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Hydrogen peroxide and peroxymonocarbonate anion-based bleach reactions are important for many applications such as paper bleach, waste water treatment and laundry. Nonheme iron(III) complexes, $[\mathrm{Fe}^{\mathrm{III}}(\mathrm{L}^{1-4})\mathrm{Cl}_{2}]$ with the 1,3-bis($2^{\prime}$-Ar-imino)isoindolines ligands ($\mathrm{HL}^{n}$, $n=$1–4, Ar $=$ pyridyl, thiazolyl, benzimidazolyl and N-methylbenzimidazolyl, respectively) have been shown to catalyze the oxidative degradation of morin as a soluble model of a bleachable stain by $\mathrm{H}_{2}\mathrm{O}_{2}$ in buffered aqueous solution. In these experiments the bleaching activity of the catalysts was significantly influenced by the Lewis acidity and redox properties of the metal centers, and showed a linear correlation with the $\mathrm{Fe}^{\mathrm{III}}/\mathrm{Fe}^{\mathrm{II}}$ redox potentials (in the range of 197–415 mV) controlled by the modification of the electron donor properties of the ligand introducing various aryl groups on the bis-iminoisoindoline moiety. A similar trend but with low yields was observed for the disproportionation of $\mathrm{H}_{2}\mathrm{O}_{2}$ (catalase-like reaction) which is a major side reaction of catalytic bleach with transition metal complexes. The effect of bicarbonate ions might be explained by the reduction of Fe(III) ions and/or the formation of peroxymonocarbonate monoanion, which is a much stronger oxidant and could increase the formation of the catalytically active high-valent oxoiron species.

Tridentate 1,3-bis($2^{\prime}$-Ar-imino)isoindolinato manganese(II) complexes were found to efficiently catalyze the mild oxidation of organic sulfides to sulfoxides and benzyl alcohols to benzaldehydes with mCPBA and PhIO, but they proved almost ineffective by the use of $t$BuOOH and H2O2 at room temperature. The effect of electron-withdrawing and electron-donating substituents on the substrates (thioanisole and benzylalcohol), and the redox properties of the metal center by varying the aryl groups on the bis-iminoisoindoline were investigated, and showed a significant impact on the catalytic C–H oxidation and sulfoxidation reactions. Based on these results, including the linear correlations between the oxidation reactivity of the catalysts and $\mathrm{Mn}^{\mathrm{III}}/\mathrm{Mn}^{\mathrm{II}}$ redox potentials, the Hammett correlation with $\rho = -0.27$ for 4R-PhSMe and $\rho = -0.27$ for 4R-PhCH2OH, electrophilic oxomanganese(IV) intermediate has been suggested as key oxidant. Furthermore, the small negative slope $({-}0.5)$ from the $\log k_{\mathrm{rel}}$ versus $E^{\mathrm{o}}_{\mathrm{ox}}$ for 4R-PhSMe gives clear evidence for the direct oxygen atom transfer (OAT) mechanism instead of electron transfer (ET) mechanism between the $\mathrm{Mn}^{\mathrm{IV}}\mathrm{O}$ and PhSMe.

The application of hurdle approach using high hydrostatic processing (HHP) with bioactive compounds (BACs) to preserve meat quality is promising due to safety, improved well-being, and easier acceptance by customers compared to the use of synthetic preservatives. This study was designed to investigate the influence of natural phenolic BAC carvacrol (CARV) at 500 and 1000 ppm combined with HHP (300 and 600 MPa) on the quality attributes of chicken meat after being vacuum-sealed and kept at 4 ± 0.5 °C for 28 days. The HHP showed a significantly higher pH rate (P<0.05), increased L* and b* value, decreased a* values, and reduction in water holding capacity (WHC) compared to unpressurized control meat with/without CARV. Reduction in thiobarbituric acid reactive substances (TBARS) indexes was perceived in meat supplemented with CARV, and low level of HHP (300 HHP) whereas significantly increased lipid oxidation was witnessed with HHP 600 MPa. At day 28, an increase in aerobic mesophilic counts (AMCs) was observed in all meat samples. However, reductions of about 0.6, 0.8, and 1.1 log in AMCs were seen in meat treated with 600HHP-No CARV, HHP300-CARV 500 ppm, and 600HHP-CARV 1000 ppm, respectively. Furthermore, despite the overlapping aroma pattern between meat containing CARV and control groups, the electronic nose was able to discriminate control from samples subjected to HHP. The current results demonstrate that the addition of CARV improved the conservation effects of HHP with less oxidative deterioration of fresh chicken meat during chilling storage. [ABSTRACT FROM AUTHOR]

