Pyridylazo Derivatives with Dicyanovinyl Appendage in Selective Sensing of CN- in Sol-Gel Medium

摘要

abstract_textpPyridyl azo-based dicyanovinyl coupled chemosensors 1 and 2 have been designed and synthesized. While compound 1 with phenolic -OH is reluctant to form gel, the phenol ether 2, under identical conditions, forms gel in CH3CN. The morphology of the gel indicates closely packed globular microstructure. The rheological study corroborates the significant elastic character of the gel. The gel is thermo reversible and is converted to sol selectively in presence of CN- ions involving nucleophilic addition to the dicyano activated olefinic bond and validates the visual sensing of CN-. Such type of CN- sensing using supramolecular gelators, comprised of dicyano activated olefinic bond, is unknown in the literature although solution phase sensing of the same anion with the molecular receptors having dicyano substituted olefinic segment is quite explored. In addition to gel phase sensing, the gelator 2 selectively senses CN- ions in solution by exhibiting turn on' emission change with detection limit of 9.36 x 10(-6) M./p/abstract_text