title: Mono- and ditopic models of binding of a photochromic chromene annelated with an 18-crown-6 ether with protonated amino acids.
abstract: In this work, the interaction of protonated amino acids with a chromene bearing a fused 18-crown-6 ether moiety was studied by UV-vis and NMR spectroscopy. Initial closed forms of the chromene form monotopic 1 : 1 complexes, the ammonium group being localized inside the crown ether cavity. UV-irradiation leads to transformation of the ring-closed species into the ring-opened form. Depending on the amino acid length, either ditopic or monotopic 1 : 1 complexes are formed. Such complexes are stabilized by the additional H-bonding between the carboxylic group of the acid and the carbonyl oxygen atom of the ring-opened form. Cessation of the irradiation results in ring-closure to the chromene with concomitant change of the complexation mode.
authors.affiliation: A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova st., 28, 119991 Moscow, Russia. paramonov@ineos.ac.ru
authors.forename: Sergey
authors.initials: S
authors.lastname: Paramonov
authors.forename: Yury
authors.initials: Y
authors.lastname: Fedorov
authors.forename: Vladimir
authors.initials: V
authors.lastname: Lokshin
authors.forename: Elena
authors.initials: E
authors.lastname: Tulyakova
authors.forename: Gaston
authors.initials: G
authors.lastname: Vermeersch
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Delbaere
authors.forename: Olga
authors.initials: O
authors.lastname: Fedorova
mesh_terms: D000042:Absorption; D000596:Amino Acids / Q000737:chemistry*; D001578:Benzopyrans / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry*; D008956:Models, Chemical; D055668:Photochemical Processes; D011522:Protons
chemical_list: D000596:Amino Acids; D001578:Benzopyrans; D043844:Crown Ethers; D011522:Protons