Seventy years of publications

The IUCr, which was established 70 years ago, will be celebrating 70 years of peer-reviewed publications in 2018. Three of its journals, including IUCrJ, are ranked in the top 10% of all journals, with the remainder striving to be in the top quartile in the next five years.

Invariom-model refinement and Hirshfeld surface analysis of well-ordered solvent-free dibenzo-21-crown-7

The crystal structure of dibenzo-21-crown-7 is modelled using invarioms, as well as independent spherical atoms. Inter­molecular inter­actions are discussed and inter­preted based on analyses of the Hirshfeld surface, the electrostatic potential and computed inter­action energies.

Computational, ¹H NMR, and X-ray structural studies on 1-aryl­urazole tetra­zane dimers

ortho-Substituted 1-aryl­urazole radicals favor the formation of tetra­zane dimers rather than existing predominantly as independent free radicals like many other urazole radicals. The X-ray crystal structure of one of these dimers agreed well with a computational model and readily explained unusual shielding effects observed for some signals in the ¹H NMR spectrum.

Polymorphism of a widely used building block for halogen-bonded assemblies: 1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene

A new polymorph of 1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene is reported. On the basis of the experimental melting points and enthalpies, and also the calculated cohesion energies, the relative stabilities of both polymorphs have been established and analyzed in terms of the crystal structures and the noncovalent inter­actions present.

Three zinc(II) and cadmium(II) complexes containing 4-amino-3,5-bis­(pyridin-2-yl)-1,2,4-triazole and polynitrile ligands: synthesis, mol­ecular and supra­molecular structures, and photoluminescence properties

Three complexes containing either Zn^II or Cd^II coordinated by 4-amino-3,5-bis­(pyridin-2-yl)-1,2,4-triazole and polynitrile ligands have been synthesized, their structures determined and their photoluminescence properties explored.

Weak hydrogen and halogen bonding in 4-[(2,2-di­fluoro­eth­oxy)meth­yl]pyridinium iodide and 4-[(3-chloro-2,2,3,3-tetra­fluoro­prop­oxy)meth­yl]pyridinium iodide

To enable a comparison between a C—H⋯X hydrogen bond and a halogen bond, the structures of the two fluorous-substituted pyridinium iodide salts 4-[(2,2-di­fluoro­eth­oxy)meth­yl]pyridinium iodide and 4-[(3-chloro-2,2,3,3-tetra­fluoro­prop­oxy)meth­yl]pyridinium iodide have been determined.

Synthesis and characterization of (cryptand-222)potassium (2-methyl­imidazolato)(meso-tetra­phenyl­porphinato)ferrate(II)–2-methyl­imidazole–tetra­hydro­furan (1/1/2)

A salt of a (cryptand)potassium cation and a complex anion is described in which the central Fe^II atom is five-coordinated by an imidazolyl-substituted porphyrin and an imidazolate ligand.

Crystal structures and new perspectives on Y₃Au₄ and Y₁₄Au₅₁

Y₃Au₄ (triyttrium tetra­gold) and Y₁₄Au₅₁ (tetra­deca­yttrium henpenta­contagold), two binary representatives of Au-rich rare earth systems, crystallize with the space groups R and P6/m, adopting the Pu₃Pd₄ and Gd₁₄Ag₅₁ structure types, respectively.

A luminescent bis­(pyrid­yl)-substituted benz­imidazole platinum(II) complex exhibiting an inter­molecular anagostic inter­action

The luminescent complex di­chlorido­[5,6-dimethyl-2-(pyridin-2-yl)-1-(pyridin-2-ylmeth­yl)-1H-benzimidazole-κ²N²,N³]platinum(II) exhibits a weak inter­molecular anagostic Pt⋯H inter­action. DFT calculations were used to estimate the strength of the inter­action.

A bi­pyridine-ligated zinc(II) complex with bridging flavonolate ligation: synthesis, characterization, and visible-light-induced CO release reactivity

A bi­pyridine-ligated zinc–flavonolate complex exhibiting bridging flavonolate coordination has been characterized by single-crystal X-ray crystallography. In aceto­nitrile, this compound dissociates into monomers and undergoes visible-light-induced CO release.

A fluoro­phore-labelled copper complex: crystal structure, hybrid cyclic water–perchlorate cluster and biological properties

A fluoro­phore-labelled copper complex has been designed, synthesized and structurally characterized. A cyclic water–perchlorate anionic cluster, i.e. [(ClO₄)₂(H₂O)₂]²⁻, has been identified within the structure.

Hydrogen-bonded structures and inter­action energies in two forms of the SGLT-2 inhibitor sotagliflozin

The sotagliflozin mol­ecule exhibits two fundamentally different mol­ecular conformations in form 1 and the monohydrate. Hydrogen-bonded layer structures are based on inter­actions involving the –OH groups of the xyloside unit.

3-(Pyridin-4-yl)acetyl­acetone: Cd^II and Hg^II compete for nitro­gen coordination

With MBr₂ (M = Cd, Hg), 3-(pyridin-4-yl)acetyl­acetone forms bromide-bridged adducts having N—M bonds. When the Cd^II and Hg^II derivatives react in solution or in the solid simultaneously, the N-donor ligand is redistributed and exclusively binds to Cd^II, producing a well-ordered bimetallic chain polymer.

A phase transition caught in mid-course: independent and concomitant analyses of the monoclinic and triclinic structures of (ⁿBu₄N)[Co(orotate)₂(bipy)]·3H₂O

Repeated cycling through a reversible order–disorder phase transition in a crystal of a cobalt orotate complex produces an arrested transformation, leaving the sample with both triclinic and monoclinic domains. Independent determinations of the two structures were carried out from single-phase samples and the partial transition permitted simultaneous structure determination of the two phases at a temperature at which one of them is not expected to exist independently.

Supra­molecular architectures in the salt trimethoprimium ferrocene-1-carboxyl­ate and the cocrystal 4-amino-5-chloro-2,6-di­methyl­pyrimidine–ferrocene-1-carb­oxy­lic acid (1/1)

A salt, trimethoprimium (TMP) ferrocene-1-carboxyl­ate, and a cocrystal, 4-amino-5-chloro-2,6-di­methyl­pyrimidine (ACDPY)–ferrocene-1-carb­oxy­lic acid (1/1), have been synthesized and characterized by single-crystal X-ray diffraction. The supra­molecular architectures are generated by different hydrogen-bonding inter­actions, and weak stacking inter­actions stabilize both crystal structures.

A three-dimensional cadmium coordination polymer based on 1,4-bis­(1,2,4-triazol-1-yl)but-2-ene and benzene-1,3,5-tri­carb­oxy­lic acid

A unique three-dimensional cadmium(II) coordination polymer was prepared based on the self-assembly of Cd(NO₃)₂·4H₂O, benzene-1,3,5-tri­carb­oxy­lic acid and 1,4-bis­(1,2,4-triazol-1-yl)but-2-ene under hydro­thermal conditions. This coordination polymer can be simplified as a 4,6-connected framework with the point symbol (4²5²6²)(4²5⁹6².7.8).

A halide-free pyridinium-substituted η³-cyclo­hepta­trienide–Pd complex

A novel Pd^II complex bearing the zwitterionic [4-(di­methyl­amino)­pyridinium-1-yl]cyclo­hepta­trienide ligand, aside from solvent ligands, has been synthesized and its structure is discussed in comparison to the known halide-containing derivatives.