Rhodamine dyes have several applications based on properties, such as high molar absorptivity, high fluorescence quantum yield, photostability, absorption and emission wavelengths in the visible region. In this paper, we describe the solvent‐free synthesis of rhodamines between m‐aminophenol derivatives (3‐dimethylamino and 3‐diethylaminophenol) and phthalic anhydride derivatives (with and without halogens in the benzene ring) using Nb₂O₅ as catalyst. The compounds were produced in high yields (79 to 90%) within one hour of reaction time and with catalyst recovery. Additionally, a solvatochromic study of rhodamine derivatives was described. These compounds have absorption and emission bands at wavelengths in the visible region and a high quantum yield that potentially makes them good dyes for use in electronic devices (e. g. lasers, OLEDs). The DFT calculations provided a basis for understanding the effect of the solvent on the structural forms of rhodamine and corroborated with the experimental data, where the zwitterionic form is predominant in polar solvents, while in apolar solvents the lactonic form is the most stable.

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Nb2O5的无溶剂合成及新型罗丹明染料溶剂效应的理论和实验研究

罗丹明染料基于性质具有多种应用，例如高摩尔吸收率，高荧光量子产率，光稳定性，可见光区域的吸收和发射波长。在本文中，我们描述了罗丹明之间的无溶剂合成米氨基苯酚衍生物（3-二甲基氨基和3-二乙氨基）和邻苯二甲酸酐衍生物（具有和不具有在所述苯环的卤素），使用的Nb ₂ ö ₅作为催化剂。在反应时间一小时内以高收率（79％至90％）生产化合物，并回收催化剂。另外，描述了若丹明衍生物的溶剂溶变色研究。这些化合物在可见光区域的波长处具有吸收和发射带，并且具有高的量子产率，这潜在地使它们成为用于电子设备（例如激光器，OLED）的良好染料。DFT计算为理解溶剂对罗丹明结构形式的影响提供了基础，并与实验数据相佐证，其中两性离子形式在极性溶剂中占主导，而在非极性溶剂中内酯形式最稳定。