The Mechanism and Kinetics of Hydroxyl Radical Polymerization of Nonionized Acrylic Acid and Its Derivatives in Aqueous Solution.

In the free-radical polymerization of acrylic acid derivatives (), including acrylic acid (), methyl acrylate (), acrylamide (), methacrylic acid (), and methyl methacrylate (), initiation and propagation occur via radical addition to . Although extensive experimental data exist about this industrial process, many mechanistic aspects of the reactions themselves remain unclear, largely because of the challenge that the characterization of reaction mechanisms poses to experimental methodology. Computational methods offer an alternative avenue to deliver fast and accurate results on the mechanistic details, as evidenced by various theoretical studies in the literature.

A mercury complex-based fluorescent sensor for biological thiols.

A novel fluorescent sensor, Hg(DST), was developed for the selective detection of biological thiols, including glutathione (GSH), cysteine (Cys), and homocysteine (Hcy), in fully aqueous solutions at pH 7.2. The sensor exhibited significant fluorescence quenching upon coordination with Hg, which was reversibly restored in the presence of thiols due to the formation of thermodynamically favored Hg-thiol complexes.

The reaction of acetamiprid with OH radicals in the environment: a theoretical study.

The chemical fate of acetamiprid (AMP), a neonicotinoid pesticide, is determined by photo-oxidation: a combination of radical degradation pathways driven by the action of hydroxyl radicals. This study utilizes quantum chemical calculations to investigate the reaction of AMP with hydroxyl radicals in atmospheric, lipidic, and aqueous media. It was shown that the degradation process has a steep temperature dependence with the overall rate constant decreasing from 9.

Theoretical study on the influence of OH group position on the free radical scavenging ability of tryptamine derivatives.

A density functional theory (DFT) study investigated the influence of hydroxyl (OH) groups on the free radical scavenging capacity of tryptamine derivatives (OH-TAs). Stable forms of OH-TAs were evaluated in both gaseous and aqueous environments. While neutral forms predominate in the gas phase, cationic forms (protonated at the NH group) are favored in aqueous solution.

Carboxymethylnaringenin: a promising antioxidant in the aqueous physiological environment.

The synthetic naringenin derivative (2S)-8-carboxymethylnaringenin () was developed for the treatment of bacterial and viral respiratory infections. There are indications that may act as an antioxidant, however, no studies have been conducted in this regard. This work is aimed at assessing the antiradical capacity of against various physiologically relevant species in physiological environments by using thermodynamic and kinetic calculations.

The radical scavenging activity of 1-methyl-1,4-dihydronicotinamide: theoretical insights into the mechanism, kinetics and solvent effects.

1,4-Dihydronicotinamide derivatives, including 1-methyl-1,4-dihydronicotinamide (MNAH), are derivatives of the active center of nicotinamide coenzyme (NADH) and are therefore potent radical scavengers. MNAH serves as a useful model of NADH that allows for modeling studies to address the activity of this important biomolecule. In this work, MNAH activity was evaluated against typical free radicals using quantum chemical calculations in physiological environments, with a secondary aim of comparing activity against two physiologically relevant radicals of markedly different stability, HO˙, and HOO˙, to establish which of these is a better model for assessing antioxidant capacity in physiological environments.

Reactions of Diphenylamine with OH Radicals in the Environment: Theoretical Insights into the Mechanism, Kinetics, Temperature, and pH Effects.

Diphenylamine () has been widely utilized in industrial chemicals, but its degradation by HO radicals in the environment has not been fully studied yet. The present study uses quantum chemical calculations to evaluate the reaction of with HO radicals in atmospheric and aqueous environments. The results showed that, in the atmosphere, the diphenylamine reacted with the HO radical rapidly, with an overall rate constant of 9.

A Novel Fluorescent Sensor for Detecting Ag and Hg ions: A Combination of Theoretical and Experimental Studies.

A new fluorescent sensor based on diethylaminosalicylaldehyde-thiosemicarbazide (DST) was studied using a combination of density functional theory calculations and experimental investigations. DST was able to detect the metal ions Ag and Hg in the presence of various competing metal ions and anions, with detection limits of 0.45 and 0.

Synthesis and computational evaluation of the antioxidant activity of pyrrolo[2,3-]quinoxaline derivatives.

Pyrrolo[2,3-]quinoxaline derivatives are known to possess antioxidant, anticancer, and antibacterial properties. Here we report the successful synthesis of five derivatives of 3-hydroxy-3-pyrroline-2-one through substitution. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was employed to evaluate the antioxidant activity of the compounds.

Computational assessment of the radical scavenging activity of cleomiscosin.

Coumarinolignans such as cleomiscosin A (CMA), cleomiscosin B (CMB), and cleomiscosin C (CMC) are secondary metabolites that were isolated from diverse plant species. Cleomiscosins (CMs) have numerous interesting biological activities, including noteworthy cytotoxicity of cancer cell lines along with hepatoprotective and assumed antioxidant activities. In this present study, the antioxidant properties of three cleomiscosins were investigated with a focus on the structure-activity relationship using thermodynamic and kinetic calculations with the M06-2X/6-311++G(d,p) method.

