Introduction to Radical Species

The reaction mechanism, focused on active sites in the atom level and dominant radical species generated through the reaction, was analyzed by characterization, density functional theory (DFT) calculation, quenching experiments, and electron paramagnetic resonance analysis.

Investigations with electron paramagnetic resonance spectroscopy suggested that the reactivity in the early stages was mediated by surface-bound reactive oxygen species; no homogeneous radical species were observed in solution.

Photoredox catalysis offers numerous opportunities for the convenient synthesis of active organic radical species through single electron transfer (SET), which is complementary to conventional two-electron processes.

Critical to the success is the utilization of a proline-based N,N,P-ligand to enhance the reducing capability of copper, thus easily converting benzyl bromides to the corresponding radical species via a single-electron transfer process under ambient conditions.

In this research, the reactive radical species in photocatalytic activities of a composite photocatalyst made from PET filaments loaded with Ag-TiO2 nanoparticles under visible light irradiation, in comparison with those of as-modified Ag-TiO2 nanoparticles, were reported and its photocatalytic mechanism was investigated.

1,3-Dioxolane is converted to its radical species in the presence of persulfate and an iridium catalyst upon visible light irradiation, which then reacts with electron-deficient alkenes.

In particular, the scavenger tests and electron spin resonance spectra demonstrated that •O2− and •OH are the primary oxidative radical species in the photocatalytic systems and confirmed the formation of the double Z-scheme structure.

The radical species trapping and electron spin resonance (ESR) results demonstrated that ·OH was the most dominated species for MNZ oxidation, and photo-generated electrons were responsible for Cr (VI) reduction.

Thanks to their structural peculiarities, polyphenolic compounds are characterized as good scavengers of free radical species.

Overwhelming free radical species formation results in mitochondrial dysfunction, as well as cellular and metabolic imbalance, which becomes exacerbated with increasing age.

Significant enhancement in recycling of the dissolved and surface Fe(II) was confirmed which contributed to the generation of free and surface-bound active radical species (OH, O2-, 1O2, SO4-).

The Rhodamine B (RhB) dye degradation performance of the photocatalyst, its reusability, and active radical species involved in the photocatalytic reaction in all nanocomposites are obtained by analyzing UV–vis absorbance spectra.

A common and effective approach is employing the radical scavengers-based material, which can reduce the content of reactive radical species followed by the improvement of proton exchange membrane and catalyst layer stability.

Despite the vital roles of reactive radical species in the coupled iron-carbon composite/persulfate (PS) system for eliminating pollutants, nonradical contributions are typically overlooked.

In this context, persulfate-mediated processes are of relevant importance once persulfate can be activated in situ, promoting the formation of highly oxidative radical species.

In particular, the scavenger tests and electron spin resonance spectra demonstrated that •O2− and •OH are the primary oxidative radical species in the photocatalytic systems and confirmed the formation of the double Z-scheme structure.

The diffusion-controlled reaction between these two radical species generates ONOO−, as confirmed by the use of fluorescein-boronate as a highly selective chemical probe.

The CF/ABF-centred polymers showed mixed mechanochromism derived from the simultaneous generation of two radical species.

One way of removing ROS from the body is through the use of radical scavengers, which are compounds capable of giving up an electron to neutralize the ROS yet form a stable radical species themselves.

Chemical indices, especially diradical character, are utilised to examine the functions and reactivity of stable radical species.

Electrostatic interaction was suggested as a plausible mechanism for RO adsorption whereas photogenerated holes controlled photocatalytic degradation of RO by producing sufficient quantities of different radical species.

The EPR approach shows that at least two different radical species are present in both cases, contributing to the paramagnetism of the samples.

The reaction mechanism, focused on active sites in the atom level and dominant radical species generated through the reaction, was analyzed by characterization, density functional theory (DFT) calculation, quenching experiments, and electron paramagnetic resonance analysis.

Radical quenching experiments revealed •OH and SO4•− were active while SO4•− was the dominant radical species.

Sulfate radical (SO4•-) was generated during the Co-g-C3N4/PMS process, reacting with chloride ions to produce chloride radical (Cl•), which was identified as the main radical species for the transformation of ammonia to nitrogen gas.

