title: Selective product amplification of thymine photodimer by recognition-directed supramolecular assistance.
abstract: Two symmetric ditopic supramolecular templates (1 and 2) each presenting two hydrogen bonding recognition subunits were synthesized. Each such subunit comprises the same donor and acceptor pattern, capable of binding a substrate molecule with complementary hydrogen bonding groups to form a supramolecular complex. Substrate molecules, such as thymine or uracil derivatives, yield 2 : 1 complexes with the acceptors involving two hydrogen bonds to each subunit with ideal orientation for subsequent [2 + 2] dimerization upon photoirradiation. Selective syn photoproduct formation and concomitant suppression of the trans isomer are favored by orientation of the two guest nucleobases within the template cleft. Complementary donor and acceptor hydrogen bonding induced positioning of the two substrates and steric hindrance within the template clefts are responsible for the selective product formation.
authors.affiliation: Laboratoire de Chimie Supramoléculaire, ISIS-Université Louis Pasteur, 8, allée Gaspard Monge, BP 70028, 67083, Strasbourg cedex, France.
authors.forename: W G
authors.initials: WG
authors.lastname: Skene
authors.forename: Volker
authors.initials: V
authors.lastname: Berl
authors.forename: Hélène
authors.initials: H
authors.lastname: Risler
authors.forename: Richard
authors.initials: R
authors.lastname: Khoury
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Lehn
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D019281:Dimerization; D006860:Hydrogen Bonding; D007700:Kinetics; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D013941:Thymine / Q000737:chemistry*; D014498:Uracil / Q000737:chemistry
chemical_list: D014498:Uracil; D013941:Thymine