Crystallographic Elucidation of Stimuli-Controlled Molecular Rotation for a Reversible Sol-Gel Transformation.
J Org Chem
; 85(6): 4019-4025, 2020 Mar 20.
Article
em En
| MEDLINE
| ID: mdl-32077292
ABSTRACT
To get an idea about the most probable microporous supramolecular environment in the gel state, gelator molecule 1 has been crystallized from its gelling solvent (dimethylformamide). Crystal structure analysis of 1 shows a strong π···π stacking interaction between the electron-deficient pentafluorophenyl ring and electron-rich naphthyl ring. The gelling solvent situated in the "molecular pocket" stitches the gelators through weak H-bonding interactions to facilitate the formation of an organogel. Scanning electron microscopy analysis exhibits a ribbonlike fibrous morphology that resembles the supramolecular arrangement of 1 in its crystalline state, as evidenced by powder X-ray diffraction. In the presence of external stimuli (tetrabutylammonium fluoride), the organogel of 1 disassembles into sol. This sol-gel transformation phenomenon has been explained on the basis of X-ray single-crystal analysis. Single crystals obtained from the sol state show that naphthylic -OH of 1 gets deprotonated, resulting in C-C bond rotation that plays a major role in the sol-gel transformation. Gelator 1 exhibits weak green fluorescence in the gel state, whereas it shows highly intense yellow fluorescence in the sol state. Furthermore, a reversible sol-gel transformation associated with changes in the spectroscopic properties has been observed in the presence of acids and fluoride ions, respectively.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Índia