Degradation Mechanisms of 4,7-Dihydroxycoumarin Derivatives in Advanced Oxidation Processes: Experimental and Kinetic DFT Study

Abstract

Coumarins represent a broad class of compounds with pronounced pharmacological properties and therapeutic potential. The pursuit of the commercialization of these compounds requires the establishment of controlled and highly efficient degradation processes, such as advanced oxidation processes (AOPs). Application of this methodology necessitates a comprehensive understanding of the degradation mechanisms of these compounds. For this reason, possible reaction routes between HO• and recently synthesized aminophenol 4,7-dihydroxycoumarin derivatives, as model systems, were examined using electron paramagnetic resonance (EPR) spectroscopy and a quantum mechanical approach (a QM-ORSA methodology) based on density functional theory (DFT). The EPR results indicated that all compounds had significantly reduced amounts of HO• radicals present in the reaction system under physiological conditions. The kinetic DFT study showed that all investigated compounds reacted with HO• via HAT/PCET and SPLET mechanisms. The estimated overall rate constants (koverall) correlated with the EPR results satisfactorily. Unlike HO• radicals, the newly formed radicals did not show (or showed negligible) activity towards biomolecule models representing biological targets. Inactivation of the formed radical species through the synergistic action of O2/NOx or the subsequent reaction with HO• was thermodynamically favored. The ecotoxicity assessment of the starting compounds and oxidation products, formed in multistage reactions with O2/NOx and HO•, indicated that the formed products showed lower acute and chronic toxicity effects on aquatic organisms than the starting compounds, which is a prerequisite for the application of AOPs procedures in the degradation of compounds.

Influence of acid–base equilibrium on interactions of some monofunctional coumarin Pd(ii) complexes with biologically relevant nucleophiles-comprehensive kinetic study

“…33 Numerous research studies have provided information supporting the justification for using the protocol, demonstrating a strong correlation with experimental measurement results. [38][39][40][41] Due to these reasons, we believe that the utilized methodology in this study will significantly contribute to precisely elucidating the mechanisms for various inorganic reactions. Quantitative (effective rate constant, k eff ) and qualitative parameters of investigation reaction mechanisms are obtained through a series of calculations conducted under specific reaction conditions.…”

“…45 These methods have shown their effectiveness in thermodynamic and kinetic studies of the mechanisms of various chemical reactions. [38][39][40][41][46][47][48] In addition to the theoretical method, the inclusion of an appropriate basis set is necessary for the creation of a comprehensive theoretical model. The utilization of the 6-311++G(d,p) basis set, 49 in conjunction with the def2-TZVPD, 50 LANL2TZ( f ), 51 cc-pVDZ 52 set specifically designed for metal ions, has demonstrated significant efficacy in the structural characterization of different complexes.…”

Identifying the Degradation Products of Dexamethasone for COVID‐19 Treatment in Mexico City's Wastewater: Theory and Experiments

“…[21,22] This strategy may be used in drug screening for the development of drug molecules by predicting degradation pathways, so that the risk of treatment failure can be reduced. There are limited computational studies on the degradation routes on drugs in sewage, [23][24][25] and no data is reported for dexamethasone. Therefore, the thermodynamic stabilities of possible degradation products from the decomposition of this drug can add valuable information to the current state of the knowledge.…”

Chitosan Hydrogels for Water Purification Applications

“…Several technologies have been developed for water treatment, including wastewater purification and recycling, including precipitation [ 10 , 11 ], oxidation [ 12 ], membrane filtration [ 13 , 14 , 15 ], adsorption [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ], biological treatments [ 23 , 24 , 25 ], advanced oxidation processes [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ], etc. However, some of these technologies are expensive, complex, have high energy consumption, or even low efficiency.…”

“…It was also pointed out that a growing number of chemicals threaten the aquatic environment. Once present in water, some of them manage to Several technologies have been developed for water treatment, including wastewater purification and recycling, including precipitation [10,11], oxidation [12], membrane filtration [13][14][15], adsorption [16][17][18][19][20][21][22], biological treatments [23][24][25], advanced oxidation processes [26][27][28][29][30][31][32], etc. However, some of these technologies are expensive, complex, have high energy consumption, or even low efficiency.…”