A spectrophotometric determination and the quantum chemical investigation of Pd(II)-3-hydroxy-2-(4-methoxyphenyl)-4-oxo-4H-1-benzopyran complex

An analytical approach has been instigated for spectrophotometric inquisition of trace amounts of palladium in its bivalent oxidation state employing a novel 1-benzopyran derivative viz. A 1:2 [Pd(II):HMPB] light yellow complex is formed by a spontaneous interaction between Pd(II) and HMPB. The complex is quantitatively extracted from a weakly basic medium into dichloromethane absorbing prevalently and consistently at 405-425 nm. The method coheres to linearity up to 1.5 µg mL-1 of palladium(II). Analytical parameters such as the molar absorption coefficient (ε=3.011 × 104 L mol-1 cm-1), Sandell's sensitivity [0.0035 µg Pd(II) cm-2], % RSD (0.62%) and the limit of detection [0.0147 µg Pd(II) mL-1] indicate that the study satisfies all the criteria for good sensitivity, precision and accuracy. In addition, intervention with regard to numerous anions/complexing agents and cations of primary analytical importance has been performed to assess the method's flexibility and usefulness. The results show that the majority of them do not cause any interference during determination. To better understand chemistry of the prepared complex, spectroscopic quantum chemical studies including DFT and MEP mapping based on examination of the electronic characteristics of the complex in its most stable least energy conformation are used. KEY WORDS: Palladium, 3-Hydroxy-2-(4-methoxyphenyl)-4-oxo-4H-1-benzopyran, Extractive spectrophotometric determination, DFT, MEP, Docking Bull. Chem. Soc. Ethiop. 2024, 38(3), 591-603.                                                               DOI: https://dx.doi.org/10.4314/bcse.v38i3.4