3,5,6-Tri-chloro-pyridin-2-ol.

The title compound, CHClNO, is almost planar. In the crystal, the mol-ecules form centrosymmetric hydrogen-bonded dimers through pairwise O-H⋯N inter-actions to generate (8) loops.

Structure of 2,3,5-tri-phenyl-tetra-zol-3-ium chloride hemi-penta-hydrate.

The title hydrated mol-ecular salt, CHN ·Cl·2.5HO, has two tri-phenyl-tetra-zolium cations, two chloride anions and five water mol-ecules in the asymmetric unit. The cations differ in the conformations of the phenyl rings with respect to the heterocyclic core, most notably for the C-bonded phenyl ring, for which the N-C-C-C torsion angles differ by 36.

Synthesis, spectroscopic analysis and crystal structure of (-{2-[(2-amino-eth-yl)amino]-eth-yl}-4'-methyl-[1,1'-biphenyl]-4-sulfonamidato)tri-carb-on-ylrhenium(I).

The title compound, [Re(CHNOS)(CO)] is a net neutral -Re(I)(CO) complex of the 4-methyl-biphenyl sulfonamide derivatized di-ethyl-enetri-amine ligand. The NNN-donor monoanionic ligand coordinates with the Re core in tridentate fashion, establishing an inner coordination sphere resulting in a net neutral complex. The complex possesses pseudo-octa-hedral geometry where one face of the octa-hedron is occupied by three carbonyl ligands and the other faces are occupied by one nitro-gen atom of the sulfonamide group and two nitro-gen atoms of the dien backbone.

Crystal structures of the isomeric dipeptides l-glycyl-l-me-thio-nine and l-me-thionyl-l-glycine.

The oxidation of me-thionyl peptides can contribute to increased biological (oxidative) stress and development of various inflammatory diseases. The conformation of peptides has an important role in the mechanism of oxidation and the inter-mediates formed in the reaction. Herein, the crystal structures of the isomeric dipeptides Gly-Met (Gly = glycine and Met = me-thio-nine) and Met-Gly, both CHNOS, are reported.

Resolution and Resolving Power in Mass Spectrometry.

The term resolution is one of the most important in mass spectrometry because it describes the ability to separate peaks in mass spectra. The term resolving power is often used to describe the ability of a mass spectrometer to resolve adjacent peaks in a mass spectrum and is often used interchangeably with resolution. The separation of peaks for singly charged ions can be expressed as a mass difference and the ratio is often given as a quantitative measure of the ability of a mass spectrometer to separate ions.

3D Macroporous Zinc Compound/Silicone Hybrid Foams for Amperometric Sensing of Glucose Oxidase.

A 3D porous matrix makes an intriguing sensing platform, which can integrate functional guest molecules. Here, the first demonstration of a zinc compound/silicone hybrid foam is reported for amperometric sensing of glucose oxidase. The silicone foam is fabricated by a self-developed solid-filling-melting method.

Realization of a Type-II Nodal-Line Semimetal in MgBi.

Nodal-line semimetals (NLSs) represent a new type of topological semimetallic phase beyond Weyl and Dirac semimetals in the sense that they host closed loops or open curves of band degeneracies in the Brillouin zone. Parallel to the classification of type-I and type-II Weyl semimetals, there are two types of NLSs. The type-I NLS phase has been proposed and realized in many compounds, whereas the exotic type-II NLS phase that strongly violates Lorentz symmetry has remained elusive.

Temporal Control of Gelation and Polymerization Fronts Driven by an Autocatalytic Enzyme Reaction.

Chemical systems that remain kinetically dormant until activated have numerous applications in materials science. Herein we present a method for the control of gelation that exploits an inbuilt switch: the increase in pH after an induction period in the urease-catalyzed hydrolysis of urea was used to trigger the base-catalyzed Michael addition of a water-soluble trithiol to a polyethylene glycol diacrylate. The time to gelation (minutes to hours) was either preset through the initial concentrations or the reaction was initiated locally by a base, thus resulting in polymerization fronts that converted the mixture from a liquid into a gel (ca.

Infrared emission of organic compounds stimulated by a laser beam.

A modified long-pathlength cell is described for laser-excitation of infrared emission spectra. The sensitivity of detection is about 1 ng l . for acetone and methyl iodide.