WCC 2 |
| Wurster's crowns are a new class of redox-active macrocycles that are distinguished by the presence of an ortho-, meta- or para-phenylenediamine subunit within the macrocyclic framework. The para-phenylenediamine-containing isomers, unlike the ortho- and meta-phenylenediamine-containing isomers, have reversible electrochemistry but oxidize at potentials too low to allow for the encapsulation of cationic guests having even modest oxidizing ability. Herein, we describe the synthesis and properties of a series of new functionalized para-Wurster's crown ethers whose oxidation potentials span a wide electrochemical window (nearly 1 V!). By modulating the functionality of the phenylenediamine moiety through electronic and steric means, the oxidation potentials of the resulting macrocycles differ with respect to that of the parent para-Wurster's crowns. The results from these crown ether prototypes can be applied to other macrocyclic frameworks that are conducive to the encapsulation of guests of varying oxidizing abilities such as the transition and heavy metal ions. |
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Many Faces of Chemistry: The Merck Index Women in Chemistry Award Symposium
9:15 AM-11:50 AM, Monday, August 20, 2007 Westin Boston Waterfront -- Revere, Oral
Women Chemists Committee |