title: Exploring Anion-Induced Conformational Flexibility and Molecular Switching in a Series of Heteroaryl-Urea Receptors.
abstract: 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 H2PO4-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.
authors: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon, Eugene, OR, 97403-1253, USA.
authors: Jesse V
authors: JV
authors: Gavette
authors: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon, Eugene, OR, 97403-1253, USA.
authors: Christopher J
authors: CJ
authors: Evoniuk
authors: CAMCOR-Center for Advanced Materials Characterization in Oregon, University of Oregon, Eugene, OR, 97403, USA.
authors: Lev N
authors: LN
authors: Zakharov
authors: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon, Eugene, OR, 97403-1253, USA.
authors: Matthew E
authors: ME
authors: Carnes
authors: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon, Eugene, OR, 97403-1253, USA.
authors: Michael M
authors: MM
authors: Haley
authors: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon, Eugene, OR, 97403-1253, USA.
authors: Darren W
authors: DW
authors: Johnson