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Methylisothiazolinone (MIT) is widely used as a biocide in numerous personal care products, glass-cleaning liquids, paints, and industrial applications. MIT and related isothiazolinones have attracted much attention for their allergenic properties such as contact dermatitis. Although the compound was first prepared in 1964 and has been widely used as a biocide since the 1970s, its crystal structure has so far not been reported. Here we report the solid state structure of MIT as determined by single crystal X-ray diffraction (SC-XRD) analysis of a crystal grown from the melt. MIT crystallizes as a layered structure with short C-H···O hydrogen bonding interactions within the sheets. The average distance between the sheets parallel to (1 0 2) is ca. 3.2 Å. The molecule exhibits a small C-S-N angle of 90.81(2)° and a methyl group that is slightly bent out of the plane of the planar five-membered ring. The sulfur atom does not undergo any significant intermolecular interactions.

The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT in the spring of 2004. In the configuration pioneered by the Autofib instrument at the Anglo‐Australian Telescope, Hectospec’s fiber probes are arranged in a radial “fisherman on the pond” geometry and held in position with small magnets. A pair of high‐speed, six‐axis robots move the 300 fiber buttons between observing configurations within ∼300 s, and to an accuracy of ∼25 μm. The optical fibers run for 26 m between the MMT’s focal surface and the bench spectrograph, operating at \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $R\\sim 1000{\\mbox{--}} 2000$ \\end{document} . Hectochelle, another high‐dispersion bench spectrograph offering \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $R\\sim 35,000$ \\end{document} , is also available. The system throughput, including all losses in the telescope optics, fibers, and spectrograph, peaks at ∼10% at the grating blaze in 1 \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $\\arcsec$\\end{document} FWHM seeing. Correcting for aperture losses at the 1 \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $\\farcs$\\end{document} 5 diameter fiber entrance aperture, the system throughput peaks at ∼17%, close to our prediction of 20%. Hectospec has proven to be a workhorse instrument at the MMT. Together, Hectospec and Hectochelle have been scheduled for \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $\\frac{1}{3}$ \\end{document} of the available nights since its commissioning. Hectospec has returned approximately 60,000 reduced spectra for 16 scientific programs during its first year of operation.

Trehalose conjugates of 3-hydroxychromone (3HC) dyes have previously been utilized as fluorescence labels to detect metabolically active mycobacteria with a view to facilitating point-of-care detection of mycobacterial pathogens, especially Mycobacterium tuberculosis. We subjected the 3HC dye 2-(6-(diethylamino)benzofuran-2-yl)-3-hydroxy-4H-chromen-4-one (3HC-2) to a combined X-ray crystallography and density functional theory (DFT) study, and conducted preliminary fluorescence labelling experiments with the model organism Mycobacterium aurum. In the crystal, 3HC-2 exhibits an s-cis conformation of the chromone and the benzofuran moieties about the central C–C bond. According to DFT calculations, the s-cis conformer is about 1.8 kcal mol−1 lower in energy than the s-trans conformer. The solid-state supramolecular structure features hydrogen-bonded dimers and π…π stacking. Fluorescence microscopy revealed fluorescence of M. aurum cells treated with the dye trehalose conjugate 3HC-2-Tre in the GFP channel. It was concluded that s-cis is the preferred conformation of 3HC-2 and that the generally considered non-pathogenic M. aurum can be labelled with the fluorescence probe 3HC-2-Tre for convenient in vitro drug screening of new antimycobacterial agents.

Business confidence is a measure of optimism or pessimism that managers feel about the commercial prospects for their organizations. This paper uses later medieval high-value English credit data as a proxy gauge of merchants’ business confidence or uncertainty. It discusses whether mercantile restriction of credit during the fifteenth-century recession reflects uncertainty, whereby merchants became increasingly risk-averse and so reduced the amount of credit they extended to their customers. It discusses the chronological trends in English lending between 1353 and 1532. This paper examines medieval debt restructuring and argues that this might similarly reflect merchants’ commercial confidence or uncertainty. In contrasting two sample years (1375 and 1433), the paper seeks to identify the motivations and influences that lay behind medieval merchants’ business decisions more fully. It argues that merchants’ investment behavior was guided more by local commercial circumstances than it was by profound economic shocks, such as plague and bullion famine.

