Search results for "Reaction path"
showing 10 items of 17 documents
Medical Geochemistry
2013
Preface.- How trace element contents in bronchoalveolar lavages can probe the human exposure to inhaled particulates.- Geochemistry and Biochemistry - insights into the fate and transport of Pt-based chemotherapy drugs.- Atmospheric Particulate Matter (PM) in the Middle East: Toxicity, trans-boundary transport and influence of synoptic conditions.- Reaction path modeling: theoretical aspects and applications.- An observation on the composition of urinary calculi: environment influence.- Magnetite minerals in the human brain: what's their role?.- Chemometrics and Medical Geochemistry: A brief tutorial.- Dust, metals and metalloids in the environment: from air to hair.- Metal Geochemistry of …
Ruthenium‐assisted tellurium abstraction in bis(thiophen‐2‐yl) ditelluride
2023
The reaction of [RuCl2(CO)3]2 and Te2Tpn2 (Tpn = thiophen-2-yl, C4H3S) in the absence of light resulted in the formation of cct-[RuCl2(CO)2(TeTpn2)2] (1) [cis(Cl)-cis(CO)-trans(TeTpn2)] and TeTpn2 (2) together with the precipitation of tellurium. The complex 1 and the monotelluride 2 were characterized by NMR spectroscopy and single-crystal X-ray diffraction. The decomposition of Te2Tpn2 to TeTpn2 has been monitored by 125Te NMR spectroscopy and seemed to be faster than the ligand substitution in [RuCl2(CO)3]2 by TeTpn2. A catalytic cycle is proposed for the decomposition of Te2Tpn2 to TeTpn2 based on the PBE0-D3/def2-TZVP calculations. peerReviewed
Photocatalytic oxidation of nitrobenzene and phenylamine: Pathways and kinetics
2007
WOS: 000245150800018
1,2-Dipolar addition model for the cytoprotective activity of selected α,β-unsaturated compounds with CO functionality: an ab initio study
2001
Abstract The mechanism of the addition of a nucleophile (an alkylthiol group) to a double bond of α,β-unsaturated systems in the gas phase was explored. In this study, intermediates of the reaction were also investigated using ab initio calculations (RHF/6-31G ∗ and MP2/6-31+G ∗ ). Our results indicate that direct dipolar attack of the S–H group of an alkylthiol on the CC double bond is a reasonable reaction path. The present results represent, therefore, additional support for our hypothesis. This suggests that the mechanism of cytoprotection might be mediated, at least in part, by a reaction between the olefinic acceptor and the sulfhydryl-containing groups of the mucosa.
On the Reactivity of C(sp3)–H σ-Bonds: Oxygenation with Methyl(trifluoromethyl)dioxirane
2008
The reactivity of C–H σ-bonds of a series of 2-substituted adamantanes 2 towards methyl(trifluoromethyl)dioxirane (1) shows a consistent dependence on the electron-withdrawing ability, either inductive or by resonance, of the substituent. The results are interpreted in terms of the ability of the substrate molecule to delocalize the electronic perturbation of the reacting center at the beginning of the reaction path. The model shows that the electronic demand from the reacting C–H σ-bond is transmitted along the substrate through a chain of hyperconjugative interactions, the relative intensities of which depend on the σ-bonds involved. The substrate molecule simultaneously provides positive…
Rearrangement of N-(3-pyridyl)nitramine
2009
AbstractContrary to other N-(pyridyl)nitramines, the title compound cannot be rearranged to 3-amino-2-nitropyridine or other isomers. Hypothetical products of its transformation under influence of concentrated sulphuric acid, viz. 3-hydroxypyridine, 3,3′-azoxypyridine and 3,3′-azopyridine, were obtained from 3-nitro- and 3-aminopyridine in oxidation and reduction reactions. N-(3-Pyridyl)nitramine was prepared and rearranged in concentrated sulphuric acid. 3-Hydroxypyridine and 3,3′-azoxypyridine were isolated from the reaction mixture, other products were identified by the HPLC and GCMS methods. The results indicate that N-(3-pyridyl)hydroxylamine is an intermediate formed from N-(3-pyridyl…
CO Oxidation on Cationic Gold Clusters: A Theoretical Study
2008
Aiming at understanding the elementary steps governing the oxidation of CO catalyzed by dispersed or supported gold nanoclusters, the reactivity of molecular species, such as O2 and CO, on neutral and positively charged Au13 clusters have been studied using a DFT approach. Two CO oxidation mechanisms have been simulated, involving respectively the adsorption of CO and O2 on adjacent catalytic sites (two-sites mechanism) and the competitive interaction of the reactants on the same site (single-site mechanism). It is demonstrated that in the former scheme a definite interaction of CO and O2 with both the charged and neutral cluster is effective, but that a chemical reaction between the adsorb…
Quantitative models of hydrothermal fluid–mineral reaction: The Ischia case
2013
Abstract The intricate pathways of fluid–mineral reactions occurring underneath active hydrothermal systems are explored in this study by applying reaction path modelling to the Ischia case study. Ischia Island, in Southern Italy, hosts a well-developed and structurally complex hydrothermal system which, because of its heterogeneity in chemical and physical properties, is an ideal test sites for evaluating potentialities/limitations of quantitative geochemical models of hydrothermal reactions. We used the EQ3/6 software package, version 7.2b, to model reaction of infiltrating waters (mixtures of meteoric water and seawater in variable proportions) with Ischia’s reservoir rocks (the Mount Ep…
Mechanismus und Reaktionswege der Xanthenylierung an ambidenten nukleophilen Arzneistoffen
1986
Am Beispiel der ambidenten nukleophilen Arzneistoffe 4-Aminobenzolsulfonamid (3), Indometacin (7) und Phenylbutazon (10) werden Aralkylierungen mit dem SN1-aktiven Reagens Xanthydrol (1) vorgestellt. Mechanism and Reaction Path of the Xanthenylation of Ambident Nucleophilic Drugs The aralkylation of ambident nucleophilic drugs, e.g. 4-aminobenzenesulfonamide (3), indometacine (7) and phenylbutazone (10), with SN1-active xanthydrol (1) is described.
Reaction path models of magmatic gas scrubbing
2016
Gas-water-rock reactions taking place within volcano-hosted hydrothermal systems scrub reactive, water-soluble species (sulfur, halogens) from the magmatic gas phase, and as such play a major control on the composition of surface gas manifestations. A number of quantitative models of magmatic gas scrubbing have been proposed in the past, but no systematic comparison of model results with observations from natural systems has been carried out, to date. Here, we present the results of novel numerical simulations, in which we initialized models of hydrothermal gas-water-rock at conditions relevant to Icelandic volcanism. We focus on Iceland as an example of a "wet" volcanic region where scrubb…