Chemoselective Detection of 2, 4, 6‐trinitrophenol by Ground State Adduct Formation via Protonation of Quinoline Moiety of Non‐heme Ligands with Structural Evidence. Issue 28 (24th July 2020)

• Record Type: Journal Article
• Authors: Harmalkar, Sarvesh S.; Naik, Ankita V.; Nilajakar, Madhuri K.; Dhuri, Sunder N.
• Is Part Of: ChemistrySelect. Volume 5:Issue 28(2020)
• Page Start: 8447
• Page End: 8454
• Publication Date: 2020-07-24
• Subjects: Chemoselective -- Fluorescence -- Quenching -- TNP -- Explosives -- Crystal structures -- Protonation -- Static Quenching.; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202002244
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Four quinoline based non‐heme tetradendate ligands viz. N, N′ ‐di(quinolin‐8‐yl)ethane‐1, 2‐diamine (BQENH2 ) 1, N, N′ ‐di(quinolin‐8‐yl)propane‐1, 3‐diamine 2 (BQPNH2 ), N, N′ ‐di(quinolin‐8‐yl)butane‐1, 4‐diamine (BQEBNH2 ) 3 and N, N′ ‐di(quinolin‐8‐yl)hexane‐1, 6‐diamine (BQEHNH2 ) 4 are structurally characterized and used in selective detection of 2, 4, 6‐trinitrophenol (TNP) with high quenching constants. The plausible reaction mechanism involves ground state protonation of quinoline nitrogen atoms in compounds 1–4 by TNP with formation of picrate adducts (1 a ‐4 a ). The protonation of 1–4 is confirmed by infrared, 1 H‐NMR spectroscopies, powder XRD and the single crystal structure analysis of 1 a and 4 a . Crystal structures further infer that after protonation, 1 a and 4 a are stabilized by intramolecular hydrogen bonding. Abstract : Four fluorescent compounds were investigated in the sensing of nitrophenol derivatives which showed promising results with high sensitivity in the detection of 2, 4, 6‐trinitrophenol over others. With the help of spectroscopic and structural evidence, we have shown the ground state adduct formation via protonation which leads to quenching of fluorescence.