title: Synthesis and complexing properties of [2.n](2,6)pyridinocrownophanes.
abstract: [2.n](2,6)Pyridinocrownophanes (3a-e) were efficiently prepared by intramolecular [2 + 2] photocycloaddition of vinylpyridine derivatives under irradiation using a 400-W high-pressure mercury lamp through a Pyrex filter. They were of cis-configuration with respect to the cyclobutane ring, which was proven by the specific methine proton NMR resonances at delta 3.98-4.08. From ESI-MS analysis 3a-e were found to form 1:1 complexes with Ag+ cation. In a liquid-liquid extraction, 3 showed the highest affinity toward Ag+ cation among several heavy metal nitrates. In this series, 3c possessing four ethereal oxygen atoms was found to show the highest Ag+ affinity, according to the liquid-liquid extraction and determination of stability constant with the cation. The photoreactivity of precursor vinylpyridines is discussed by the predictor gamma(r(c)) proposed by Caldwell.
authors.affiliation: Department of Nano-Material Systems, Graduate School of Engineering, and Department of Chemistry, Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu 376-8515, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Inokuma
authors.forename: Hayato
authors.initials: H
authors.lastname: Ide
authors.forename: Tomomi
authors.initials: T
authors.lastname: Yonekura
authors.forename: Takashi
authors.initials: T
authors.lastname: Funaki
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Kondo
authors.forename: Satoru
authors.initials: S
authors.lastname: Shiobara
authors.forename: Toshitada
authors.initials: T
authors.lastname: Yoshihara
authors.forename: Seiji
authors.initials: S
authors.lastname: Tobita
authors.forename: Jun
authors.initials: J
authors.lastname: Nishimura
mesh_terms: D043844:Crown Ethers / Q000138:chemical synthesis* / Q000737:chemistry* / Q000528:radiation effects; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry; D010777:Photochemistry; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014753:Vinyl Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects
chemical_list: D043844:Crown Ethers; D011725:Pyridines; D014753:Vinyl Compounds; D009532:Nickel