Di­iodo­durene: four centrosymmetric mol­ecules in general positions

Di­iodo­durene (1,4‐diodo‐2,3,5,6‐tetra­methyl­benzene), C₁₀H₁₂I₂, packs with four mol­ecules in the asymmetric unit. All four of these moleules violate Kitaigorodsky's suggestion that mol­ecules with centers of symmetry will lie on crystallographic centers of symmetry. There is 5.6% disorder at one of the sites. Most of the I atoms are in contact with other I atoms, but only six of the I⃛I contacts are shorter than 4.2 Å. Of these six contacts, one set of three contacts forms a triangular set in which all of the I⃛I distances are less than 3.9 Å.     

2,7,12,17‐Tetraoxa‐3,4:5,6:13,14:15,16‐tetrabenzo­dispiro­[8.1.8.0]­nona­decane

The reaction of bi­phenyl‐2,2′‐diol with 1,1,2,2‐tetrakis­(bromo­methyl)­cyclo­propane leads to two products, namely a propellane‐type compound and a di­spiro‐type compound. The molecular structure of 4,5;6,7‐dibenzo‐3,8,12‐tri­oxa[8.3.1]­propellane has been determined previously by spectroscopic methods. The crystal structure of the di­spiro product, 2,7,12,17‐tetraoxa‐3,4:5,6:13,14:15,16‐tetrabenzodi­spiro[8.1.8.0]­nona­decane, C₃₁H₂₆O₄, revealed that the conformations of the nine‐membered heterocyclic rings are due to interactions between the π‐electron system of the bi­phenyl moiety and the lone electron pairs of the ether O atoms, the repulsion of the lone electron pairs of atoms O1⃛O2 and O3⃛O4, and steric interactions between H atoms in ortho positions. The conformations have C₁ symmetry and can be described approximately as twist‐boat.     

Old friends in a new light: “SnSb” revisited

The binary pnictide ‘SnSb’ has been re-investigated using a combination of X-ray, synchrotron and electron diffraction as well as electron microprobe analysis. Its structure was found to be incommensurately modulated with an underlying rhombohedral parent structure of space group symmetry (No. 166), unit cell parameters , in the hexagonal setting. The incommensurate primary modulation wave vector and the superspace group symmetry is (0, 0, ∼1.311) (No. 166.1). The refinement of the incommensurate structure indicates that the satellite reflections arise from displacive shifts of presumably essentially pure Sn and Sb layers along the hexagonal c-axis, with increasing distance between the Sn-layers and decreasing distance between the Sb layers.     

Multicentre hydrogen bonds in a 2:1 aryl­sulfonyl­imidazol­one ­hydro­chloride salt

The title compound, (S)‐(+)‐4‐[5‐(2‐oxo‐4,5‐di­hydro­imidazol‐1‐yl­sulfonyl)­indolin‐1‐yl­carbonyl]­anilinium chloride (S)‐(+)‐1‐[1‐(4‐amino­benzoyl)­indoline‐5‐sulfonyl]‐4‐phenyl‐4,5‐di­hydro­imidazol‐2‐one, C₂₄H₂₃N₄O₄S⁺·Cl^?·C₂₄H₂₂N₄O₄S, crystallizes in space group C2 from a CH₃OH/CH₂Cl₂ solution. In the crystal structure, there are two different conformers with their terminal C₆ aromatic rings mutually oriented at angles of 67.69 (14) and 61.16 (15)°. The distances of the terminal N atoms (of the two conformers) from the chloride ion are 3.110 (4) and 3.502 (4) Å. There are eight distinct hydrogen bonds, i.e. four N—H?Cl, three N—H?O and one N—H?N, with one N—H group involved in a bifurcated hydrogen bond with two acceptors sharing the H atom. C—H?O contacts assist in the overall hydrogen‐bonding process.     

Microdialysis SPR: diffusion-gated sensing in blood

Chemical measurements are rarely performed in crude blood due to the poor performance of sensors and devices exposed to biofluids. In particular, biosensors have been severely limited for detection in whole blood due to surface fouling from proteins, the interaction of cells with the sensor surface and potential optical interference when considering optical methods of analysis. To solve this problem, a dialysis chamber was introduced to a surface plasmon resonance (SPR) biosensor to create a diffusion gate for large molecules. This dialysis chamber relies on the faster migration of small molecules through a microporous membrane towards a sensor, located at a specified distance from the membrane. Size filtering and diffusion through a microporous membrane restricted the access of blood cells and larger biomolecules to a sensing chamber, while smaller, faster diffusing biomolecules migrated preferentially to the sensor with limited interference from blood and serum. The affinity of a small peptide (DBG178) with anti-atherosclerotic activity and targeting type B scavenger receptor CD36 was successfully monitored at micromolar concentrations in human serum and blood without any pre-treatment of the sample. This concept could be generally applied to a variety of targets for biomolecular interaction monitoring and quantification directly in whole blood, and could find potential applications in biochemical assays, pharmacokinetic drug studies, disease treatment monitoring, implantable plasmonic sensors, and point-of-care diagnostics.     

Organomonophosphines in PtP<Subscript>2</Subscript>XY derivatives: structural aspects

This review covers over two hundred Pt(II) complexes with a PtP₂XY inner coordination sphere, in which the P-donor ligands are organomonophosphines. These complexes can be divided into six groups: PtP₂HX (X = O, N, B, Cl, S, Br, Se, Si, or I); PtP₂OX (X = N, Cl, S, or Se); PtP₂NX (X = CN, Cl, B, S, Br, Se, or Te); PtP₂BX (X = F, Cl, S, Br, or I); PtP₂ClX (X = S, Se, Si, As, or Te); and PtP₂SiX (X = Br or Te). The complexes crystallize in several crystal systems: hexagonal (×1), tetragonal (×1), orthorhombic (×22), triclinic (×78), and monoclinic (×130). There are complexes with cis-configuration and trans-configuration, the latter by far prevails. Besides monodentate ligands, there are also heterobidentate ligands with: O/N, O/S, O/Se, N/S, N/Se, and N/Te, donor sites. These chelating ligands form a wide variety of metallocyclic, four-, five-, and six-membered rings, and the effects of both steric and electronic factors can be seen from the values of the L–Pt–L bite angles. The structural parameters are analyzed and discussed with particular attention to trans-influences.     

“蒸馏酒”还是“发酵酒”——对《科学史导论》中“spirits” 和“distillation”的再思考

科学史奠基者乔治·萨顿在《科学史导论》第二卷的第一部分对我国宋代酿酒著作《北山酒经》予以了简要描述,出现了“spirits”“distillation”等字样;而《北山酒经》被众多学者认为其描述对象是发酵酒(黄酒)。本文从东西方蒸馏技术和相关著作的文本分析对《科学史导论》中提及的蒸馏技术和蒸馏酒存在的可能性提出了质疑。     

Spin-spin Coupling Constants <Superscript>13</Superscript>C-<Superscript>13</Superscript>C in Structural Studies: XXXVIII. Nonempirical Calculations: Oximes

Ab initio calculation of spin-spin coupling constants ¹³C-¹³C for a series of ketone oximes was carried out in a framework of the second order polarization propagator approximation (SOPPA). Taking into account the electron correlation effects and the use of special correlation-consistent basic sets including functions allowing for internal correlation and dense functions provided a good agreement between the calculated and experimental values. These results open new possibilities for the configurational assignment of imine nitrogen compounds.