Kinetics and mechanism of hydride transfer from a dicarbazolylmethane to triphenylmethyl cation: stable cations from carbazole derivatives

Abstract

Hydride ion transfer between Ph,C+SbCI,and bis-(9-ethyl-3-carbazolyI)methane leads to a blue di-(carbazoly1)methyl dye. Kinetic studies show that the reaction rates are inversely proportional to solvent dielectric in accordance with the general theory of solvent effects on organic reactions. Characterization of the blue dye permits rationalization of many previous reports relating to coloured intermediates from acid-catalysed reactions of carbazole derivatives.

Heteroaromatic Belts through Fold‐in Synthesis: Mechanistic Insights into a Macrocycle‐Templated Friedel–Crafts Alkylation

“…The NMR data are consistent with the formulation of 1B n as a cyclophane-based [32] oligomer, in which 1B units are linked through the 3' positions, to form a methylene-carbazole [33][34][35] backbone (Scheme 2). The presence of a stereogenic plane in the 1B unit leads to stereoisomerism in the 1B n chain, and the two diastereomers of 1B 2 can serve as models of the respective racemo and meso dyads in 1B n .…”

“…The resolution of the NMR spectra of 1B n is insufficient to detect small contributions of 6‐substitution; however, the dominance of 3′‐alkylation is indicated by specific spectral features, including (a) the significant intensity of the 6‐H peak (6.5 ppm), (b) the s1′‐C shift in 1B n (109.7–110.7 ppm) corresponding with s1′‐C in 1B 2 (110.2 ppm) rather than with u1′‐C (109.0 ppm), and (c) the close similarity between 13 C shifts of the remaining carbazole positions observed in the HSQC spectra of 1B 2 and 1B n . Freshly prepared 1B n displays a characteristic blue color in solution ( λ max ≈630 nm), which, in analogy to simple methylene‐carbazole polymers,34, 35 can be attributed to a small contribution of oxidized s3′α bridges (Scheme ). Because of their carbocationic character, such oxidized bridges can undergo further condensation, leading to oligomer branching,35 though in the case of 1B n , the process may be hindered sterically.…”

“…Freshly prepared 1B n displays a characteristic blue color in solution (l max % 630 nm), which, in analogy to simple methylene-carbazole polymers, [34,35] can be attributed to a small contribution of oxidized s3'a bridges (Scheme 2). Positions 6 on the bridged dicarbazole fragment of 1B are potentially susceptible to electrophilic attack, thus providing an alternative route to oligomerization.…”

Electrochemical and Spectroscopic Properties of Cation Radicals: III . Reaction Pathways of Carbazolium Radical Ions

“…3-Formyl-N-ethylcarbazole was obtained from Aldrich Chemical Company and purified by benzene chromatography on basic alumina followed by recrystallization from benzene/hexane, mp 88~ ~ [Ref. (30) 92~176 Wolff-Kishner reduction (25) and two recrystallizations from methanol yielded 3-methyl-N-ethylcarbazole, mp 43~ ~ [Ref. (25) 45"].…”

Preparation, characterization, two-photon absorption and optical limiting properties of a novel metal complex containing carbazole

“…p * and n ! p * transitions of the carbazole moiety [23,24]. Red-shift can be observed for the absorption bands of the carbazole ring upon complex formation.…”