Sequential Fluorescence Recognition of Molybdenum(VI), Arsenite, and Phosphate Ions in a Ratiometric Manner: A Facile Approach for Discrimination of AsO₂^–and H₂PO₄^–

Abstract

An amide-based smart probe (L) is explored for nanomolar detection of Mo(VI) ion in a ratiometric manner, involving hydrogen-bond-assisted chelation-enhanced fluorescence process through inhibition of photoinduced electron transfer process. The recognition of Mo(VI) is associated with a 17-fold fluorescence enhancement and confirmed by single-crystal X-ray diffraction of the resulting Mo(VI) complex (M1). Further, M1 selectively recognizes arsenite through green emission of their adduct (C1) with an 81-fold fluorescence enhancement. Interestingly, dihydrogen phosphate causes dissociation of C1 back to free L having weak fluorescence. The methods are fast, highly selective, and allow their bare eye visualization at physiological pH. All of the interactions have been substantiated by time-dependent density functional theory calculations to rationalize their spectroscopic properties. The corresponding lowest detection limits are 1.5 × 10 –8 M for Mo(VI), 1.2 × 10 –10 M for AsO 2 – , and 3.2 × 10 –6 M for H 2 PO 4 – , whereas the respective association constants are 4.21 × 10 5 M –1 for Mo(VI), 6.49 × 10 4 M –1 for AsO 2 – , and 2.11 × 10 5 M –1 for H 2 PO 4 – . The L is useful for efficient enrichment of Mo(VI) from aqueous solution, while M1 efficiently removes AsO 2 – from environmental samples by solid-phase extraction.

An Unsymmetrical bis‐Imine Derivative for Solvent Dependent Rapid Optical Discrimination of Al3+, Zn2+ and OCl−: Combined Experimental and Theoretical Studies

“…[1][2][3] In addition, the role of solvent towards the selectivity and sensitivity of detection is noteworthy. [4][5] The function of a sensor may involve several types of interactions between host and guest like hydrogen bonding, probe-cation coordination, aggregation, electrostatic interaction, hydrophobic and van der Waal's interactions etc. [6][7][8] A single probe having significantly different response towards multiple ions is cost effective, time saving and hence, highly desirable for practical application.…”

“…Development of smart organic probe for quick and selective detection of multiple bio‐ and environment relevant ions has attracted significant attention in contemporary research [1–3] . In addition, the role of solvent towards the selectivity and sensitivity of detection is noteworthy [4–5] . The function of a sensor may involve several types of interactions between host and guest like hydrogen bonding, probe‐cation coordination, aggregation, electrostatic interaction, hydrophobic and van der Waal's interactions etc [6–8] .…”

Mo(vi) complexes of amide–imine conjugates for tuning the selectivity of fluorescence recognition of Y(iii) vs. Pb(ii)

“…43 Oxo-molybdenum(VI) complexes have interesting stereochemical and microelectronic properties 44 having therapeutic and catalytic applications, possibly due to their switching ability amongst various oxidation states. 45 As far as the literature is concerned, reports on simultaneous, selective optical recognition of Y 3+ and Pb 2+ are unavailable. Only a very few reports on Y 3+ coordination chemistry/extraction are available.…”

“… 43 Oxo -molybdenum( vi ) complexes have interesting stereo-chemical and microelectronic properties 44 having therapeutic and catalytic applications, possibly due to their switching ability amongst various oxidation states. 45 …”

Tetraphenylethylene-Based Tetradentate Azolium Salts: Synthesis and Selective Recognition for Ions

“…[11][12][13] For example, the probes using urea groups or amide groups as binding sites have big association constant values (10 5 ～10 8 L•mol -1 ). [14][15][16] Also, metal organic frameworks (MOFs) or triazolium types of probes have good recognition ability for dihydrogen phosphate. [17][18] In addition, silver is an element with bactericidal function.…”