title: Engineering Light-Mediated Bistable Azobenzene Switches Bearing Urea d-Aminoglucose Units for Chiral Discrimination of Carboxylates.
abstract: The symmetrical molecular receptors 1a and 1b consisting of a photochemically addressable azobenzene tether functionalized with urea hydrogen-bonding groups and d-carbohydrates as chiral selectors were developed to achieve control over the chiral recognition of α-amino acid-derived carboxylates. The photo- and thermally interconvertible planar E-1 and concaved Z-1 were found to exhibit different affinities, selectivities, and binding modes toward these biologically important anions in a highly polar medium (DMSO + 0.5% H2O). Binding affinity for the same enantiomerically pure guest was up to 3 times higher for E-1 than for Z-1 (cf. parameter β). In addition, the rate of thermal Z → E isomerization was found to depend on the chiral binding ability of Z-1, i.e., more strongly bound carboxylate enantiomer as well as higher enantiomer concentration caused faster relaxation to E-1.
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Kajetan
authors.initials: K
authors.lastname: Dąbrowa
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Patryk
authors.initials: P
authors.lastname: Niedbała
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Jurczak