Synthesis of the Phenoxonium Cation of an α-Tocopherol Model Compound Crystallized with Non-Nucleophilic [B(C₆F₅)₄]^- and (CB₁₁H₆Br₆)^- Anions

Abstract

The phenoxonium cation of a vitamin E model compound has been crystallized using the non-nucleophilic carborane and tetrakis(pentafluorophenyl)borate counteranions. The crystal structures confirm the assignment of the unusually stable phenoxonium cation and indicate that there is a substantial shortening of the carbon-oxygen bond lengths of the para-carbon atoms in the phenolic ring and a substantial increase of the carbon-oxygen bond length at the quaternary carbon. The crystallographic data are in excellent agreement with structural predictions from molecular orbital calculations.

Carbocations

“…Phenoxonium cation (59), a vitamin E model, was obtained by treatment of the phenol precursor with NO + SbF 6 − in acetonitrile. 127 The crystal structure of the SbF 6 − salt showed bond lengths consistent with structure (60) as the major resonance contributor, with structure (59) of relatively minor importance (as also concluded in ref. 126).…”

Hydroquinone Electrochemistry on Carbon Nanotubes is Accelerated by Nanographite Impurities

“…[14] Hydroquinone and its derivatives are highly important biologically active compounds. [15][16][17][18] They play a role in many biological processes and have been used as mediators in a variety of biosensory systems. [15][16][17][18][19] There have been several reports on the "electrocatalytic" determination of hydroquinone on carbon nanotubes.…”

Bioinspired Porous Hybrid Materials via Layer‐by‐Layer Assembly

“…Recent progress in AAO templating synthesis includes the preparation of nanotest-tubes [123][124][125]. Unlike the nanotubes that are open at both ends (resembling pipes), silica nano-test-tubes are prepared through a simple modification of the template-synthesis method [123].…”

“…Unlike the nanotubes that are open at both ends (resembling pipes), silica nano-test-tubes are prepared through a simple modification of the template-synthesis method [123]. The nano-test-tubes are able to be corked with polystyrene latex nanoparticles [124] or gold nanoparticles [125] through chemical self-assembly. A potential application for these novel nanotubes is as vehicles for the delivery of drugs, DNA, proteins or other biomolecules.…”

“…A potential application for these novel nanotubes is as vehicles for the delivery of drugs, DNA, proteins or other biomolecules. This test-tube geometry would allow for convenient filling of the nanotube with the biomolecule of interest and, by applying a cap to the open end, the biomolecule could be kept bottled-up inside until it is ready to be delivered [124,125].…”