New boron compounds selectively detect cyanide, opening sensor market
Researchers created custom boron-based molecules that bind cyanide more strongly than competing ions, a capability that could enable better detection systems for environmental and industrial monitoring. The approach systematically tunes molecular properties through a simple chemical modification, potentially accelerating development of next-generation chemical sensors.
Originaltitel: Tetrazole-Functionalized Organoboranes Exhibiting Dynamic Intramolecular NâB-Coordination and Cyanide-Selective Anion Binding
<p>Starting from two different cyano-functionalized organoboranes, we demonstrate that 1,3-dipolar [3+2] azide-nitrile cycloaddition can serve to generate libraries of alkyl-tetrazole-functionalized compounds capable of intramolecular N -> B-Lewis adduct formation. Due to the relatively low basicity of tetrazoles, structures can be generated that exhibit weak and labile N -> B-coordination. The reaction furnishes 1- and 2-alkylated regio-isomers that exhibit different effective Lewis-acidities at the boron centers, and vary in their optical absorption and fluorescence properties. Indeed, we identified derivatives capable of selectively binding cyanide over fluoride, as confirmed by 11B NMR. This finding demonstrates the potentialities of this synthetic strategy to systematically fine-tune the properties of lead structures that are of interest as chemical sensors. Cyano-functionalities in organoboranes have been converted into tetrazoles. The chemical modification allows to tailor the Lewis-acidity of the boron center through intermolecular N -> B-interaction. As a result, the compounds exhibit significantly altered physical properties, including selective binding of Cyanide over Fluoride. image</p>