A Urea-Functionalized Chemoreceptor for Expeditious Chromogenic Recognition of Toxic Industrial Pollutants Cu²⁺ and CN^– from Real Water Sources and Biofluids: Diagnosis of Wilson’s disease from Human Urine

Abstract

A urea-functionalized chemoreceptor 1,5-bis(2,4dinitrophenyl)carbonohydrazide (BDC) with versatile applications has been reported in this work. BDC displayed ditopic sensitivity toward toxic industrial pollutants Cu 2+ and CN − from a purely aqueous medium. BDC has been structurally authenticated by ESI-MS, 1 H-NMR, FT-IR, and SCXRD. It can undergo promising "naked eye" detection in the existence of the targeted analytes (pale yellow to dark purple for Cu 2+ and pale yellow to dark brown for CN − ) in the sub-nanomolar detection threshold (Cu 2+ : 46 × 10 −8 M and CN − : 92 × 10 −8 M). The LMCT-ICT and intermolecular H-bonding pathways rationalize the underlying sensing mechanism. A good substantiation of solution-state experimental outcome and theoretical (DFT) evidence further authenticated the recognition pathway. BDC displays reversibility with alternate CN − and Cd 2+ addition up to several cycles that serves to be a reliable system toward mimicking molecular logic gate functions. The cytotoxicity assay of BDC on Bacillus thuringiensis (Bt) exhibit its biocompatibility. Furthermore, BDC can efficiently undergo rapid on-site Cu 2+ and CN − detection in varying real water sources, and interestingly, BDC can recognize the presence of Cu 2+ from biofluids like fetal bovine serum (LOD 13 μM) with a distinct colorimetric response. Moreover, the unprecedented novelty of biocompatible BDC lies in its ability to detect Cu 2+ from a human urine specimen as low as 1.5 μM by concentration-dependent discriminative chromogenic responses. This makes BDC an inimitable exploratory symptomatic tool for Wilson's disease, which to the best of our knowledge to date has been rarely explored in the supramolecular realm. One step ahead, solid-state on-spot chromogenic detection of aqueous Cu 2+ and CN − by the "dip stick" method escalates the practical application of this work.

Trace-Level Humidity Sensing from Commercial Organic Solvents and Food Products by an AIE/ESIPT-Triggered Piezochromic Luminogen and ppb-Level “OFF–ON–OFF” Sensing of Cu2+: A Combined Experimental and Theoretical Outcome

“…Thus, it could be predicted that NAP-1 maintains 1:1 binding stoichiometry with Cu 2+ . The corresponding association constant for 1:1 binding stoichiometry was obtained to be 2.34 × 10 8 M –1 from the Benesi–Hildebrand equation (Figure S24, SI). To investigate the response rate of NAP-1 toward Cu 2+ , a time-dependent study has been carried out using Cu 2+ of different concentrations.…”

Recent endeavours in the development of organo chromo-fluorogenic probes towards the targeted detection of the toxic industrial pollutants Cu2+ and CN−: recognition to implementation in sensory device

“…Banerjee et al described urea-based probe 6, which displayed discriminative chromogenic changes from pale yellow to dark purple for Cu 2+ . 34 6 displayed a sub-nanomolar detection threshold (46 Â 10 À8 M) in purely aqueous medium. With the steady addition of Cu 2+ to 6, the initial peak of 6 (335 nm) was diminished with the synchronous generation of a new peak at 550 nm, rationalizing a plausible CT from the filled molecular orbital of 6 towards the vacant d 9 orbital of Cu 2+ via the ligandto-metal charge transfer phenomenon (LMCT).…”

“…Banerjee et al revealed that urea-based probe 6 34 exhibited a distinct “naked-eye” response towards CN − in purely aqueous medium with a detection threshold of 92 × 10 −9 M. The ICT and intermolecular H-bonding interaction between the –NH and –CH protons in 6 with the target CN − analyte was rationalized as the underlying recognition phenomenon. 6 displayed reversibility with alternating CN − and Cd 2+ , which served as an absolute and reliable platform towards mimicking a molecular logic gate-based ensemble (Fig.…”

Zn2+ Recognition for Pathogenesis of Pick's Disease via a Luminescent Test Kit

“…L1 displayed four signals at 220, 250, 325 with a broad signal at 415 nm due to π-π*, n-π* and charge transfer transition within the framework respectively. The absorption spectra of L1 in acetonitrile: HEPES (4 : 1, v/v, conc n : 2 × 10 À 5 M, pH 7.4) [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] (λ max /nm; ε/M À 1 cm À 1 ): 325 (18100) and for L1-Zn 2 + (λ max /nm; ε/M À 1 cm À 1 ): 370 (11100) respectively (Figure S5a-b). Photoexcitation at 400 nm gives fluorescence of L1 (conc n : 5 × 10 À 6 M, pH 7.4) at 495 nm which reveals a Stokes Shift of 80 nm.…”