A selective detection approach for copper(ii) ions using a hydrazone-based colorimetric sensor: spectroscopic and DFT study

Abstract

The development of an efficient and miniaturized analytical approach to determine trace levels of toxic ions in aqueous fluids presents a current research challenge. Hydrazone-based chemosensors are considered potential candidates due to their high sensitivity and selectivity towards heavy metal ions. Computational techniques can be properly implemented to elucidate possible modes of ligand-metal interaction and provide an in-depth understanding of the chemistry involved. The present study reports the use of 3hydroxy-5-nitrobenzaldehyde-4-hydroxybenzoylhydrazone (3-HNHBH) ligand for highly sensitive, quick and re-usable colorimetric sensing of copper(II) ions in aqueous media. DFT calculations suggest that the complexation of 3-HNHBH with copper(II) ions adopts a seesaw coordination geometry and results in the largest HOMO-LUMO gap and most effective coulombic interaction compared to Zn and Ni counterparts. It demonstrated a high selectivity towards copper ions with a detection limit of 0.34 mg L À1 . The ligand was readily regenerated using a 0.5 M HCl solution, indicating its feasibility to be used as a re-usable sensor for the convenient detection of copper ions in aqueous media. The influence of metal interference, pH and solvents on the selectivity and regeneration of the ligand was also investigated.

Porous Fluorocarbon from Rice Husk for the Efficient Separation of Gases

“…The charge transfer characteristics of any two interacting molecules are determined by the spatial orientation of their frontier orbitals, and the energy gap maintained therein. [ 47 ] Molecules having lower energy gaps exhibits higher charge transfer characteristics and are therefore predicted to be more reactive. Frontier orbital distribution of the adsorbents (Figure 12b ) showed that the HOMO‐LUMO orbitals were adequately distributed across the molecules.…”

Addressing Multiple Ions Using Single Optical Probe: Multi‐Color Response via Mutually Independent Sensing Pathways

“…The structure of Compound 1 was first energy minimized using B3LYP/6‐31 G* level of theory (Figure a‐c). And the 1 + Zn 2+ adduct as well as desillylated product were independently optimized under similar condition to explain metal ions as well as fluoride‐induced optical changes respectively . In free probe, the dihedral angle between two pyridine rings of bipyridine unit was found to be ∼30°, whereas, in presence of Zn 2+ it became 0.5°.…”

A new highly selective “off–on” typical chemosensor of Al3+, 1-((Z)-((E)-(3,5-dichloro-2-hydroxybenzylidene)hydrazono)methyl) naphthalene-2-ol, an experimental and in silico study

“…DFT and TD-DFT calculations 32 were performed on a PC with Processor Intel®Xeon (R) CPU E5-2650 v2@2.60 GHz × 32, RAM 16 GB, Hard disk SSD PCIe, and VGA Zotac GeForce GTX 1080TI AMP EXT CORE. The calculation was performed using the Gaussian 09 program 34 with B3LYP hybrid method 35 and a basis set of 6-311+G(d,p). To achieve the actual condition of experiments, the solvent effect of DMSO was included in the calculations employing Integral Equation Formalism Variant Polarizable Continuum Mode (IEFPCM).…”

“… 36 Calculation covered such parameters as, structural geometry and spectrum of infra-red, for the mechanism of interaction study, 36 and gap energy of HOMO–LUMO to study the stability of the chelate compound. 35 …”