title: Reversible adaptation to photoinduced shape switching by oligomer-macrocycle interconversion with component selection in a three-state constitutional dynamic system.
abstract: Light irradiation of the molecular photoswitch 1-E causes isomerization into the 1-Z configuration stabilized by an internal hydrogen bond. 1-E bears aldehyde groups allowing for dynamic covalent reaction with linear diamines. On photoinduced E/Z shape switching of 1 in presence of diamines, the system undergoes interconversion between two states, a non-cyclic oligomeric one and a macrocyclic one, corresponding respectively to the E and Z configurations of 1. With a mixture of linear α,ω-diamines, 1-E yields non-selective dynamic oligomers by random incorporation of diamine components. Photoswitching to the 1-Z form leads to constitutional adaptation with preferential formation of the macrocycle incorporating the best suited diamine, H2 N(CH2 )7 NH2 . In presence of metal cations, the E form switches from its unbound W shape to its coordinated U shape and yields the macrocycle resulting from the selective incorporation of the diamine H2 NCH2 CH2 OCH2 CH2 NH2 that contains an additional O coordination site. Taken together, the results obtained describe constitutional adaptation in a triple state system: an oligomeric one and two different macrocyclic ones generated in response to two orthogonal agents, a physical stimulus, light, or a chemical effector, metal cations. These three states present, towards the incorporation of diamine components, respectively no selection, photoselection and metalloselection.
authors.affiliation: Laboratoire de Chimie Supramoléculaire, ISIS, Université de Strasbourg, 8 Allée Gaspard Monge, 67000 Strasbourg (France).
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Vantomme
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Lehn
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D003959:Diamines / Q000737:chemistry*; D006860:Hydrogen Bonding; D007536:Isomerism; D008027:Light; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008968:Molecular Conformation; D055668:Photochemical Processes
chemical_list: D000447:Aldehydes; D003959:Diamines; D047028:Macrocyclic Compounds; D008670:Metals
keywords: adaptative chemistry; constitutional dynamics; metalloselection; photoselection; switching