title: Effects of alkyl chain length, solvent and tandem Claisen rearrangement on two-dimensional structures of noncyclic isobutenyl compounds: scanning tunnelling microscopic study.
abstract: A series of isobutenyl compounds possessing various alkyl chain lengths (C(n)-1) with a carbon number of n = 14-21 were synthesized and their two-dimensional (2D) structures were systematically studied using scanning tunnelling microscopy (STM) at a highly oriented pyrolytic graphite (HOPG)/solvent interface. Two kinds of solvent, such as 1-phenyloctane (PO) and 1-phenylnonane (PN), were selected to examine the 2D structures by changing the alkyl chain length of the isobutenyl compounds. At the HOPG/PO interface, C(n)-1 molecules with shorter alkyl chains (n = 14-17) showed the same zig-zag shaped 2D structure regardless of the alkyl chain length, whereas an odd-even effect was recognized in C(n)-1 compounds with longer alkyl chains (n = 18-21) displaying the wavy and tripod structures, alternately. This odd-even effect was also observed at the HOPG/PN interface rather more distinctly. These results suggest that there is a specific alkyl chain length range that shows the odd-even effect in the present 2D system. After a tandem Claisen rearrangement (TCR), the 2D structures of all the C(n)-2 compounds formed were converged into the same linear structure, i.e. the odd-even effect was cancelled by the conformational limitation induced by the TCR.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan. y.kikkawa@aist.go.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kikkawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Omori
authors.forename: Mayuko
authors.initials: M
authors.lastname: Takahashi
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kanesato
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Hiratani
mesh_terms: D000475:Alkenes / Q000138:chemical synthesis / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D015394:Molecular Structure; D012997:Solvents / Q000737:chemistry
chemical_list: D000475:Alkenes; D012997:Solvents; C008176:isobutylene