The addition of glucose as a quencher in the initial solution showed that the •OH and SO4 radicals were the main radical species in the ZVI/PS/UV process for phenol removal.

Among these methods, the oxygen radical absorbance capacity (ORAC) assay comes close to the oxidation reaction in the living body because it generates radical species that mimic the lipid peroxyl radical involved in the peroxidation reaction of biological components and react in a phosphate buffer.

Under visible-light irradiation, DPNDI can be easily excited to generate radical species DPNDI* that could be further excited in the presence of the electron donor pyrrolidine for the inert O2 activation.

The mechanistic investigations revealed that the catalytic cycle was initiated by the oxidation of Cu (I) with NFSI to provide the nitrogen-centered radical species.

Control experiments implicate the in situ generation of a tertiary carbon-centered radical species.

The optical properties of the synthesized nanoparticles were investigated, and their reactive oxygen radical species (ROS) generation was confirmed using UV–vis spectroscopy.

Incubation of RBC with only HgCl2 increased production of nitrogen and oxygen radical species, enhanced methemoglobin levels, heme degradation, free ferrous iron, oxidation of proteins and membrane lipids and reduced antioxidant capacity of cells.

Photoredox catalysis offers numerous opportunities for the convenient synthesis of active organic radical species through single electron transfer (SET), which is complementary to conventional two-electron processes.

Most organic radical species are transient and were long considered to be beyond control.

The degradation of MB was mainly indicated by superoxide radical species as confirmed by the trapping experiment.

The degradation of MB was mainly indicated by superoxide radical species as confirmed by the trapping experiment.

In photo-assisted EAOPs the inactivation of pathogens takes place by means of mechanisms that occur at different distances from the anode, that is: (i) directly at the electrode’s surface (direct oxidation), (ii) at the anode’s vicinity by means of electrochemically generated hydroxyl radical species (quasi-direct), (iii) or at the bulk solution (away from the electrode surface) by photo-electrogenerated active species (indirect oxidation).

Electron spin resonance spectroscopy (ESR) was used to elucidate the underlying mechanism of this photocatalytic activity through the generation of hydroxyl radical species.

Copper(III) ligand radical species have also been formulated and supported by theoretical studies.

Notably, this is the first example of a plutonium-ligand radical species and a rare example of magnetic data being recorded for a homogeneous plutonium coordination complex.

The carbon radicals then add to diverse alkenes, delivering new carbon radical species, and the final products are formed with N-centered radicals via a radical-radical coupling.

The irradiation of halogen-bonded complexes with light leads to the homolysis of carbon-halogen bonds and the formation of the corresponding carbon radical species.

Theoretical calculations indicated that large spin densities at the reaction positions of the bis(cation radical) and/or cation radical species are needed for the C-C bond formation.

Density functional theory studies on the electronic properties of the active species of the system, namely the iron(IV)-oxo with equatorial ligand cation radical species and its reactivity in oxygen atom transfer were studied.

The ratio of these two hyperfine couplings is reversed in the oxidized and the reduced radical species.

The ratio of these two hyperfine couplings is reversed in the oxidized and the reduced radical species.

In a further photoredox-catalyzed hydroarylation protocol, the coupling of functionalized, electronically unbiased olefins is achieved under air and within minutes of blue light irradiation through the intermediacy of reactive (hetero)aryl radical species with full retention of the DNA tag integrity.

These conditions employ a strongly reducing organic photoredox catalyst in combination with a trialkylamine reductant to achieve formation of aryl radical species.

Critical to the success is the utilization of a proline-based N,N,P-ligand to enhance the reducing capability of copper, thus easily converting benzyl bromides to the corresponding radical species via a single-electron transfer process under ambient conditions.

Laser flash photolysis studies indicate that PET from SCX6 to LC is followed by proton abstraction by LC from the host or from the medium, to generate the corresponding radical species.

These potential photoproducts could include deprotonated neutral radical species, deprotonated anion species, radical cations and radical anions.

