Facile Synthesis, Crystal Structure, and Oxidizability of a Novel Benzene Tris-Annelated with Bicyclo[2.2.2]oct-2-ene

Abstract

Trimerization of 2,3-dibromobicyclo[2.2.2]oct-2-ene by the use of butyllithium followed by subsequent cyclization gives 1,2:3,4:5,6-tris(bicyclo[2.2.2]oct-2-eno)benzene (3), the highly symmetrical structure of which is established by X-ray crystallography. Compound 3 is reversibly oxidized upon cyclic voltammetry at 1.25 V vs Ag/Ag+ in CH3CN.

Fabrication of Conducting Thin Films on the Surfaces of 7,7,8,8-Tetracyanoquinodimethane Single-Component and Charge-Transfer Complex Single Crystals: Nucleation, Crystal Growth, Morphology, and Charge Transport

“…The donor strength is usually evaluated from the redox potential for the first oxidation process ( E 1/2 ox ) in the solution, and the E 1/2 ox values are summarized in Table . − The strength of the CT interaction in the complex crystal can be approximated from the difference between E 1/2 ox of the donor and the redox potential for the first reduction process of the acceptor ( E 1/2 red ), namely, Δ E redox = E 1/2 ox – E 1/2 red , and it has been proposed by Torrance that a linear correlation of h ν CT = Δ E redox + C ( h ν CT , energy of the CT band; C , constant) can be assumed for the complexes with neutral ground states . In our study, since the acceptor is always TCNQ, one can expect that a linear correlation of h ν CT = E 1/2 ox + C ′ ( C ′: constant) will appear.…”

Professor Tetsuo Nozoe and My Tropylium Ion Chemistry

“…When we treated this with two equivalents of butyllithium or sodium naphthalenide at room temperature, it smoothly gave tris‐BCO‐fused benzene ( 20 ) in 80 or 89% yield, respectively, as a single product, most probably via one‐electron transfer and reductive cyclization (Scheme ) . The highly symmetric structure with nearly D 3 h symmetry of benzene 20 was demonstrated by X‐ray crystallography (Figure ) . The bond‐length alternation is very small, the aromatic bond within the bicyclic system being elongated by only 0.015 Å on average.…”

“…The steric and electronic effects of the rigid σ frameworks surrounding the central π system are reflected in its ease of one‐electron oxidation and the stabilization of the formed radical cation. The cyclic voltammetry (CV) conducted for 20 and hexamethylbenzene (HMB) in acetonitrile gave the voltammograms shown in Figure . In contrast to HMB, which exhibited an irreversible oxidation peak at E pa 1.38 V vs. Ag/Ag + , benzene 20 showed a well‐defined reversible oxidation wave at E 1/2 1.25 V ( E pa 1.29 V).…”

“… Cyclic voltammograms of 20 and hexamethylbenzene ( HMB ) in acetonitrile (1 × 10 −3 M); scan rate, 0.1 V s −1 ; supporting electrolyte, Bu 4 N + ClO 4 − …”

Studies on Two- and Three-Dimensional π-Conjugated Systems with Unique Structures and Properties

“…Among possible polycycloalkenes to be annelated to the cyclic -systems, we first selected bicyclo-[2.2.2]octene (abbreviated as BCO throughout this article), because it does not impose much angle strain on the -system and furnishes -bonds rigidly fixed at the right position for -interaction. As the most basic cyclic -conjugated systems, benzene 1, 10 naphthalene 2, 11 anthracene 3, 12 and fluorene 4 13 were synthesized. Also, benzyne 5 annelated with two BCO groups was generated in solution.…”