Carbanion‐Induced Skeletal‐Rearrangements: From the Dibenzo[a,e] cyclooctene to the Indeno[2,1‐a]indene Framework

Abstract

A surprising ring contraction to give derivatives 2 and 3 of indeno[2, 1‐a]indene is observed in the reaction of 1 with organolithium compounds (R = alkyl, Ph; R1, R2 = H, alkyl, Ph). The expected nucleophilic substitution of 1 has so far only been accomplished in one case: with CuCN, the tetracarbonitrile 1, CN instead of Br, is formed.

Synthesis, structures, and photophysical properties of silicon and carbon-bridged ladder oligo(p-phenylenevinylene)s and related π-electron systems

“…The insoluble material was removed by filtration and the filtrate was concentrated under C 138 H 158 Si 4 : C,85.92;H,8.26. Found: C,85.41;H,8.29%.…”

“…However, only a limited attention has been paid to the phenylenevinylene-based ladder molecules, probably due to their difficult synthesis [6]. For example, whereas the simplest methylene-bridged stilbene 1 is well known to show an intense fluorescence with the quantum yield of nearly unity [7], its synthesis has not been improved from its original report [8] and no related work has been reported on the synthesis of its higher oligomers or polymers.…”

Emission from Charge Recombination during the Pulse Radiolysis of Bis(diarylamino)dihydro-indenoindene Derivatives

“…First, R-DI have the diarylamino groups and trans -stilbene moiety to localize the corresponding radical cations and anions, which is desirable for the intermolecular electron transfer, leading to the efficient charge recombination. Second, with the addition of the perpendicular butterfly-shaped phenyl groups, R-DI have a more bulky structure, leading to the higher thermal stability and emission efficiency . Third, the τ 1/2 of each R-DI •+ is longer than that of the corresponding R-DI •– , which implies that all R-DI •+ have a slower neutralization process via the collision between the radical cations and chloride ion in DCE solution.…”

Bis-Silicon-Bridged Stilbene Homologues Synthesized by New Intramolecular Reductive Double Cyclization

“…The photophysical data of the silicon-bridged stilbene homologues are summarized in Table , together with the data of 1a (R = Me), for comparison. There are a couple of notable points: (1) The silicon-bridge significantly shifts the absorption and emission maxima to a longer wavelength.…”

“…This fact suggests that the π-conjugation is effectively extended over the entire molecule. The photophysical data of the silicon-bridged stilbene homologues are summarized in Table 1, together with the data of 1a (R ) Me), 14 for comparison. There are a couple of notable points:…”