The coordination ability of the (ppy)Au(IPr)
fragment ppy = 2-phenylpyridine, IPr = 1,3-
(2,6-di-isopropylphenyl)-imidazol-2-ylidene towards different anionic and neutral X ligands (X = Cl
, BF
, OTf
..., H
O, 2-butyne, 3-hexyne) commonly involved in the crucial pre-equilibrium step of the alkyne hydration reaction is computationally investigated to shed light on unexpected experimental observations on its catalytic activity. Experiment reveals that BF
and OTf
have very similar coordination ability towards (ppy)Au(IPr)
and slightly less than water, whereas the alkyne complex could not be observed in solution at least at the NMR sensitivity. Due to the steric hindrance/dispersion interaction balance between X and IPr, the (ppy)Au(IPr)
fragment is computationally found to be much less selective than a model (ppy)Au(NHC)
(NHC = 1,3-dimethylimidazol-2-ylidene) fragment towards the different ligands, in particular OTf
and BF
, in agreement with experiment. Effect of the ancillary ligand substitution demonstrates that the coordination ability of Au(III) is quantitatively strongly affected by the nature of the ligands (even more than the net charge of the complex) and that all the investigated gold fragments coordinate to alkynes more strongly than H
O. Remarkably, a stabilization of the water-coordinating species with respect to the alkyne-coordinating one can only be achieved within a microsolvation model, which reconciles theory with experiment. All the results reported here suggest that both the Au(III) fragment coordination ability and its proper computational modelling in the experimental conditions are fundamental issues for the design of efficient catalysts.
Metabolomics provides a description of the phenotype of an organism and complementary biochemical information to genomics and proteomics. The purpose of this research was to depict the metabolite ...profile of faecal samples from dogs fed three different diets through NMR spectroscopy analysis. Samples were collected from 14 dogs fed a commercial extruded diet, 18 dogs fed a homemade diet and 16 dogs fed a raw meat-based diet. The average BCS for all dogs was 4–5 and the average Faecal Score was 2–3. Only healthy animals were considered, as assessed from the clinical evaluation of the veterinarians. Faecal samples were prepared using phosphate buffer (pH 7.1) combined with deuterated water and analysed with NMR spectroscopy using a Bruker Avance III HD 400 MHz spectrometer. Principal component analysis of the spectra signals demonstrated clustering of dogs according to diet, with 57.8% of the variance explained by the first three components. Targeted metabolome analysis was also performed on 56 metabolites of interest, selected from a database of 558 metabolites. Our data suggest that metabolome analysis using NMR is a promising approach to describe the phenotypic variation that occurs among dogs fed different diets.The metabolomic approach is becoming always more important in the evaluation of the functional responses of animals to dietary intervention.NMR-metabolomics has emerged as a non-destructive technique that allows a simpler data interpretation compared to other techniques.NMR metabolome analysis resulted to be a promising approach to describe the phenotypic variation that occurs among dogs fed different diets.
This study aimed to investigate the application of isothermal calorimetry as technique for monitoring microparticles oxidation produced by particles from gas saturation solution (PGSS) technique. ...Microparticles were obtained by mixing linseed oil (9.1 g/100 g) with glycerol stearate (90.9 g/100 g). The process was carried out at 10 MPa, 55 °C for 30 min. To enhance microparticles oxidative stability, β-carotene was also added to the formulation (0.4 up to 1.6 mg/g of oil). The results showed that the fatty acid profile of the oil did not change after the encapsulation process. From the isothermal calorimetry traces, it was possible to determine the induction time (τIC) and the rates of oxidation during the inhibited (Rinh) and uninhibited (Runi) period. The microencapsulation by PGSS significantly (p < 0.05) increased τIC values of microparticles compared to the bulk oil, which resulted equal to 32 ± 1 × 104 s and 10.2 ± 2 × 104 s, respectively. On the other side, Rinh significantly decreased confirming the higher microparticles oxidative stability. β-carotene addition enhanced the oxidative stability proportionally to the concentration of the added antioxidant. At the end of the oxidation, the 3-OH-beta-apo-11-carotenal and the 3-OH-beta-apo-carotenone compounds derived from β-carotene degradation were detected.
•Isothermal calorimetry monitored microcapsules rich in unsaturated fatty acids.•The kinetics parameters were evaluated from the calorimetric traces.•β-carotene addition improved microcapsules oxidative stability.
Also in neoteric solvents!!! An efficient Cycloisomerization of N-propargylcarboxamide in green solvents has been developed and the effect of the solvent and counterion (X−) in L-Au-X catalyst has ...been rationalized.
