Poly[μ-(1,3-dihy­droxy­propan-2-olato)-potassium]

The asymmetric unit of the title compound, [K(C3H7O3)]n or K[H2gl]n, common name potassium glycerolate, contains half the K+ cation and half of the glycerolate anion. The other half of the anion is generated through a mirror plane passing through the K atom, and a C, an H and an O atom of the glycerolate ligand. The K+ ion is coordinated by the O atoms of the OH groups, leading to a six-membered chelate ring that adopts a very distorted boat conformation. The negatively charged O atom of the glycerolate anion, [H2gl−], is found in the flagpole position and forms an ionic bond with the K+ ion. The O atoms of the hydroxo groups are coordinated to two K+ ions, whereas the negatively charged O atom is bonded to one K+ ion. The K+ ion is coordinated by three other symmetry-related monodentate H2gl− ligands, so that each H2gl− ligand is bonded to two K+ ions, and the potassium has a seven-coordinate environment. The H2gl− ligands are connected via a strong O—H⋯O hydrogen bond and, together with the K⋯O inter­connections, form polymeric sheets which propagate in the directions of the a and b axes

Biomolecular Interaction Study of Cyclolinopeptide A with Human Serum Albumin

The kinetics, energetics, and structure of Cyclolinopeptide A binding with Human Serum Albumin were investigated with surface plasmon resonance and circular dichroism. The complex is formed through slow recognition kinetics that is temperature sensitive in the range of 20°C–37°C. The overall reaction was observed to be endothermic (ΔH = 204 kJ mol−1) and entropy driven (ΔS = 746 J mol−1K−1) with overall small changes to the tertiary structure

Electrocatalytic Oxidation of Nitrophenols via Ag Nanoparticles Supported on Citric-Acid-Modified Polyaniline

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).Government of Canada through the Natural Sciences and Engineering Research Council of Canada as a Discovery Grant (RGPIN 04315-2021) awarded to LDW. MK acknowledges the partial support provided by the University of Saskatchewan through the award of a Graduate Teaching Fellowship (GTF).Peer ReviewedCitric-acid-modified polyaniline (P-CA) and P-CA modified with Ag nanoparticles (Ag@PCA) were prepared via an in situ reduction method. The physicochemical properties of P-CA and Ag@P-CA were compared to unmodified polyaniline (PANI) and PANI-modified Ag nanoparticles (Ag@PANI). Ag@P-CA had a lower content of aniline oligomers compared to Ag@PANI. P-CA and Ag@P-CA had a greater monolayer adsorption capacity for 2-nitrophenol and lower binding affinity as compared to PANI and Ag@PANI materials. X-ray photoelectron spectroscopy and cyclic voltammetry characterization provided reason and evidence for the higher conductivity of citric-acid-modified materials (P-CA and Ag@P-CA versus PANI and Ag@PANI). These results showed the potential utility for the optimization of adsorption/desorption and electron transfer steps during the electrochemical oxidation of nitrophenols. The oxidation process employs Ag@P-CA as the electrocatalyst by modifying polyaniline with Ag nanoparticles and citric acid, which was successfully employed to oxidize 2-nitrophenol and 4-nitrophenol with comparable selectivity and sensitivity to their relative concentrations. This work is envisaged to contribute significantly to the selective conversion of nitrophenols and electrocatalytic remediation of such waterborne contaminants

Poly[μ-2,3-dihydroxy­propan-1-olato-sodium]

The Na+ cation in the title compound, [Na(C3H7O3)]n or Na[H2gl], is coordinated by five O atoms leading to a distorted trigonal-bipyramidal geometry. The negatively charged O atom of the glycerolate anion is in an equatorial position, and the O atom of the hydroxo group, attached to the secondary C atom, occupies an axial position completing a five-membered non-planar chelate ring; this defines the asymmetric unit. The Na+ cation is coordinated by three other symmetry-related monodentate H2gl− ligands, so that each H2gl− ligand is bonded to four Na+ ions. The H2gl− ligands are connected via strong O—H⋯O hydrogen bonds and these, together with the Na⋯O inter­connections, are responsible for the formation of polymeric sheets which propagate in the directions of the b and c axes

