Novel triene merocyanines, i.e. 1-styryleth-2-enylidene and 4-(1,3,3-trimethylindolin-2-ylidene)but-2-en-1-ylideneindolones are obtained in good to excellent yields in a consecutive three-component insertion Sonogashira coupling–addition sequence. The selectivity of either series is remarkable and has its origin in the stepwise character of the terminal addition step as shown by extensive computations on the DFT level. All merocyanines display intense absorption bands in solution and the film spectra indicate J-aggregation. While 1-styryleth-2-enylideneindolones show an intense deep red emission in films, 4-(1,3,3-trimethylindolin-2-ylidene)but-2-en-1-ylideneindolones are essentially nonemissive in films or in the solid state. TD-DFT computations rationalize the charge-transfer nature of the characteristic broad long-wavelength absorptions bands.
通过连续的三组分插入Sonogashira偶联-加成序列,可以获得新型
三烯基美洛色烯,即1-
苯乙烯基-2-烯基亚甲基和4-(1,3,3-三甲基
吲哚-2-亚甲基)丁-2-烯-1-亚甲基
吲哚酮,收率良好至极佳。两个系列的选择性非常显著,其起源在于末端加成步骤的逐步特性,这一点通过在DFT
水平上进行广泛的计算得到证明。所有美洛色烯在溶液中显示出强烈的吸收带,薄膜光谱表明存在J-聚集。虽然1-
苯乙烯基-2-烯基亚甲基
吲哚酮在薄膜中显示出强烈的深红色发射,但4-(1,3,3-三甲基
吲哚-2-亚甲基)丁-2-烯-1-亚甲基
吲哚酮在薄膜或固态中基本上不发射。TD-DFT计算说明了特征宽长波长吸收带的电荷转移性质。