title: Hetero-double-helix formation by an ethynylhelicene oligomer possessing perfluorooctyl side chains.
abstract: Monomeric to pentameric (P)-ethynylhelicene oligomers possessing perfluorooctyl side chains were synthesized. The circular dichroism (CD) and vapor pressure osomometry (VPO) studies indicated the formation of a helix-dimer for the (P)-pentamer, for example, in trifluoromethylbenzene at 5 degrees C at concentrations above 2 x 10(-6) M. Compared with a (P)-pentamer possessing decyloxycarbonyl side chains, the perfluorooctyl (P)-pentamer exhibited lower solubilities in organic solvents, formed a thermodynamically more stable helix-dimer, and exhibited a mirror image CD spectrum. The perfluorooctyl (P)-pentamer formed a hetero-helix dimer with a decyloxycarbonyl (M)-pentamer but not with a (P)-pentamer. It indicated higher stability of the hetero-helix dimer over the homo-helix dimers.
authors: Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan.
authors: Ryo
authors: R
authors: Amemiya
authors: Nozomi
authors: N
authors: Saito
authors: Masahiko
authors: M
authors: Yamaguchi
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D002942:Circular Dichroism; D005466:Fluorocarbons / Q000737:chemistry*; D006860:Hydrogen Bonding; D015394:Molecular Structure; D009995:Osmosis; D011083:Polycyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011312:Pressure; D012995:Solubility; D013816:Thermodynamics; D014835:Volatilization
chemical_list: D005466:Fluorocarbons; D011083:Polycyclic Compounds; C031660:helicenes; D000114:Acetylene