets. In addition, by metallating the outwardly directed bipyridine units with photoactive transition metal centers these complexes may function as chemosensory devices that visibly display the encapsulation of small cationic molecules and ions. This photoactive behavior results from the intermolecular facial interaction of two or more coordinated d-8 square planar metal centers. This paper reports the conditions required for nosyl group deprotection and the initial ion extraction studies of the protected macrocycles.

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