In view of the rise of drug-resistant tuberculosis and difficult-to-treat related diseases caused by non-tuberculous mycobacteria, there is an urgent need for antimycobacterial drug discovery. Nα-aroyl-N-aryl-phenylalanine amides (AAPs) have been identified as antimycobacterial agents and are subject to lead optimization. The aim of the present study is to evaluate the impact of N-aryl ortho cyano substitution in a lead compound on the crystal and molecular structure and its in vitro activity against Mycobacterium abscessus. The title AAP can be conveniently synthesized from N-Boc-protected d-phenylalanine in two amide coupling steps using a previously established racemization-free method. Two polymorphic forms in the solid-state are described, as discovered by X-ray and electron diffraction. The introduction of a cyano group in the ortho position of the AAP N-aryl ring, however, leads to loss of in vitro activity against M. abscessus subsp. abscessus.

Knowledge about the absolute configuration of small bioactive organic molecules is essential in pharmaceutical research because enantiomers can exhibit considerably different effects on living organisms. X-ray crystallography enables chemists to determine the absolute configuration of an enantiopure compound due to anomalous dispersion. Here, we present the determination of the absolute configuration of the flavoring agent (+)-γ-decalactone, which is liquid under ambient conditions. Single crystals were grown from the liquid in a glass capillary by in situ cryo-crystallization. Diffraction data collection was performed using Cu-Kα radiation. The absolute configuration was confirmed. The molecule consists of a linear aliphatic non-polar backbone and a polar lactone head. In the solid state, layers of polar and non-polar sections of the molecule alternating along the c-axis of the unit cell are observed. In favorable cases, this method of absolute configuration determination of pure liquid (bioactive) agents or liquid products from asymmetric catalysis is a convenient alternative to conventional methods of absolute structure determination, such as optical rotatory dispersion, vibrational circular dichroism, ultraviolet-visible spectroscopy, use of chiral shift reagents in proton NMR and Coulomb explosion imaging.

4-(4-nitrophenyl)thiomorpholine, the title compound, has been used as a precursor for the corresponding 4-thiomorpholinoaniline, which is a useful building block in medicinal chemistry. The crystal and molecular structures of the title compound, however, have not been described thus far. We synthesized the title compound by means of a nucleophilic aromatic substitution reaction of 4-fluoronitrobenzene and thiomorpholine and structurally characterized it by X-ray crystallography, DFT calculations, and Hirshfeld surface analysis. In the crystal, the molecule exhibits an approximately CS-symmetric structure, with the nitrogen-bound 4-nitrophenyl group in a quasi axial position on the six-membered thiomorpholine ring in a low-energy chair conformation. The solid-state structure of the title compound is markedly different from that of its morpholine analogue. This can be ascribed to the formation of centrosymmetric dimers through intermolecular C–H···O weak hydrogen bonds involving the methylene groups adjacent to the sulfur atom and face-to-face aromatic stacking.

Crystals of Hg2[N(CN)2]2 were grown by a slow diffusion-reaction between aqueous Hg2(NO3)2·2H2O and Na[N(CN)2]. Hg2[N(CN)2]2 adopts the triclinic space group P 1 ¯ (no. 2) with a = 3.7089(5), b = 6.4098(6), c = 8.150(6) Å, α = 81.575(6)°, β = 80.379(7)°, γ = 80.195(7)°, and Z = 1. Crystals of Tl[N(CN)2] were obtained from the reaction of TlBr with Ag[N(CN)2] in water. Single-crystal structure analyses evidence that Tl[N(CN)2] is isotypic to α-K[N(CN)2] and adopts the orthorhombic space group Pbcm (no. 57) with a = 8.5770(17), b = 6.4756(13), c = 7.2306(14) Å, and Z = 4. Regarding volume chemistry, the dicyanamide anion occupies ca. 44 cm3·mol−1, and so it corresponds to a large pseudohalide. The IR spectra of both compounds exhibit vibrational modes that are characteristic of the dicyanamide anion.

Betaines of squaric acid have gained research interest because of their structural and spectral properties. We elucidated the crystal and molecular structure of the triethylammonium betaine of squaric acid (1) by X-ray crystallography, IR, and NMR spectroscopy augmented by Hirshfeld surface analysis and DFT calculations. The crystal structure determination using Hirshfeld atom refinement reveals that the resonance hybrid structure with partial enolate character of the two lateral squaric acid C=O groups describes 1 best. The solid-state supramolecular structure features weak intermolecular C−H···O hydrogen bonds. The number of C=O bands in the IR spectrum in the solid-state is consistent with local C2v symmetry of the squaric acid residue in 1. The 13C NMR signals of this group in solution were assigned based on 2D NMR experiments and computational prediction using the Gauge-Independent Atom Orbital (GIAO) method. The present study provides the first structural characterization of a betaine of squaric acid containing a four-coordinate nitrogen atom directly attached to the four-membered ring.