Their precursors may be the fragment neutral radical species generated from TNT exposed in the m-DBD plasma.

An overview of all currently known structures containing the 1,2,5-thiadiazole 1,1-dioxide motif (including the anions radical species) is provided according to the Cambridge Structural Database search.

The monolithic photocatalyst ensures easy transport of pollutants to the photoactive sites, thereby ensuring ≥99% dye degradation, through superoxide anion radical species.

In our studies, various radical species such as alkene and arene radical cations and carbon‐ and heteroatom‐centered radicals are generated from readily available precursors through direct electrolysis, molecular electrocatalysis or molecular electrophotocatalysis.

In this system, the results of Electron paramagnetic resonance analysis (EPR) and scavenger experiment suggested that PFOA degradation was a co-dependent mechanism via photogenerated electrons, photogenerated holes (h+) and various radical species, rather than a single active constituent.

In this regard, acetylenic sulfones can directly react with diverse alkyl radical species for the preparation of synthetically useful internal alkynes.

Extensive mechanistic studies on this transformation have elucidated that a unified single electron transfer mechanism is in operation for the activation of alkyl halides to the corresponding alkyl radical species which then engages in subsequent coupling with aryl halides through a reductive elimination pathway (Scheme 1B).

The reaction mechanism, focused on active sites in the atom level and dominant radical species generated through the reaction, was analyzed by characterization, density functional theory (DFT) calculation, quenching experiments, and electron paramagnetic resonance analysis.

The radical species generated via UV irradiation can chemically initiate the photoinitiators, which are then polymerized and deposited on inorganic nanoparticles via heterogeneous nucleation, forming a soft oligomer coating smaller than 40 nm.

The radical species trapping and electron spin resonance (ESR) results demonstrated that ·OH was the most dominated species for MNZ oxidation, and photo-generated electrons were responsible for Cr (VI) reduction.

Additionally, radical species trapping was applied to more deeply study the charge carrier transfer behavior of the samples.

The Rhodamine B (RhB) dye degradation performance of the photocatalyst, its reusability, and active radical species involved in the photocatalytic reaction in all nanocomposites are obtained by analyzing UV–vis absorbance spectra.

An extended analysis of spectra of air and helium discharges mixed with water and hexamethyldisiloxane vapors was performed, with the identification of active radical species involved in the surface functionalization of polymeric nanoparticles.

Critical to the success is the utilization of a proline-based N,N,P-ligand to enhance the reducing capability of copper, thus easily converting benzyl bromides to the corresponding radical species via a single-electron transfer process under ambient conditions.

The essential process is the generation of a radical species via single electron transfer (SET) between the substrate and catalyst.

In combustion engines, radical species undergo isomerization reactions that allow fast addition of O 2.

Radical species undergo chemical reactions, such as oxidation or nitration reaction and form products on the electrode surfaces.

Therefore, the results obtained experimentally suggest that the reaction takes place via an ionic route while radical species would play a minor role.

Alkoxy radical species would be key intermediates in the present transformation, which generate through homolysis of the O-Br bond in hypobromite intermediates under visible light irradiation.

To identify radical species responsible for the oxidation process, selective radical scavenging experiments were performed and a purposed oxidation mechanism was discussed.

Moreover, acetylperoxyl radical (CH3CO3 ) was identified as the primary radical species responsible for organic micropollutants degradation, exhibiting high selectivity towards contaminants containing electron-rich groups.

Given this, detection and quantification of radical species produced during photocatalysis have become an area of increasing interest.

RESULTS While Ag or g-C3N4 moderately affected microbial metabolism according to the mean of the altered metabolites, multiple cell systems contributing to rapid cell death were immediately affected by the light-triggered radical species produced when Ag and g-C3N4 were as xAg/g-C3N4.

Ignition occurs initially with relatively lean mixtures, and compared to the corresponding homogeneous stagnant adiabatic combustion, the loss of radical species associated with flow transportation causes a delay in ignition.

In the presence of elevated manganese, there is an increased generation of reactive radical species associated with dysfunction of the major terminal oxidase, the cytochrome aa3 heme‐copper menaquinol oxidase (QoxABCD).