Display omitted
For the first time, NHC-Au-X NHC = (1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene, X− = BF4−, OTf−, OTs−, TFA− catalysts were tested in the cycloisomerization of N-(prop-2-yn-yl)benzamide to 2-phenyl-5-vinylidene-2-oxazoline in a wide set of green solvents. We found that most of these solvents (cyclohexanone, isopropyl acetate, MIBK, ethyl lactate, furfuryl alcohol, γ-valerolactone, propylene carbonate and propionic acid) are comparable or better solvents with respect to traditional VOS. Furthermore, the catalyst activity is related to the basic strength of the anion and the performances of the catalysts decrease gradually with increasing basicity and hydrogen-bond acceptor power of X−. Kinetic experiments and DFT calculations seem to indicate that both the characteristic of the solvent and counterion should be taken into account.
Selective oxidation of alcohols to aldehydes or ketones is a fundamental process in organic chemistry and the development of green and sustainable transformations are strongly required. Herein, we ...focused on the development of Ru-based catalysts deposited over ceria-zirconia supports (CZRu) for the solvent free oxidation of benzyl alcohol using air as oxidant, which is a cheap and safe process and meets to the atom economy and environment requirements. XPS characterization of the material reveals that the formation of RuO2 on the surface is necessary to achieve higher catalytic activity. The activity is strongly related to the reducibility of the material and to the close interaction between ceria-zirconia and RuO2, with the likely formation of Ru-O-Ce arrangements. The greater mobility of oxygen due to the formation of bridging oxygens in Ru-O-Ce and to the formation of superoxide species (O2−) over Ce3+ sites, significantly boosts the selective oxidation of alcohols. CZRu is a promising material with a remarkable 61% alcohol conversion at 90 °C without solvents; it also exhibits high activity (55% conversion) and complete selectivity (100%) for the selective oxidation of 1-phenylethanol to acetophenone. Overall, the formulation is among the most active reported so far under solvent free conditions and molecular oxygen. In addition, the reaction over CZRu exhibits an environmental factor (E-factor) lower than 1 (0.95) confirming the sustainability of the proposed process.
Display omitted
Abstract The properties of gelatin and collagen extracted from fishery wastes, specifically from mullet ( Mugil Cephalus ) scales, are modified with the aim to achieve biocompatible films with ...tunable characteristics to design sustainable UV protection solutions in the healthcare sector. Different additives are used to the scope including plasticizers, cross‐linkers, surfactants and optical modifiers. Carbon dots (CDs) obtained from seabass ( Dicentrarchus labrax ) scales combined with polysorbate‐20 (PS) as a dispersant agent, enable the fabrication of materials capable of blocking UV radiation almost completely, a crucial feature for dermal contact applications. The addition of hydrophobic surfactants and crosslinkers as citric acid, chitosan and surface deacetylated chitin nanocrystals (CsNCs) allowed to modulate the water adsorption of the films in the range 3–30% and to reach a twofold and 4.5‐fold increase of tensile strength and elastic modulus, respectively, as compared to the neat gelatin film. Moreover, film thickness is shown to be another adjustable parameter to enhance optic, mechanical, and permeation properties: the higher the thickness, the greater the UV‐blocking properties, elongation‐at‐break and water vapor permeability, leading to films with attractive characteristics as wearable patches.
Metabolomics provides a description of the phenotype of an organism and complementary biochemical information to genomics and proteomics. The purpose of this research was to depict the metabolite ...profile of faecal samples from dogs fed three different diets through NMR spectroscopy analysis. Samples were collected from 14 dogs fed a commercial extruded diet, 18 dogs fed a homemade diet and 16 dogs fed a raw meat-based diet. The average BCS for all dogs was 4-5 and the average Faecal Score was 2-3. Only healthy animals were considered, as assessed from the clinical evaluation of the veterinarians. Faecal samples were prepared using phosphate buffer (pH 7.1) combined with deuterated water and analysed with NMR spectroscopy using a Bruker Avance III HD 400 MHz spectrometer. Principal component analysis of the spectra signals demonstrated clustering of dogs according to diet, with 57.8% of the variance explained by the first three components. Targeted metabolome analysis was also performed on 56 metabolites of interest, selected from a database of 558 metabolites. Our data suggest that metabolome analysis using NMR is a promising approach to describe the phenotypic variation that occurs among dogs fed different diets.
The metabolomic approach is becoming always more important in the evaluation of the functional responses of animals to dietary intervention.
NMR-metabolomics has emerged as a non-destructive technique that allows a simpler data interpretation compared to other techniques.
NMR metabolome analysis resulted to be a promising approach to describe the phenotypic variation that occurs among dogs fed different diets.
PDF
