title: Synthesis and characterization of stable hypervalent carbon compounds (10-C-5) bearing a 2,6-bis(p-substituted phenyloxymethyl)benzene ligand.
abstract: X-ray analysis of bis(p-fluorophenyl)methyl cation bearing a 2,6-bis(p-tolyloxymethyl)benzene ligand showed a symmetrical structure (10-C-5) where the two C-O distances are identical, although the distance (2.690(4) A) is longer than those (2.43(1) and 2.45(1) A) of 1,8-dimethoxy-9-dimethoxymethylanthracene monocation, which was recently reported by us. However, X-ray analysis of the more stable aromatic xanthylium cation with the same benzene ligand showed the tetracoordinate carbon structure where only one of the two oxygen ligands is coordinated with the central carbon atom. These results clearly indicate that the carbocations (10-C-5) bearing the sterically flexible benzene ligand were quite sensitive to the electronic effect on the central carbon atom. The electron distribution analysis by accurate X-ray measurements and the density functional calculation on the initially mentioned bis(p-fluorophenyl)methyl cation clearly show that the central carbon atom and the two oxygen atoms are bonded even if the bond is weak and ionic based on the small value of the electron density (rho(r)) and the small positive Laplacian value (nabla(2)rho(r)) at the bond critical points.
authors.affiliation: Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors.forename: Kin-Ya
authors.initials: KY
authors.lastname: Akiba
authors.forename: Yuji
authors.initials: Y
authors.lastname: Moriyama
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Mizozoe
authors.forename: Hideki
authors.initials: H
authors.lastname: Inohara
authors.forename: Takako
authors.initials: T
authors.lastname: Nishii
authors.forename: Yohsuke
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Mao
authors.initials: M
authors.lastname: Minoura
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hashizume
authors.forename: Fujiko
authors.initials: F
authors.lastname: Iwasaki
authors.forename: Nozomi
authors.initials: N
authors.lastname: Takagi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ishimura
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nagase