issue contents
June 2020 issue
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Cover illustration: Ethyl (3S)-3-[(3aR,5R,6S,6aR)-6-hydroxy-2,2-dimethyltetrahydrofuro[4,5-d][1,3]dioxol-5-yl]-3-{(3S)-3-[(3aR,5R,6S,6aR)-6-hydroxy-2,2-dimethyltetrahydrofuro[4,5-d][1,3]dioxol-5-yl]-5-oxoisoxazolidin-2-yl}propanoate chloroform monosolvate was obtained as a product of a double aza-Michael addition of hydroxylamine on a Chiron with a known absolute configuration. The enantiopure compound crystallized as a chloroform solvate, in space group P1, and diffraction data were collected at room temperature with Ag K
radiation. The Flack parameter refined to x = -0.01 (16); however, the Flack and Watkin 2AD plot clearly shows that differences between Friedel opposites (the D component of the plot) do not carry any reliable information about resonant scattering of Cl atoms, and are rather dominated by random and systematic errors. This example illustrates that while using Ag K
radiation (
= 0.56083 Å), scatterers heavier than Cl should be present in a chiral crystal in order to determine confidently the absolute structure of the crystal. See: Amaro Hernández, Rodríguez Tzompantzi, Dávila García, Meza-León & Bernès [IUCrData (2020). 5, x200788].
metal-organic compounds
The title compound consists of a centrosymmetric bimetallic complex charge-balanced by free 4-nitrobenzoate anions. Each CoII ion exhibits a distorted cis-CoN2O4 octahedral coordination environment. In the crystal, the dications and anions are linked by O—H⋯O and C—H⋯O hydrogen bonds.
Pairs of bis-monodentate 5-nitro-2-phenylsulfanyl-benzoate ligands bridge two CuII atoms related by inversion symmetry. The square-pyramidal coordination geometry of each copper(II) atom is completed by an acetronitile ligand at the apex. The intramolecular Cu⋯Cu distance in the dimer is 2.6478 (3) Å.
organic compounds
The molecular structure of the title compound, (BenzMIm)Br (BenzMIm=1-benzyl-3-methylimidazolium), consists of separated bromide anions and 1-benzyl-3-methylimidazolium cations connected via short C—H⋯Br contacts.
The title compound was prepared via a Claisen-Schmidt condensation through a solventless, green synthesis technique. The resulting crystals formed in the monoclinic space group P21/c, and adopting the common E configuration.
The crystal structure of a pharmacophore hybrid of chalcone and resveratrol is reported.
The Flack and Watkin 2AD plot based on 1941 acentric Friedel pairs for the title chloroform solvate shows that the observed intensity differences for Friedel opposites are dominated by random and systematic errors, erasing information about resonant scattering.
In the title molecule, the phenyl rings areinclined to one another by 48.04 (9)°. In the crystal, weak C—H⋯π(ring) interactions form a layered structure.
In the title hemisolvate, the dihedral angles between the central heterocyclic ring and pendant benzene rings are 82.9 (8) and 88.7 (9)° and the complete benzene solvent molecule of crystallization is generated by a crystallographic centre of inversion. In the crystal, one very weak C—H⋯I interaction links the molecules into [001] chains.