A new linear phenyloxazole-benzothiadiazole luminophore: crystal growth, structure and fluorescence properties.
Acta Crystallogr B Struct Sci Cryst Eng Mater
; 78(Pt 2): 261-269, 2022 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-35411864
ABSTRACT
A new linear luminophore consisting of five conjugated units of oxazole, phenylene and a central benzothiadiazole fragment, 4,7-bis[4-(1,3-oxazol-5-yl)phenyl]-2,1,3-benzothiadiazole, has been synthesized and characterized. Needle-like single-crystal samples up to 10â
mm in length were obtained by physical vapor transport. The crystal structure was determined at 95â
K and 293â
K using single-crystal X-ray diffraction. With decreasing temperature, the space group P21/n does not change, but the unit-cell volume of the crystal decreases. The presence of intra- and intermolecular hydrogen bonds was established. Melting parameters (Tm = 305.5°C, ΔHm = 52.2â
kJâ
mol-1) and the presence of a liquid-crystalline mesophase (TLC = 336.3°C, ΔHLC = 1.4â
kJâ
mol-1) were determined by differential scanning calorimetry and in situ thermal polarization optical microscopy studies. The presence of linear chains of hydrogen bonds ensures high stability of the crystal structure in a wide temperature range. The luminophore is characterized by a large Stokes shift (5120-5670â
cm-1) and a high quantum yield of fluorescence, reaching 96% in solutions (λmax = 517â
nm) and 27% in thin crystalline films (λmax = 529â
nm). The calculated absorption and emission spectra are in good agreement with the experimental data. Because of the excellent optical properties and high thermal stability, the new linear luminophore has great potential for application in organic photonics and optoelectronic devices.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cristalização
Idioma:
En
Revista:
Acta Crystallogr B Struct Sci Cryst Eng Mater
Ano de publicação:
2022
Tipo de documento:
Article