Two are better than one - Synthesis of novel blue and green emissive hydroxy-oxadiazoles

A Synthetic Approach for Oxadiazole‐Decorated Azobenzene Photoswitches

“…Compounds 5 a and 5 b were initially screened for their optical and electronic properties. The UV‐vis spectra indicated absorption maximum at λ max =330 nm for 5 a and two absorption maxima at λ max =293 nm and λ max =345 nm for 5 b , characteristic for π–π* transitions of the oxadiazole core, with large values of the molar absorption coefficients, around 24.500 Mol −1 cm −1 [19,30] …”

“…The fluorinated compound 1 d (Scheme 3) was obtained in excellent yield (94 %) by Mills reaction of compound 5 a and 2,6-difluoro-nitrosophenyl 8, resulted by oxidation 2,6-difluoroanilline 7 with Oxone, using a slightly modified previously described procedure. [28] The synthesized compounds were screened using thermogravimetric analysis, considering well-known behaviour of oxadiazole-based compounds, [18][19][20] and the results indicated very high thermal stability over a wide range of temperatures. The decomposition curves have a similar shape, with a single degradation step for all compounds.…”

“…[15][16][17] 1,3,4-Oxadiazole-based compounds hold very good luminescent properties and by appropriate structural modification a wide range of emissive colours could be obtained, enabling studies for fluorescence-based applications. [18][19] Although they have been long-lasting recognised for applications in organic LEDs production, [18] sensing of metal-ions or anions based on enhancement or quenching of fluorescence have also been reported. [20] During the course of our work, the idea to combine properties of oxadiazole core with a switching unit, like azo group, seemed promising to achieve light-emissive switching molecules.…”

Solid-state emitters presenting a modular excited-state proton transfer (ESIPT) process: recent advances in dual-state emission and lasing applications

“…36 A double H-bonded 2,2 0bipyridine-3,3 0 -diol-5,5 0 -dicarboxylic acid ethyl ester has been reported as a single ESIPT emitter while the other hydrogen bond participates in the rigidification of the overall scaffold, making this dye suitable for an insertion in OLED devices. 37 Other examples include 2,5-disubstituted-1,3,4-oxadiazoles 38 and most importantly red/NIR emissive squaraine derivatives. 39 Guided by TD-DFT calculations, the authors demonstrate that the removal a simple phenyl ring led to intense red/NIR emissions in solution and in crystals.…”

2‐(1,2,4‐Oxadiazol‐5‐yl)aniline as a New Scaffold for Blue Luminescent Materials

“…Conjugated polyaromatic systems such as fluorene, [15,16] carbazole, [17][18][19] coumarin, [20,21] pyrene, [22,23] substituted thiophenes, [24,25] and 1,3,4-oxadiazoles [26,27] have long established themselves as valuable fluorescent scaffolds. At the same time, 1,2,4-oxadiazole derivatives as a basis for luminescent materials have been studied much less.…”