Push-pulling induces the excited-state intramolecular proton transfer in 2′-aminochalcones
作者:Cátia I.C. Esteves、Luís F.B. Fontes、A. Filipa N. Borges、João Rocha、Artur M.S. Silva、Samuel Guieu
DOI:10.1016/j.dyepig.2022.110275
日期:2022.6
electron-donating groups on one side, and electron-withdrawing groups on the amine, present dual emission ascribed to ESIPT between the keto-enamine and the enol-imine tautomers. The hydrogen bonds strength was studied by NMR and DFT calculations. A correlation between the tautomerization energy gap and the hydrogen bond strength was observed, depending on the electron donating or electron withdrawing group on
通常,查耳酮是不发光的,尽管它们具有推拉取代模式的衍生物可能会呈现出公平的量子产率. 氢供体(-OH 或 -NH)与查耳酮羰基之间的分子内氢键促进激发态分子内质子转移 (ESIPT)。如果染料是荧光的,则发射可以来自被激发的互变异构体之一,或者来自两者,在这种情况下观察到双重发射。在这里,具有强推拉特性的 2'-氨基查尔酮,在一侧结合给电子基团,在胺上结合吸电子基团,在酮-烯胺和烯醇-亚胺互变异构体之间呈现出归因于 ESIPT 的双重发射。通过NMR和DFT计算研究氢键强度。观察到互变异构化能隙和氢键强度之间的相关性,这取决于胺上的给电子基团或吸电子基团。与质子供体键合的吸电子基团对量子产率和发射波长的影响很小。相反,与质子受体相连的给电子基团对量子产率有显着影响,并引起吸收和发射红移。