title: Switching properties of a spiropyran-cucurbit[7]uril supramolecular assembly: usefulness of the anchor approach.
abstract: A nitrospiropyran, which was modified with a cadaverine-derived anchor, was investigated with respect to its thermally induced isomerizations, hydrolytic stability of the merocyanine form, and photochromic ring closure. The host-guest complexation of the anchor by the cucurbit[7]uril macrocycle, evidenced by absorption titration, NMR spectroscopy, and electrospray ionization mass spectrometry, produced significant improvements of the switching properties of the photochrome: 1) appearance of the merocyanine form about 70 times faster, 2) practically unlimited hydrolytic stability of the merocyanine (two and a half days without any measureable decay), and 3) fast, clean, and fatigue-resistant photoinduced ring closure back to the spiro form. The importance of an adequate molecular design of the anchor was demonstrated by including control experiments with spiropyrans with a shorter linker or without such structural asset.
authors.affiliation: Department of Chemical and Biological Engineering, Physical Chemistry, Chalmers University of Technology, Göteborg, Sweden.
authors.forename: Jesper R
authors.initials: JR
authors.lastname: Nilsson
authors.forename: Cátia
authors.initials: C
authors.lastname: Parente Carvalho
authors.forename: Shiming
authors.initials: S
authors.lastname: Li
authors.forename: José Paulo
authors.initials: JP
authors.lastname: Da Silva
authors.forename: Joakim
authors.initials: J
authors.lastname: Andréasson
authors.forename: Uwe
authors.initials: U
authors.lastname: Pischel
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D001952:Bridged-Ring Compounds / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D006868:Hydrolysis; D007093:Imidazoles / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D007536:Isomerism; D008027:Light; D009574:Nitro Compounds / Q000737:chemistry*; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D001578:Benzopyrans; D001952:Bridged-Ring Compounds; D004396:Coloring Agents; D007093:Imidazoles; D007211:Indoles; D009574:Nitro Compounds; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils; C548873:merocyanine; C088184:spiropyran