The radical scavenging activity of monocaffeoylquinic acids: the role of neighboring hydroxyl groups and pH levels.

Caffeoylquinic acids (CQAs) are well-known antioxidants. However, a key aspect of their radical scavenging activity - the mechanism of action - has not been addressed in detail thus far. Here we report on a computational study of the mechanism of activity of CQAs in scavenging hydroperoxyl radicals.

The Theoretical and Experimental Insights into the Radical Scavenging Activity of Rubiadin.

Rubiadin (), an anthraquinone derivative, is obtained from , a plant species classified under the Rubiaceae family. Rubiadin has proven beneficial properties, such as anticancer, neuroprotective, anti-inflammatory, and antidiabetic activity. The antioxidant activity of this molecule was suggested by some experimental results but has not been clearly established thus far.

A Comprehensive Study of the Radical Scavenging Activity of Rosmarinic Acid.

Rosmarinic acid () is reported in separate studies to be either an inducer or reliever of oxidative stress, and this contradiction has not been resolved. In this study, we present a comprehensive examination of the radical scavenging activity of using density functional theory calculations in comparison with experimental data. In model physiological media, exhibited strong HO radical scavenging activity with overall rate constant values of 2.

Antiradical Activity of Lignans from : Theoretical Insights into the Mechanism, Kinetics, and Solvent Effects.

Sumatranus lignans () isolated from have demonstrated bioactivities, e.g., they were shown to exhibit immunosuppressive properties in previous research.

Study of the Mechanism and Kinetics of the Radical Scavenging Activity of 2-Mercaptoimidazole.

2-Mercaptoimidazole () is related to natural ovothiols that are recognized as powerful radical scavengers. Yet, despite early reports of its potent antioxidant properties, received little attention. Specifically, its radical scavenging activity against typical free radicals like HO and HOO has not yet been studied in terms of its mechanism and kinetics.

Feruloylmonotropeins: promising natural antioxidants in .

is a widely used medicinal herb in Vietnam, China, India, and Japan for the treatment of a variety of conditions, including toothache, chest pains, piles, and spleen inflammation. There is broad interest in identifying the composition of its extracts and confirming their numerous biological activities, including anti-nociceptive, antiviral, and anticancer properties. Two iridoid glucosides obtained from the MeOH extract of , 6'-O--feruloylmonotropein (6-FMT) and 10'-O--feruloylmonotropein (10-FMT), are potential antioxidants based on their structure.

Reactions of nicotine and the hydroxyl radical in the environment: Theoretical insights into the mechanism, kinetics and products.

Nicotine (NCT) is a prevalent and highly poisonous tobacco alkaloid found in wastewater discharge. Advanced oxidative processes (AOP) are radical interactions between harmful pollutants and ambient free radicals that, theoretically, result in less toxic compounds. For a better understanding of the chemical transformations and long-term environmental effects of toxic discharges, the study of these processes is crucial.

Large-Scale Synthesis of Nanosilica from Silica Sand for Plant Stimulant Applications.

Nanosilica is a versatile nanomaterial suitable as, e.g., drug carriers in medicine, fillers in polymers, and fertilizer/pesticide carriers and potentially a bioavailable source of silicon in agriculture.

Synthesis and evaluation of the antioxidant activity of 3-pyrroline-2-ones: experimental and theoretical insights.

The heterocyclic γ-lactam ring 2-pyrrolidinone has four carbon atoms and one nitrogen atom. Among the group of derivatives of 2-pyrrolidinones, 1,5-dihydro-2-pyrrol-2-ones, also known as 3-pyrroline-2-ones, play a significant structural role in a variety of bioactive natural compounds. In this study, three-component reactions were used to successfully synthesize six polysubstituted 3-hydroxy-3-pyrroline-2-one derivatives.

A Potent Antioxidant Sesquiterpene, Abelsaginol, from : Experimental and Theoretical Insights.

The sesquiterpenoid compound abelsaginol () was successfully isolated from for the first time. The compound was identified using NMR and MS data. The antioxidant activity of was also evaluated both theoretically and experimentally.

7-O-Galloyltricetifavan: a promising natural radical scavenger.

7-O-Galloyltricetifavan (), a natural flavonoid, is isolated from the leaves of . The compound exhibits a variety of biological activities. This study details the evaluation of the HOO antiradical activity of by quantum chemistry calculations.

The hydroperoxyl radical scavenging activity of natural hydroxybenzoic acids in oil and aqueous environments: Insights into the mechanism and kinetics.

Foods that contain hydroxybenzoic acid derivatives (HBA) include red fruits, black radish, onion, and potato peel. HBA are widely known for their anti-inflammatory, anti-cancer, and especially antioxidant capabilities; however, a comprehensive study of the mechanism and kinetics of the antiradical action of these compounds has not been performed. Here, we report a study on the mechanisms and kinetics of hydroperoxyl radical scavenging activity of HBA by density functional theory (DFT) calculations.