Selective detection of Cu²⁺ in aqueous medium using an acid hydrazide-based chemosensor: experimental and DFT/TDDFT...

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Selective detection of metal ions is crucial for environmental monitoring and biological studies.
• Copper(II) ions (Cu2+) play vital roles in biological systems but can be toxic at elevated levels.
• Development of sensitive and selective chemosensors for Cu2+ detection is an active research area.

Purpose of the Study:

• To design and synthesize a novel acid hydrazide-based Schiff base, N'-(4-hydroxybenzylidene)picolinohydrazide (HP).
• To investigate the potential of HP as a selective chemosensor for Cu2+ ions.
• To evaluate the sensing performance, binding mechanism, and practical applicability of the HP probe.

Main Methods:

• Synthesis of HP via a single-step process.
• Structural characterization using FTIR, NMR (1H, 13C), HRMS, SCXRD, and elemental analysis.
• Cation-sensing studies using UV-Vis spectroscopy, Job's plot analysis, and FESEM.
• Computational analysis including DFT and TD-DFT.

Main Results:

• HP was successfully synthesized and characterized.
• HP exhibited rapid, selective, and sensitive detection of Cu2+ in MeOH/H2O with a detection limit of 8.94 µM.
• Job's plot confirmed a 1:1 binding stoichiometry with an association constant of 4.26 × 10^4 M^-1.
• Morphological changes were observed via FESEM upon Cu2+ coordination.
• DFT calculations supported the experimental findings, revealing LE and ICT characteristics.

Conclusions:

• The synthesized HP probe is effective for the selective and sensitive detection of Cu2+ ions.
• The probe demonstrates practical applicability for Cu2+ detection in real water samples.
• HP shows promise as a valuable tool in analytical chemistry for metal ion sensing.