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Molecular switches and dual channel detection of Cd 2+ and Fe 3+ ions based on a multipodand system
Author(s) -
Singh Prabhpreet
Publication year - 2021
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.4005
Subject(s) - molecular switch , protonation , ion , fluorescence , metal ions in aqueous solution , excimer , chemistry , metal , analytical chemistry (journal) , crystallography , molecule , physics , organic chemistry , chromatography , quantum mechanics
Multipodand conjugates were designed and synthesized and incorporated 5‐chloro‐8‐hydroxyquinoline for efficient performance and fine tuning to behave as molecular switches by the addition of metals ions, protonation, and their combination in CH 3 CN and CH 3 CN–H 2 O. Dipodand 3 and tetrapodand 4 showed a switching ‘ON’ of fluorescence (λ em = 435–445) with Zn 2+ and Cd 2+ (OR logic) and switching ‘OFF’ of fluorescence (λ em = 402) in the presence of Cu 2+ , Co 2+ and Ni 2+ (NOR logic). 4 showed switching ‘OFF’ of fluorescence at 402 nm at low concentrations of Ag + , Pb 2+ , Hg 2+ and Fe 3+ and, on further accumulation of these metal ions, excimer bands at 432 nm (Ag + ) and 510 nm (Pb 2+ , Hg 2+ and Fe 3+ ) provided the opportunity for ‘ON–OFF–ON’ switching. In contrast, 3 showed no change with Ag + , while Pb 2+ caused only ‘ON–OFF’ switching and Hg 2+ and Fe 3+ ions caused similar ‘ON–OFF–ON’ switching. The H + ‐induced ‘ON–OFF–ON’ molecular switch was combined with Cu 2+ that persuaded NOR logic to mimic inhibit (INH) logic. The compound also exhibited a H + /Cu 2+ ‐induced ‘OFF–ON–OFF’ type of signalling pattern. These proton‐induced multiple outputs provide opportunities for YES, NOT logic gates. 3 showed selective ‘ON–OFF’ behaviour with Fe 3+ ions and ‘OFF–ON’ behaviour with Cd 2+ ions in 20% HEPES buffer–CH 3 CN.