Investigations of the chemical composition of kidney stones are essential for understanding of the nature formation of stones and for the development of preventative treatment methods. Instrumental activation analysis radiations are significant tools for determining the composition of kidney stones. Kidney stones of varying compositions were investigated through the use of X-ray powder diffraction (XRD) and X-ray fluorescence (XRF) techniques. Materials can be observed in two very different ways due to the X-ray photon's unique interaction with matter. Using a combination of X-ray fluorescence and activation analysis, this method provides a thorough assessment of kidney stones. The XRF, FTIR, and XRD methods were used to two groups of kidney stones. Based on the XRF analysis, the elements Ca, S, P, Si, and Cl were determined to have the highest concentrations. The heavy metals Cu, Fe, Zn, Ta, Sn, and Pb, were detected as trace elements by XRF. The purpose of this study was to use XRF, XRD, and FTIR instrumental activation analysis techniques to determine the chemical composition of kidney stones. [ABSTRACT FROM AUTHOR]

Non-heme manganese(II) complexes [(IndH)MnIICl2] (1) and [(N4Py*)MnII(CH3CN)](ClO4)2 (2) with tridentate isoindoline and pentadentate polypyridyl ligands (IndH = 1,3-bis(2′-pyridylimino)isoindoline; N4Py* = N,N-bis(2-pyridylmethyl)-1,2- di(2-pyridyl)ethylamine) proved to be suitable to catalyze the oxidative demethylation of N,N-dimethylaniline (DMA) with various oxidants such as tert-butyl hydroperoxide (TBHP), peracetic acid (PAA), and meta-chloroperoxybenzoic acid (mCPBA), resulting N-methylaniline (MA) as a main product with N-methylformanilide (MFA) as a result of a free-radical chain process under air. The effect of electron-donating and electron-withdrawing substituents on the aromatic ring on the relative reactivity of the substrates and on the product composition (MA/MFA) was also studied and showed a significant impact on the catalytic N-demethylation reaction. Based on the Hammett correlation with ρ = −0.38 (PAA), −0.45 (mCPBA), and −0.63 (TBHP) for 1 and ρ = −0.38 (PAA) and −0.37 (mCPBA) for 2, an electrophilic intermediate is suggested as the key oxidant. Furthermore, the spectral investigation (UV-Vis) resulted in direct evidence for the formation of a high-valent oxomanganese(IV) and a transient radical cation intermediate, p-Me-DMA•+, suggesting that the initial step in the manganese-catalyzed oxidations is a fast electron-transfer between the amine and the high valent oxometal species. The mechanisms of the subsequent steps are discussed. [ABSTRACT FROM AUTHOR]

The synthesis of a number of pentaborate(1-) salts from cations arising from N-substituted α,α-, α,β-, and α,γ-diaminoalkanes has been attempted in aqueous solution from B(OH)3 and the appropriate diammine in a 10:1 ratio. Despite relatively mild work-up conditions the pentaborate(1-) salts prepared were not always as anticipated and the following compounds were isolated in good yield: [Me2NH(CH2)2NHMe2][B5O6(OH)4]2 (1), [Et2NH(CH2)2NHEt2][B5O6(OH)4]2 (2), [Et2NH2][B5O6(OH)4] (3), [Me2NH2][B5O6(OH)4] (4), [Me2NH(CH2)3NHMe2][B5O6(OH)4]2 (5), [Et2NH(CH2)3NHEt2][B5O6(OH)4]2 (6), [Me3NCH2CH=CH2][B5O6(OH)4] (7), and [Me3N(CH2)3NMe3] [B5O6(OH)4]2.0.5H2O (8). The tetraborate(2-) salt, [Me3N(CH2)2NMe3][B4O5(OH)4].2B(OH)3.2H2O (9) was obtained in moderate yield (41%) from a 3:1 reaction of B(OH)3 with [Me3N(CH2)2NMe3](OH)2. All compounds were characterized by spectroscopy (1H, 11B, 13C NMR and IR) and thermal gravimetric analysis (TGA). BET analysis on materials derived thermally from selected samples (1, 2, 6, 7) all had porosities of < 1 m2/g, demonstrating that they were non-porous. Single-crystal XRD structures were obtained for 2, 3, 7, 8 and 9 and all contain extensive H-bonded polyborate lattices. [ABSTRACT FROM AUTHOR]