Tewary D, Behera KC, Turner DR, Ravikanth M. Synthesis of pyridyl functionalized 3-pyrrolyl BODIPY based fluoroprobes and application towards highly selective detection of picric acid.
Phys Chem Chem Phys 2024;
26:22479-22490. [PMID:
39145604 DOI:
10.1039/d4cp02715a]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
A series of pyridyl-coupled 3-pyrrolyl BODIPY fluoroprobes were synthesized by varying the position of the pyridyl/N-methylated pyridyl group at the α-/meso-position of the 3-pyrrolyl BODIPY scaffold and thoroughly characterized by HRMS and 1D/2D NMR techniques. Our studies indicated that only the water-soluble N-methylated p-pyridyl 3-pyrrolyl BODIPY among various pyridyl-coupled 3-pyrrolyl BODIPYs synthesized here showed an effective and exclusive sensing for picric acid (HPA). The N-methylated p-pyridyl 3-pyrrolyl BODIPY rapidly detects HPA in an aqueous medium with exceptional selectivity, sensitivity (LOD = 7.90 pM), and high binding affinity (Ka = 4·94 × 108 M-1) through both chromogenic and fluorogenic signalling modes. Our studies support the formation of a charge transfer complex between cationic N-methylated p-pyridyl 3-pyrrolyl BODIPY and picrate as verified by absorption, fluorescence, electrochemical, and NMR techniques. DFT and TD-DFT studies further support the structural and experimental observations, including the sensing mechanism of HPA.
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