Synthesis and Characterization of Stable Hypervalent Carbon Compounds (10-C-5) Bearing a 2,6-Bis(p-substituted phenyloxymethyl)benzene Ligand

• Published in: Journal of the American Chemical Society Vol. 127; no. 16; pp. 5893 - 5901
• Main Authors: Akiba, Kin-ya, Moriyama, Yuji, Mizozoe, Mitsuhiro, Inohara, Hideki, Nishii, Takako, Yamamoto, Yohsuke, Minoura, Mao, Hashizume, Daisuke, Iwasaki, Fujiko, Takagi, Nozomi, Ishimura, Kazuya, Nagase, Shigeru
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 27.04.2005; Amer Chemical Soc
• Subjects: Aliphatic, non-condensed and condensed benzenic, and alicyclic compounds; Chemistry; Chemistry, Multidisciplinary; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Noncondensed benzenic compounds; Organic chemistry; Organic compounds; Physical Sciences; Physics; Preparations and properties; Science & Technology; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; ACCURATE; TRIDENTATE ANTHRACENE LIGAND; COMPLEXES; PLATINUM; IONS; MULTIPLE NEIGHBORING GROUPS; 1,8-POSITIONS; Organic synthesis; Electronic structure; Organic cation; Molecular structure; Chemical stability; Electron charge distribution; NMR spectrometry; X ray diffraction; Crystalline structure
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja043802t

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) Å) is longer than those (2.43(1) and 2.45(1) Å) 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 (ρ(r)) and the small positive Laplacian value (∇2ρ(r)) at the bond critical points.