title: Supramolecular Dimerization and [2 + 2] Photocycloaddition Reactions of Crown Ether Styryl Dyes Containing a Tethered Ammonium Group: Structure-Property Relationships.
abstract: Molecular self-assembly is an effective strategy for controlling the [2 + 2] photocycloaddition reaction of olefins. The geometrical properties of supramolecular assemblies are proven to have a critical effect on the efficiency and selectivity of this photoreaction both in the solid state and in solution, but the role of other factors remains poorly understood. Convenient supramolecular systems to study the structure-property relationships are pseudocyclic dimers spontaneously formed by styryl dyes containing a crown ether moiety and a remote ammonium group. New dyes of this type were synthesized to investigate the effects of structural and electronic factors on the quantitative characteristics of supramolecular dimerization and [2 + 2] photocycloaddition in solution. Variable structural parameters for the styryl dyes were the size and structure of macrocyclic moiety, the nature of heteroaromatic residue, and the length of the ammonioalkyl group attached to this residue. Quantum chemical calculations of the pseudocyclic dimers were performed in order to interpret the relationships between the structure of the ammonium dyes and the efficiency of the supramolecular photoreaction. One of the dimeric complexes was obtained in the crystalline state and studied by X-ray diffraction. The results obtained demonstrate that the photocycloaddition in the pseudocyclic dimers can be dramatically affected by the electronic structure of the styryl moieties, as dependent on the electron-donating ability of the substituents on the benzene ring, and by the conformational flexibility of the pseudocycle, which determines the mobility of the olefinic bonds. The significance of electronic factors is highlighted by the fact that the photocycloaddition quantum yield in geometrically similar dimeric structures varies from ≤10(-4) to 0.38. The latter value is unusually high for olefins in solution.
authors.affiliation: Institute of Problems of Chemical Physics, Russian Academy of Sciences , Chernogolovka 142432, Moscow Region, Russian Federation.|Photochemistry Center, Russian Academy of Sciences , ul. Novatorov 7A-1, Moscow 119421, Russian Federation.
authors.forename: Evgeny N
authors.initials: EN
authors.lastname: Ushakov
authors.affiliation: Photochemistry Center, Russian Academy of Sciences , ul. Novatorov 7A-1, Moscow 119421, Russian Federation.
authors.forename: Artem I
authors.initials: AI
authors.lastname: Vedernikov
authors.affiliation: Photochemistry Center, Russian Academy of Sciences , ul. Novatorov 7A-1, Moscow 119421, Russian Federation.
authors.forename: Natalia A
authors.initials: NA
authors.lastname: Lobova
authors.affiliation: Photochemistry Center, Russian Academy of Sciences , ul. Novatorov 7A-1, Moscow 119421, Russian Federation.
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Dmitrieva
authors.affiliation: N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences , Leninskiy prosp. 31, Moscow 119991, Russian Federation.
authors.forename: Lyudmila G
authors.initials: LG
authors.lastname: Kuz'mina
authors.affiliation: Department of Chemistry, M. V. Lomonosov Moscow State University , Leninskie Gory 1, Moscow 119991, Russian Federation.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Moiseeva
authors.affiliation: Department of Chemistry, Durham University , South Road, Durham DH1 3LE, United Kingdom.
authors.forename: Judith A K
authors.initials: JA
authors.lastname: Howard
authors.affiliation: Photochemistry Center, Russian Academy of Sciences , ul. Novatorov 7A-1, Moscow 119421, Russian Federation.
authors.forename: Michael V
authors.initials: MV
authors.lastname: Alfimov
authors.affiliation: Photochemistry Center, Russian Academy of Sciences , ul. Novatorov 7A-1, Moscow 119421, Russian Federation.|Department of Chemistry, M. V. Lomonosov Moscow State University , Leninskie Gory 1, Moscow 119991, Russian Federation.
authors.forename: Sergey P
authors.initials: SP
authors.lastname: Gromov
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry*; D004396:Coloring Agents / Q000138:chemical synthesis / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry*; D003500:Cyclization; D061565:Cycloaddition Reaction; D019281:Dimerization; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D055668:Photochemical Processes; D013329:Structure-Activity Relationship; D013343:Styrenes / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D004396:Coloring Agents; D043844:Crown Ethers; D046911:Macromolecular Substances; D013343:Styrenes