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The title complex, [Cu(C 8 H 18 NO 5 )Cl] or [Cu(H 4 bis-tris-)Cl], was obtained starting from the previously reported [Cu(H 5 bis-tris-)Cl]Cl compound. The deprotonation of the amino-polyol ligand H 5 bis-tris {[bis-(2-hy-droxy-eth-yl)amino]-tris-(hy-droxy-meth-yl)methane, C 8 H 19 NO 5 } promotes the formation of a very strong O-H⋯O inter-molecular hydrogen bond, characterized by an H⋯O separation of 1.553 (19) Å and an O-H⋯O angle of 178 (4)°. The remaining hy-droxy groups are also engaged in hydrogen bonds, forming R 2 2 (8), R 4 4 (16), R 4 4 (20) and R 4 4 (22) ring motifs, which stabilize the triperiodic supra-molecular network., (© Fortis-Valera et al. 2024.)

The use of acetic acid (HOAc) in a reaction between CuCl 2 ·2H 2 O and secnid-azole, an active pharmaceutical ingredient useful in the treatment against a variety of anaerobic Gram-positive and Gram-negative bacteria, affords the title complex, [CuCl 2 (C 7 H 11 N 3 O 3 ) 2 ]. This compound was previously synthesized using ethanol as solvent, although its crystal structure was not reported [Betanzos-Lara et al. (2013 ▸). Inorg. Chim. Acta , 397 , 94-100]. In the mol-ecular complex, the Cu 2+ cation is situated at an inversion centre and displays a square-planar coordination environment. There is a hydrogen-bonded framework based on inter-molecular O-H⋯Cl inter-actions, characterized by H⋯Cl separations of 2.28 (4) Å and O-H⋯Cl angles of 175 (3)°. The resulting supra-molecular network is based on R 2 2 (18) ring motifs, forming chains in the [010] direction., (© Angel-Nieto et al. 2024.)

The title mol-ecule, C 12 H 15 NO 5 , is a methyl carbamate derivative obtained by reacting ( R )-2-phenyl-glycinol and methyl chloro-formate, with calcium hydroxide as heterogeneous catalyst. Supra-molecular chains are formed in the [100] direction, based on N-H⋯O hydrogen bonds between the amide and carboxyl-ate groups. These chains weakly inter-act in the crystal, and the phenyl rings do not display significant π-π inter-actions., (© Mendoza Herrera et al. 2024.)

The chemical formula of the title compound, 2C 17 H 17 N 4 + ·2C 7 H 5 O 5 - ·C 17 H 16 N 4 ·2.94C 4 H 8 O 2 , was established by X-ray diffraction of a single-crystal obtained by reacting 1,3-bis-(benzimidazol-2-yl)propane ( L ) and gallic acid (HGal) in ethyl acetate. The mol-ecular structure can be described as a salt (H L ) + (Gal) - co-crystallized with a mol-ecule L , with a stoichiometric relation of 2:1. Moreover, large voids in the crystal are filled with ethyl acetate, the amount of which was estimated by using a solvent mask during structure refinement, affording the chemical formula (H L + ·Gal - ) 2 · L ·(C 4 H 8 O 2 ) 2.94 . The arrangement of components in the crystal is driven by O-H⋯O, N-H⋯O and O-H⋯N hydrogen bonds rather than by π-π or C-H⋯π inter-actions. In the crystal, mol-ecules and ions shape the boundary of cylindrical tunnels parallel to [100] via R (rings) and D (discrete) supra-molecular motifs. These voids, which account for about 28% of the unit-cell volume, contain disordered solvent mol-ecules., (© Palacios Rodríguez et al. 2023.)

The title compound, C 29 H 46 O 3 , is a steroid synthesized through a rearrangement of a sarsasapogenin derivative in acidic medium. The newly formed ring F is a tetra-hydro-2 H -pyran heterocycle substituted by two methyl groups placed in equatorial positions. This ring displays a chair conformation, while di-hydro-furan ring E , to which it is bonded, has an envelope conformation. The mol-ecules are associated by weak O-H⋯O hydrogen bonds to form chains running in the [101] direction in the crystal., (© Guerrero-Luna et al. 2023.)

The title salt, C 14 H 14 N 3 O 4 S 2 + ·Cl - [systematic name: 2-(4-hy-droxy-2-methyl-1,1-dioxo-1,2-benzo-thia-zine-3-amido)-5-methyl-1,3-thia-zol-3-ium chloride] is the hydro-chloride derivative of meloxicam, a drug used to treat pain and inflammation in rheumatic disorders and osteoarthritis. Although its mol-ecular structure is similar to that previously reported for the hydro-bromide analogue, both salts are not isomorphous. Different crystal structures originate from a conformational modification, arising from a degree of rotational freedom for the thia-zolium ring in the cations. By taking as a reference the conformation of meloxicam, the thia-zolium ring is twisted by 10.96 and -16.70° in the hydro-chloride and hydro-bromide salts, while the 1,2-benzo-thia-zine core is a rigid scaffold. This behaviour could explain why meloxicam is a polymorphous compound., (© Flores Manuel et al. 2023.)

