Alternating Conjugated and Transannular Chromophores: Tunable Property of Fluorene-Paracyclophane Copolymers via Transannular π−π Interaction
摘要:
GraphicsA series of fluorene-dithia[3.3]paracyclophane copolymers was synthesized by Suzuki coupling reactions of suitable precursors. Transannular pi-pi interactions altered the electronic and optical properties of the polymer backbone significantly. A large red shift in the emission spectrum of the unsubstituted polymer was accompanied by enhanced photoluminescence (PL) efficiency. Substitution in the cyclophane unit resulted in PL quenching.
Synthesis and photophysics of new pyridyl end-capped 3D-dithia[3.3]paracyclophane-based Janus tectons: surface-confined self-assembly of their model pedestal on HOPG
作者:Nicolai Stuhr-Hansen、Edwin H. A. Beckers、Lars Engman、René A. J. Janssen
DOI:10.1002/hc.20167
日期:——
A new type of conjugated polymer, organoselenium substituted poly(p-phenyleneviny- lene) (PPV), was synthesized from the corresponding alkylselenenyl p-xylylene dibromide via a Gilch route using potassium tert-butoxide in THF. The p-xylylene dibromide precursors were synthesized by reacting lithiated bis(methoxymethyl)benzenes with elemental selenium, followed by alkylation of the generated selenolates
Bedard, Thomas C.; Moore, Jeffrey S., Journal of the American Chemical Society, 1995, vol. 117, # 43, p. 10662 - 10671
作者:Bedard, Thomas C.、Moore, Jeffrey S.
DOI:——
日期:——
Electrophilic organic selenium reagents—protonated seleninic acids as precursors for unsymmetrical aromatic selenides
作者:Nicolai Stuhr-Hansen、Theis Ivan Sølling、Lars Henriksen
DOI:10.1016/j.tet.2011.02.004
日期:2011.4
Arylselenylations of methylbenzenes, methoxybenzenes and thiophene were smoothly achieved with selenenium ions generated by comproportionation of 1:1 mixtures of p-toluenesulfonic acid salts of seleninic acids and the corresponding diselenides. A series of p-toluenesulfonic salts of seleninic acids were prepared by hydrogen peroxide oxidation of the corresponding diselenides in the presence of p-toluenesulfonic acid. Novel 2-(organylseleno)thiophenes were obtained by heating the protonated seleninic acids with a 50-fold excess of thiophene in glacial acetic acid. (C) 2011 Published by Elsevier Ltd.
Novel Synthesis of Protected Thiol End-Capped Stilbenes and Oligo(phenylenevinylene)s (OPVs)
作者:Nicolai Stuhr-Hansen、Jørn B. Christensen、Niels Harrit、Thomas Bjørnholm
DOI:10.1021/jo0263770
日期:2003.2.1
The first general procedures for preparation of thiol end-capped stilbenes and oligo(phenylene-vinylene)s (OPVs) with tert-butyl- and acetyl-protected thiol termini have been developed. These reactions proceed via Br/Li exchange, McMurry, and Wittig-type reactions. The thiol functionality is protected against strong basic and acidic reaction conditions as a t-Bu sulfide. As a key point in the method, reprotection of the thiol group is accomplished by means of acetyl chloride and boron tribromide. The novel strategy forms the basis for stepwise introduction of 4-mercaptostyryl units in OPVs. The new mono-, di-, and trimercapto OPVs have potential applications as one, two, and three terminal molecular devices in gold nanoparticle clusters, self-assembled monolayers, and optoelectronic devices.
Alternating Aromatic and Transannular Chromophores with and without Linker: Effect of Transannular π−π Interaction on the Optical Property of Dithiaparacyclophane-based Copolymers
作者:Weiling Wang、Jianwei Xu、Yee-Hing Lai、Fuke Wang
DOI:10.1021/ma035902+
日期:2004.5.1
A series of bithiophene-cyclophane (PPP-type), acetylene-fluorene-acetylene-cyclophane (PPE-type), and ethylene-fluorene-ethylene-cyclophane (PPV-type) copolymers, namely, 4-6, was synthesized via a nickel-catalyzed reaction, a palladium-catalyzed Sonagashira reaction, and a Heck coupling, respectively. Unlike in the fluorene-cyclophane copolymer 3, the transannular pi-pi interaction of the cylophane unit in copolymer 4 resulted in a significant blue shift in its emission spectrum compared to a reference polymer, giving it an essentially blue emitting light. By introducing an acetylene or ethylene linker in going from 3 to 5 or 6, the effective conjugation in the polymer backbone due to higher rigidity in coplanarity decreased the effect of the transannular pi-pi interaction. While the PPV-type copolymer 6 still exhibited an appreciable red shift in both absorption and emission with respect to a reference polymer, negligible shifts were observed for copolymer 5.