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Techniques for Performing Stoichiometric Calculations
Published in Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk, Survival Guide to General Chemistry, 2019
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk
The limiting reagent is the reactant in shortest supply that limits the formation of product and, thus, determines the true theoretical yield. The excess reagents are those reagents, which are not completely consumed in the reaction (some amount leftover); these do not determine the theoretical yield.
Manganese dioxide nanosheets induce mitochondrial toxicity in fish gill epithelial cells
Published in Nanotoxicology, 2021
Cynthia L. Browning, Allen Green, Evan P. Gray, Robert Hurt, Agnes B. Kane
Time-resolved dissolution measurements were made on 8.7 μg/mL MnO2 nanosheets and microparticles in phagolysosomal simulant fluid (PSF) (pH 4.76) with and without 1 mM cysteine (Supplemental Table S4). A 5:1 molar equivalence ratio between reductant (cysteine) and MnO2 (requiring two electrons per mole for reduction from Mn(IV) to Mn(II)) was utilized to ensure that the reductant was not the limiting reagent in the experiment. The complete formulation of PSF is listed in Table S4. The effects of pH on MnO2 nanosheet dissolution were determined using 2% and 70% nitric acid solutions and a series of buffer solutions ranging from pH 3-8 (pH 3-4, potassium phthalate buffers and pH 6-8, phosphate based buffers). Dissolution was monitored by time-resolved measurement of total soluble Mn in subsamples following removal of nanosheets or particles by ultrafiltration. Solids were removed using a 20 nm Anatop filter and total dissolved Mn concentration in the filtrate was determined by a Thermo Scientific iCAPtm 7400 ICP-OES.
An overview of late-stage functionalization in today’s drug discovery
Published in Expert Opinion on Drug Discovery, 2019
Michael Moir, Jonathan J. Danon, Tristan A. Reekie, Michael Kassiou
The development of site-selective, intermolecular functionalization of isolated aliphatic C–H bonds is one of the most formidable challenges in organic chemistry. Rather than developing novel reaction manifolds to effect specific transformations, Czaplyski and coworkers have addressed the challenge of alkane functionalization by the site-selective installation of a highly versatile xanthate intermediate (Figure 5(a)) [51]. The C−H xanthylation proceeds in useful chemical yields with the substrate as the limiting reagent and an easily prepared N-xanthylamide under blue LED irradiation. The reaction tolerates a range of functional groups and is shown to be applicable to the LSF and diversification of complex molecules such as (+)-sclareolide where reaction occurs at a single site with 55% isolated yield on gram-scale. Further pharmaceutically relevant derivatization of the xanthate is demonstrated including azidation, deuteration, olefination and hydroxylation.
Activation of peroxymonosulfate into amoxicillin degradation using cobalt ferrite nanoparticles anchored on graphene (CoFe2O4@Gr)
Published in Toxin Reviews, 2021
Elham Babaei Lashkaryani, Babak Kakavandi, Roshanak Rezaei Kalantary, Ahmad Jonidi Jafari, Mitra Gholami
Although SO5•– species produce in the reaction between PMS with free sulfate radicals (in high PMS concentrations), the efficiency of system decreases which was due to the low oxidation ability of SO5•– radicals than free sulfate radicals (Golshan et al.2018). In fact, in high PMS concentrations, they can act as a limiting agent in free sulfate radical-based systems, which is in excellent consistent with other previous studies (Ling et al.2010).