Exploring anion-induced conformational flexibility and molecular switching in a series of heteroaryl-urea receptorsElectronic supplementary information (ESI) available. CCDC 970878 and 970877. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4sc00950a

• Main Authors: Gavette, Jesse V, Evoniuk, Christopher J, Zakharov, Lev N, Carnes, Matthew E, Haley, Michael M, Johnson, Darren W
• Format: Journal Article
• Language: English
• Published: 03.06.2014
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c4sc00950a

Anion binding studies of 1,10-phenanthroline- and 2-pyridyl-substituted urea-based receptors reveal that guest-dependent conformations exist in structural variants related to a previously investigated bipyridyl-based receptor. Dynamic conformational switching persists in a monofunctional pyridyl-urea receptor, and the preorganization provided by a phenanthroline-based analogue promotes convergence of anion coordinating groups to a single guest. Despite this predisposition for anion coordination, the conformational flexibility of the bipyridyl-based receptor provides the most selective motif for H 2 PO 4 − coordination. Furthermore, the two new phenanthrolyl- and pyridyl-receptors serve as models of the bipyridyl-based receptor, elucidating accurate stepwise association constants for 1 : 2 host/guest binding by this receptor, and suggest that oxoanions prefer the embrace of a " U " conformation in 1 : 1 complexes. Anion-induced conformational switching provides insight into binding selectivity in a series of heteroaryl-urea receptors.