Chemistry and structure in Acta Crystallographica Section C

Acta Crystallographica Section C is continuing its transition to a journal that publishes exciting science with structural content, in particular important results relating to the chemical sciences.

Crystal structure refinement with SHELXL

New features added to the refinement program SHELXL since 2008 are described and explained.

PLATON SQUEEZE: a tool for the calculation of the disordered solvent contribution to the calculated structure factors

The SQUEEZE tool in the PLATON program is described. Using an iterated back-Fourier transform, it determines the contribution of a disordered solvent or ion to the calculated structure factors. The routine is discussed in the context of structure refinement with SHELXL.

3-Cyano-6-hy­droxy-4-methyl-2-pyridone: two new pseudopolymorphs and two cocrystals with products of an in situ nucleophilic aromatic substitution

3-Cyano-6-hy­droxy-4-methyl-2-pyridone (CMP) has been cocrystallized with 2,6-di­chloro­phenol, 4-amino-2-chloro-6-methyl­pyrimidine and 2-chloro-4,6-di­amino-1,3,5-triazine in N,N-di­methyl­acetamide, N,N-di­methyl­formamide and dimethyl sulfoxide, leading to two pseudopolymorphs of CMP and two cocrystals containing CMP and their nucleophilic aromatic substituted coformers.

Four (2,2′-bipyrid­yl)(ferrocen­yl)boronium derivatives

The B atom in four (2,2′-bipyrid­yl)(ferrocen­yl)boronium derivatives has a distorted tetra­hedral coordination. The B—N(amine) bonds are shortened by delocalization of π-electrons from the N to the B atom. The B—N(bipyrid­yl) bonds are longer in the cations with an amine substituent than in the cations with a methyl­ene C atom bonded to boron.

Crystallographic investigations of select cathinones: emerging illicit street drugs known as `bath salts'

The name `bath salts', for an emerging class of synthetic cathinones, is derived from an attempt to evade prosecution and law enforcement. The structures of five salts of MDPV (3,4-methyl­ene­dioxy­pyrovalerone) or ethyl­one are described, together with the serendipitous discovery of a new example of the H₂O–H₃O⁺–H₂O form of the H₇O₃⁺ cation.

A new tetra­gonal structure type for Li₂B₂C

Li₂B₂C crystallizes as a new structure type and consists of structural fragments which are typical for structures of elemental lithium and boron or binary borocarbide B₁₃C₂. Electronic structure calculations using the TB–LMTO–ASA method show strong B⋯C and B⋯B inter­actions.

Structure and magnetic properties of a mixed-ligand copper(II) complex

In a novel two-dimensional coordination polymer, phthalate ligands connect neighbouring Cu^II cations into an infinite one-dimensional chain. Adjacent one-dimensional chains are connected by naphthalene-1,4-dicarboxamide ligands, forming an intriguing two-dimensional framework. The magnetic properties and thermal stability of this complex are also described.

Two novel organic–inorganic hybrid materials from tetra­chlorido­metallate(II) salts and 4-[(E)-2-(pyri­din-1-ium-2-yl)ethenyl]pyridinium

Two organic–inorganic hybrid compounds have been prepared by the combination of the 4-[(E)-2-(pyridin-1-ium-2-yl)ethen­yl]pyridinium cation and perhalometallate [CoCl₄]²⁻ and [ZnCl₄]²⁻ anions. The cationic and anionic species are linked mainly through N—H⋯Cl and C—H⋯Cl hydrogen bonds and π–π contacts to form a three-dimensional hydrogen-bonded network.

On substituted pyrazole derivatives. II. (E)-1-(4-{[1-(4-Fluoro­phenyl)-3,5-di­methyl-1H-pyrazol-4-yl]diazenyl}phenyl)ethanone and (E)-1-(4-chloro­phenyl)-3,5-di­methyl-4-[2-(2-nitro­phenyl)diazenyl]-1H-pyrazole

The crystal structures of two substituted pyrazole derivatives are stabilized by the presence of C—H⋯O, C—H⋯π and π–π weak intermolecular interactions, and also by uncommon trifurcated C—Cl⋯Cl—C interactions that are discussed in detail.

Ethyl (4-benzyl­oxyphen­yl)-6-methyl-2-sulfanyl­idene-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate and a redetermination of ethyl (4RS)-4-(4-meth­oxy­phen­yl)-6-methyl-2-sulfanyl­idene-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate, as its 0.105-hydrate, both at 200 K: subtly different hydrogen-bonded ribbons

Two racemic 4-aryl-6-methyl-2-sulfanyl­idene-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate esters were prepared from simple precursors in a one-pot cyclo­condensation reaction. The mol­ecules are linked into different types of ribbon by a combination of N—H⋯O and N—H⋯S hydrogen bonds.

A three-dimensional anionic metal–dicyanamide network in poly[ethyl­tri­phenyl­phospho­nium [tri-μ₂-dicyan­amidato-cadmium(II)]]

Ethyl­tri­phenyl­phospho­nium (EtPh₃P⁺) cations fill voids in a three-dimensional anionic cadmium dicyanamide network. Each Cd^II atom is connected to six neighbouring Cd^II atoms through six separate dicyanamide ligands, forming cube-shaped cages. The three-dimensional anionic network encloses a solvent-accessible void space of 1851 ų, amounting to 69.3% of the unit-cell volume.

Three 1-phenyl­indolin-2-one derivatives displaying different mol­ecular dipole moments and different crystallographic symmetries

In 1-phenyl­indolin-2-one (Pbca), (I), 5-bromo-1-phenyl­indolin-2-one (P2₁/c), (II), and 5-iodo-1-phenyl­indolin-2-one (Aea2), (III), density functional theory (DFT) calculations show that the mol­ecular dipole moment gradually decreases in the order (I) > (II) > (III). The relatively smaller dipole moment of (III) and the larger non-electrostatic inter­molecular inter­actions may be the main reasons for the noncentrosymmetric and polar structure of (III).

Cocrystals of the anti­biotic trimethoprim with glutarimide and 3,3-di­methyl­glutarimide held together by three hydrogen bonds

Two supra­molecular complexes of the anti­biotic trimethoprim with glutarimide and its 3,3-dimethyl derivative are held together by three hydrogen bonds between the pyrimidine ring and the imide group. In both structures, the heterodimers and their constituents show similar conformations and hydrogen-bonding patterns, and also the crystal packings show similarities with an extended network of hydrogen bonds.

Ca₃ZnGeO₂[Ge₄O₁₂]: a Ca–Zn germanate related to the mineral taikanite

The crystal structure of the synthetic compound Ca₃ZnGeO₂[Ge₄O₁₂] was determined from single-crystal X-ray diffraction data and the close relationship of its structure to taikanite is revealed and discussed.