Enantioselective fluorescent sensing of chiral carboxylic acid by engaging boronic acid and BINOL

• DOI: 10.1016/j.snb.2016.12.099
• Publication Date: 2016-12-24T14:01:47Z
• Authors: Sathish Kumar Mun...; Krishnan Thirumoo...; Vivek Panyam Mura...; Umamahesh Balijap...; Sathiyanarayanan ...
• Keywords: Mandelic acid; Boronic acid; Proton NMR

Two BINOL based boronate esters, namely (S)-2 and (S)-3, were designed and synthesized. Fluorescent recognition studies of (S)-2 towards enantiomers of mandelic acid revealed that sensor (S)-2 exhibited high fluorescent enantioselective response towards mandelic acid. The other boronate ester (S)-3 which did not have hydroxyl group in the minor groove of BINOL did not show any fluorescent chiral discrimination. Their enantioselective recognition was also studied by means of 1H NMR spectroscopy. The results indicated that the sensor (S)-2 was very promising as a chiral fluorescent sensor for the recognition of chiral carboxylic acid in THF solvent. Theoretically predicted hydrogen bonding interactions revealed a favorable chiral recognition between the receptor and l-mandelic acid, which is well correlated with experimentally observed enantioselective recognition phenomenon.