The plastic phase of cyclohexane (polymorph I) was studied by Kahn and co-workers, without achieving a satisfactory determination of the atomic coord-inates [Kahn et al. (1973). Acta Cryst . B 29 , 131-138]. The positions of the C atoms cannot be determined directly as a consequence of the disorder in a high-symmetry space group, an inherent feature of plastic materials. Given this situation, the building of a polyhedron describing the disorder was the main tool for determining the molecular structure in the present work. Based on the shape of reflections {111}, {200} and {113} in space group Fm 3 m , we assumed that cyclohexane is disordered through the action of rotation group 432. The polyhedral cluster of disordered molecules is then a rhombic dodecahedron centred on the nodes of an fcc Bravais lattice. The vertices of this polyhedron are the positions of C atoms for the cyclohexane molecule, which is disordered over 24 positions. With such a model, the asymmetric unit is reduced to two C atoms placed on special positions, and an acceptable fit between the observed and calculated structure factors is obtained., (© Bernes and Camargo 2023.)

The title mol-ecule, C 14 H 14 O 6 , is based on a benzene core di-substituted by allyl carbonate groups in the para positions. The mol-ecule is placed on an inversion centre, and the substituents are twisted with respect to the central benzene ring plane. The crystal structure does not include significant inter-molecular inter-actions other than weak C-H⋯O contacts between CH groups in the benzene ring and carbonate O atoms., (© López-Velázquez et al. 2023.)

The title Sn IV complex, [Sn(C 6 H 5 ) 3 Cl(C 18 H 15 O 4 P)], is a formal adduct between triphenyl phosphate (PhO) 3 P=O and the stannane derivative chlorido-tri-phenyl-tin, SnPh 3 Cl. The structure refinement reveals that this mol-ecule displays the largest Sn-O bond length for compounds including the X =O→SnPh 3 Cl fragment ( X = P, S, C, or V), 2.6644 (17) Å. However, an AIM topology analysis based on the wavefunction calculated from the refined X-ray structure shows the presence of a bond critical point (3,-1), lying on the inter-basin surface separating the coordinated phosphate O atom and the Sn atom. This study thus shows that an actual polar covalent bond is formed between (PhO) 3 P=O and SnPh 3 Cl moieties., (© Pouye et al. 2023.)

The title compound, C 20 H 16 N 2 O 6 (systematic name: 4-hy-droxy-phenyl N -{4-[(4-hy-droxy-phen-oxy-carbon-yl)amino]-phen-yl}carbamate), contains two urethane groups substituting the central benzene ring in para positions. The mol-ecule is centrosymmetric, and displays a twisted conformation for the three aromatic rings [the dihedral angle between central benzene ring and the urethane group is 33.4 (6)°, and that between the latter and the terminal ring is 65.1 (1)°]. In the crystal, a three-dimensional framework is formed through O-H⋯O and N-H⋯O hydrogen bonds involving the hy-droxy and urethane functional groups, respectively., (© Martínez-de la Luz et al. 2022.)

The title metal-organic polymer, catena-poly[[(5,5'-dimethyl-2,2'-bipyridine-κ 2 N,N')iron(II)]-di-μ-azido-κ 2 N 1 :N 3 -[(5,5'-dimethyl-2,2'-bipyridine-κ 2 N,N')iron(II)]-di-μ-azido-κ 2 N 1 :N 1 ], [Fe(N 3 ) 2 (C 12 H 12 N 2 )] n , features alternating μ-1,1 (end-on mode of coordination) and μ-1,3 (end-to-end mode of coordination) double azide bridges, forming chains running in the [100] direction. The octahedral coordination geometry around the Fe II centre is completed by a bidentate 5,5'-dimethyl-2,2'-bipyridine ligand. Two polymorphs for this compound were obtained from the crude reaction product, the first in the space group P-1 and the other in P2 1 /c. The molecular and crystal structures are very similar for both forms, the main difference being that the eight-membered Fe(μ-1,3-N 3 ) 2 Fe metallacycle formed with end-to-end azide ligands has a nearly flat conformation in the triclinic form and a chair conformation in the monoclinic form. In spite of this geometric difference, both forms have the same density, the same packing index and similar arrangements of the one-dimensional chains in the crystal. As a consequence, they also share very similar Hirshfeld surfaces and fingerprint plots. However, a density functional theory (DFT) computational study showed that the monoclinic form is more stable than the triclinic form by ca 30.5 kJ mol -1 .

The title compound, (C 4 H 12 N 5 ) 4 (C 2 H 7 N 4 O) 2 [V 10 O 28 ]·4H 2 O, is a by-product obtained by reacting ammonium metavanadate(V), metformin hydro-chloride and acetic acid in the presence of sodium hypochlorite, at pH = 5. The crystal structure comprises a deca-vanadate(V) anion (V 10 O 28 ) 6- lying on an inversion centre in space group P , while cations and solvent water mol-ecules are placed in general positions, surrounding the anion, and forming numerous N-H⋯O and O-H⋯O hydrogen bonds. Metforminium (C 4 H 12 N 5 ) + and guanylurea (C 2 H 7 N 4 O) + cations display the expected shape. Inter-estingly, 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 hydro-chloride to form guanylurea., (© Pérez-Benítez et al. 2022.)

The synthesis of new chiral highly functionalized zwitterionic bicyclic lactams starting from acyclic β-enaminoesters derived from ( R )-(-)-2-phenylglycinol is described. The key step involved an intramolecular non-classical Corey-Chaykovsky ring-closing reaction of the corresponding sulfonium salts derived from β-enaminoesters. This methodology permits the generation of two or three new stereogenic centers with high diastereoselectivity. The utility of these intermediates was demonstrated by the stereocontrolled total synthesis of cis -4-hydroxy-2-methyl piperidine and its corresponding pipecolic acid derivative., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)