Observation of a non-conventional Horner–Wadsworth–Emmons olefination product and the effect of the lateral ethyl substitution on the solid state fluorescence
Observation of a non-conventional Horner–Wadsworth–Emmons olefination product and the effect of the lateral ethyl substitution on the solid state fluorescence
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非常规 Horner-Wadsworth-Emmons 烯化产物的观察以及横向乙基取代对固态荧光的影响
DOI：
10.1039/b408748h
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发表时间：
2004
影响因子：
3.3
通讯作者：
Suresh Das
中科院分区：
文献类型：
--
作者：
R. Davis;Shibu Abraham;N. Rath;Suresh Das
1-（对甲氧基苯基）-4-（对氰基苯基）丁-1E，3E-二烯（MCB）和1-（对N，N-二甲氨基苯基）-4-（对氰基苯基）丁-1E，3E-二烯（ACB）在固体中的荧光性质明显不同于在溶液中的荧光性质。在固态下观察到的红移吸收和发射光谱归因于J聚集体的形成。通过Horner-Wadsworth-Emmons反应制备这些衍生物，其中通过用亚磷酸三乙酯处理对氰基苄基溴获得的膦酸酯与相应的肉桂醛缩合，也产生非常规的烯化产物1-对甲氧基苯基（对氰基苯基）-4-（乙基）丁-1E，3E-二烯（MCBE）和1-（对-N，N-二甲基氨基苯基）-4-（对-氰基苯基）-4-（乙基）丁-1E，3E-二烯（ACBE），其丁二烯链上带有乙基取代基。这些产物的形成表明在最初形成的膦酸酯中乙基从氧中心到苄基位置的碱催化的1，3-迁移。观察到在另外的平面分子中乙基的存在显著阻碍固态中的聚集，导致即使在其本体状态下也产生分子样荧光。
Donor-acceptor-substituted diphenylbutadienes, namely 1-(p-methoxyphenyl)-4-(p-cyanophenyl)buta-1E,3E-diene (MCB) and 1-(p-N,N-dimethylaminophenyl)-4-(p-cyanophenyl)buta-1E,3E-diene (ACB) exhibit fluorescence properties in their solid that are distinctly different from their fluorescence in solution. The red-shifted absorption and emission spectra observed in the solid state are attributed to the formation of J aggregates. Preparation of these derivatives via a Horner–Wadsworth–Emmons reaction, wherein the phosphonate obtained by treating p-cyanobenzyl bromide with triethyl phosphite was condensed with corresponding cinnamaldehydes, also yielded the non-conventional olefination products 1-(p-methoxyphenyl)-4-(p-cyanophenyl)-4-(ethyl)buta-1E,3E-diene (MCBE) and 1-(p-N,N-dimethylaminophenyl)-4-(p-cyanophenyl)-4-(ethyl)buta-1E,3E-diene (ACBE), which bear an ethyl group substituent on their butadiene chain. The formation of these products suggests a base-catalyzed 1,3-migration of an ethyl group from an oxygen center to the benzylic position in the initially formed phosphonate. The presence of the ethyl group in an otherwise planar molecule was observed to significantly hinder aggregation in the solid state, resulting in molecule-like fluorescence even in their bulk state.