Computational Insights in the Spectrophotometrically Analyzed Niobium (V)- 3-Hydroxy-2-(4-methylphenyl)-4H-chromen-4-one Complex using DFT Method

Using 3-hydroxy-2-(4-methylphenyl)-4H-chromen-4-one (HMC) as a complexing agent in an acidic medium, a simple, quick, highly sensitive, and selective approach for the extractive spectrophotometric measurement of micro quantities of niobium (V) is developed. The yellowish 1:3 complex can be extracted 100 % in dichloromethane (DCM), attaining maximum absorbance in the wavelength range 388-407 nm. At 400 nm, the selected wavelength, the approach follows a linear calibration curve up to 2.2 g Nb (V) ml-1 and 0.395-1.78 ppm Nb (V) as identified from the Ringbom Plot with molar absorptivity, specific absorptivity, and Sandell's sensitivity of 4.926 × 104 l mol-1 cm-1, 0.5302 ml g-1 cm-1 and 0.0019 µg Nb cm-2, respectively. With a correlation coefficient of 0.9994, the linear regression equation is Y = 0.514 X + 0.016. The method's detection limit is 0.0698 µg ml-1. The presented determination of pentavalent niobium is unaffected by 33 cations and 22 anions/complexing agents. The approach has good reproducibility and can be used to determine niobium in a satisfactory manner. The analytical study has been correlated well with the theoretical approach of Density Functional Theory (DFT) for quantum chemical calculations. DFT effectively helped determine and interpret the chemical behavior of the obtained Nb(V)-HMC complex, explaining its stability and reactivity pattern.