Cyclo­linopeptide B methanol tris­olvate

The title compound, C56H83N9O9S·3CH3OH, is a methanol tris­olvate of the cyclo­linopeptide cyclo(Met1—Leu2—Ile3—Pro4—Pro5—Phe6—Phe7—Val8—Ile9) (henceforth referred to as CLP-B), which was isolated from flaxseed oil. All the amino acid residues are in an l-configuration based on the CORN rule. The cyclic nona­peptide exhibits eight trans peptide bonds and one cis peptide bond observed between the two proline residues. The conformation is stabilized by an α-turn and two consecutive β-turns each containing a N—H⋯O hydrogen bond between the carbonyl group O atom of the first residue and the amide group H atom of the fourth (α-turn) or the third residue (β-turns), repectively. In the crystal, the components of the structure are linked by N—H⋯O and O—H⋯O hydrogen bonds into chains parallel to the a axis

Cyclo­linopeptide K butanol disolvate monohydrate

The title compound, C56H83N9O11S·2C4H10O·H2O, is a butanol–water solvate of the cyclo­linopeptide cyclo(Metsulfone1-Leu2–Ile3–Pro4–Pro5–Phe6–Phe7–Val8–Ile9) (henceforth referred to as CLP-K) which was isolated from flax oil. All the amino acid residues are in an l configuration based on the CORN rule. The cyclic nona­peptide exhibits eight trans peptide bonds and one cis peptide bond observed between the two proline residues. The conformation is stabilized by an α- and a β-turn, each containing an N—H⋯O hydrogen bond between the carbonyl group O atom of the first residue and the amide group H atom of the fourth (α-turn) and the third residue (β-turn), repectively. In the crystal, the components of the structure are linked by inter­molecular N—H⋯O and O—H⋯O hydrogen bonds into a two-dimensional network parallel to (001). The –C(H2)OH group of one of the butanol solvent mol­ecules is disordered over two sets of sites with refined occupancies of 0.863 (4) and 0.137 (4)

Electronic structure, effective spin Hamiltonian expressions, and experimental evidence for the parallel electron paramagnetic resonances of matrix-Isolated (η6−C5H5)V(\eta^{6}-C_{5}H_{5})V and (η6−C5D6)V(\eta^{6}-C_{5}D_{6})V half sandwich complexes.

Author Institution: Department of Chemistry, University of New BrunswickBenzene and perdeutrobenzene are reacted with vanadium atoms and matrix-isolated m Ar at 12 K. The resulting $(\eta^{6}-C_{6}H_{6})V, (\eta^{6}-C_{6}H_{6})V, (\eta^{6}-C_{6}H_{6})_{2}V,$ and $(\eta^{6}-C_{6}H_{6})_{2}V$, compounds are investigated by electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra are well resolved and the parallel features of the resonances due to the $g_{zz^{\prime}}$, $a_{zz}(^{3}1V)$, and $a_{xx}(^{1}H)$ tensor components are identified experimentally for the first time. Spectral features of $(\eta^{6}-C_{6}H_{6})V$, and $(\eta^{6}-C_{6}H_{6})V$, such as the resonance field positions and intensities, are all analyzed and accounted for by computer simulation. The effective spin Hamiltonian tensor components and resonance field positions are derived in terms of their molecular orbital coefficients. The magnetic properties, such as the g, hyperfine and superhyperfine tensor components are compared with those computed using the local-density-functional (LDF) approximation. Both the experimental spectra and electronic structure computations confirm that the $(\eta^{6}-C_{6}H_{6})V$, and $(\eta^{6}-C_{6}H_{6})V$ complexes have $^{2}A_{1}$ ground states

Chemicals Production from Glycerol through Heterogeneous Catalysis: A Review

Utilization of biofuels generated from renewable sources has attracted broad attention due to their benefits such as reducing consumption of fossil fuels, sustainability, and consequently prevention of global warming. The production of biodiesel causes a huge amount of by-product, crude glycerol, to accumulate. Glycerol, because of its unique structure having three hydroxyl groups, can be converted to a variety of industrially valuable products. In recent decades, increasing studies have been carried out on different catalytic pathways to selectively produce a wide range of glycerol derivatives. In the current review, the main routes including carboxylation, oxidation, etherification, hydrogenolysis, esterification, and dehydration to convert glycerol to value-added products are investigated. In order to achieve more glycerol conversion and higher desired product selectivity, acquisition of knowledge on the catalysts, the type of acidic or basic, the supports, and studying various reaction pathways and operating parameters are necessary. This review attempts to summarize the knowledge of catalytic reactions and mechanisms leading to value-added derivatives of glycerol. Additionally, the application of main products from glycerol are discussed. In addition, an overview on the market of glycerol, its properties, applications, and prospects is presented