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ISSN: 2414-3146

June 2022 issue

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Cover illustration: Bis{[amino­(iminium­yl)meth­yl]urea} tetra­kis­{2-[(di­methyl­amino)(iminium­yl)meth­yl]guanidine} di-μ6-oxido-tetra-μ3-oxido-tetra­deca-μ2-oxido-octa­oxidodeca­vanadium(V) tetra­hydrate is a by-product obtained by reacting ammonium metavanadate(V), metformin hydro­chloride and acetic acid in the presence of sodium hypochlorite, at pH = 5. The crystal structure comprises a deca­vanadate(V) anion (V10O28)6– lying on an inversion centre, while cations and solvent water mol­ecules are placed in general positions, surrounding the anion, and forming numerous N—H⋯O and O—H⋯O hydrogen bonds. Metforminium (C4H12N5)+ and guanylurea (C2H7N4O)+ cations display the expected shape. Inter­estingly, in physiology the latter cation is known to be the main metabolite of the former one. The reported structure thus supports the role of sodium hypochlorite as an oxidizing reagent being able to degrade metformin hydro­chloride to form guanylurea. See: Pérez-Benítez, Ariza-Ramírez, Fortis-Valera, Arroyo-Carmona, Martínez de la Luz, Ramírez-Contreras & Bernès [IUCrData (2022). 7, x220627].

metal-organic compounds

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Crystallographic details are given of an unexpected product − a platinum(II) carbonyl complex, in which the carbonyl oxygen atom has remarkably been extracted from Pyrex glassware by tetra­fluoro­ethyl­ene. Preliminary details were reported previously.

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The isolated cluster unit in the structure of [Nb6Cl12I2(H2O)4]·8THF consists of an {Nb6} atom octa­hedron coordinated by twelve chlorido, four aqua, and two iodido ligands. THF solvent mol­ecules are bound via O—H⋯O hydrogen bonds.

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In the crystal structure of the title compound, numerous N—H⋯O and O—H⋯O hydrogen bonds of medium strengths connect metforminium and guanylurea cations and centrosymmetric deca­vanadate(V) anions into a three-dimensional network structure.

organic compounds

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The inner part of the ester substituent is nearly perpendicular to the di­hydro­pyridazine ring while the ipso carbon of the 4-meth­oxy­phenyl group is close to the above plane. In the crystal, corrugated layers parallel to the ab plane are formed by a combination of C—H⋯O, C—H⋯π(ring) and π-stacking inter­actions.

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The mol­ecules of the title compound are linked by weak N—H⋯N hydrogen bonds into [100] chains.

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The imidazolidine ring is slightly `ruffled' and the isobutyl substituent is rotated well out of the plane of its ring. In the crystal, inversion dimers are formed by pairs of N—H⋯O hydrogen bonds with C—H⋯O hydrogen bonds linking them into chains parallel to (10[\overline{1}]). The chains are joined into layers parallel to the ac plane by C—H⋯π(ring) inter­actions.

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The title compound, C8H4N4Te2, is the first reported [1,4]tellura[2,3-b:5,6-b′]di­pyrazine. Three independent unit-cell mol­ecules are folded along their Te⋯Te axes, with an average angle φ = 57.9°. C—Te—C angles range from 91.48 (6) to 93.80 (6)°. Inter­molecular N⋯Te bonding inter­actions between tellurium atoms of the central ring and the pyrazine N atoms of adjacent mol­ecules result in a supra­molecular helix motif.
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