Twinning in 5-fluoro­salicylic acid: description of a new polymorph

A new polymorph of 5-fluoro­salicylic acid has been investigated. The packing basis for the pseudo-ortho­rhom­bic twinning is analysed, as are the structure-determining O—H⋯F hydrogen bonds.

The ephemeral dihydrate of sulfanilic acid

Sulfanilic acid dihydrate can be crystallized at 273 K. All H atoms attached to N and O atoms find an acceptor in suitable geometries and the packing is highly efficient; nevertheless, the compound undergoes fast desolvation under ambient conditions.

Two zinc(II) coordination complexes based on an asymmetric multidentate ligand: syntheses, structures, selective fluorescence sensing of iron(III) ions and thermal analyses

Two new Zn^II coordination complexes with the asymmetric multidentate ligand 1-(1H-benzotriazol-1-ylmeth­yl)-2-propyl-1H-imidazole have been synthesized and structurally characterized by single-crystal X-ray diffraction. The complexes were investigated by fluorescence and thermal analyses.

Sulfur as hydrogen-bond acceptor in cocrystals of 2-thio-modified thymine

Six cocrystal structures of 5-methyl-2-thio­uracil are presented whereby the mixed ADA–DAD N—H⋯S/N—H⋯N/N—H⋯O synthon was formed successfully with the coformers 2,4-di­amino­pyrimidine, 2,4-di­amino-6-phenyl-1,3,5-triazine and melamine, respectively. In addition, one cocrystal with 2,4-di­amino­pyrimidine containing an (8) N—H⋯O/N—H⋯N inter­action and two isomorphous solvated cocrystals with 6-amino-3H-isocytosine containing an (8) N—H⋯S/N—H⋯O inter­action are reported.

Substituent position effect on the crystal structures of N-phenyl-2-phthalimido­ethane­sulfonamide derivatives

2-Ethyl, 4-nitro and 4-meth­oxy substituents have an effect on the packing and inter­molecular inter­actions of N-phenyl-2-phthalimido­ethane­sulfonamide.

Synthesis, crystal structure and magnetic properties of di­aqua­bis­(2,6-di­amino-7H-purin-1-ium-κN⁹)bis­(4,4′-oxydibenzoato-κO)cobalt(II) dihydrate

A variable-temperature magnetic study of a Co^II complex incorporating 2,6-di­amino-7H-purin-1-ium, 4,4′-oxydibenzoate and water ligands between 2 and 300 K reveals an orbital contribution to the magnetic moment and a weak anti­ferromagnetic inter­action between the Co^II centres as the temperature decreases.

Four closely related N-(3-benzoyl-4,5,6,7-tetra­hydro­benzo[b]thio­phen-2-yl)benzamides: order versus disorder, and similar mol­ecular conformations but different modes of supra­molecular aggregation, with a new disordered refinement of 2-amino-3-benzoyl-4,5,6,7-tetra­hydro­benzo[b]thio­phene

Four variously substituted N-(3-benzoyl-4,5,6,7-tetra­hydro­benzo[b]thio­phen-2-yl)benzamides exhibit very similar mol­ecular conformations, but with conformational disorder in three of them. The supra­molecular assembly, involving C—H⋯O and C—H⋯π hydrogen bonds and π–π stacking inter­actions, ranges from finite zero-dimensional aggregates, via two types of chain, to complex sheets.

A chiral di­amine: practical implications of a three-stereoisomer cocrystallization

The structure resulting from a rare cocrystallization of three stereoisomers, i.e. RR, SS, and meso, of a di­amine has been used to compare seven methods for mol­ecular crystal-volume estimation.

A novel luminescent ionic trinuclear Cu₃I₂ cluster cuprous complex supported by a P^N ligand: synthesis, structure characterization, properties and TD–DFT calculations

In the ionic trinuclear Cu₃I₂ complex [Cu₃I₂(Ph₂PPy)₃]PF₆, three μ₂-bridging Ph₂PPy ligands strengthen the cluster core. A TD–DFT study demonstrates that the observed yellow phospho­rescence should be derived from the emissive ³(X+M)LCT excited state.

Z/E-Isomerism of 3-[4-(di­methyl­amino)­phen­yl]-2-(2,4,6-tri­bromo­phen­yl)acrylo­nitrile: crystal structures and secondary inter­molecular inter­actions

The crystal structures of the energetically similar Z and E isomers of 3-[4-(di­methyl­amino)­phen­yl]-2-(2,4,6-tri­bromo­phen­yl)acrylo­nitrile differ in the nature of their strong inter­molecular nonbonding inter­actions, which are Br⋯N in the case of the Z isomer and Br⋯Br for the E isomer.

Temperature-induced pseudopolymorphism of molecular salts from a pyridyl bis-urea macrocycle and naphthalene-1,5-di­sulfonic acid

Mol­ecular salts were formed by proton transfer from naphthalene-1,5-di­sulfonic acid to a pyridyl bis-urea macrocycle. Two DMSO-solvated salts displaying two distinct conformations of the macrocycle were obtained upon slow cooling of DMSO–aceto­nitrile solutions from two temperatures (363 and 393 K).

A series of (E)-5-(aryl­idene­amino)-1-tert-butyl-1H-pyrrole-3-carbo­nitriles and their reduction products to secondary amines: syntheses and X-ray structural studies

The synthesis and crystal structures of a series of (E)-5-(aryl­idene­amino)-1-tert-butyl-1H-pyrrole-3-carbo­nitriles and their respective reduced products are presented. Inter­estingly, C—H⋯Cl inter­actions seem to help in the construction of the supra­molecular structure of the precursors, while in the corresponding reduced compounds, these inter­actions appear less important compared with the observed (N,C)—H⋯N hydrogen bonds.

A two-dimensional Cd^II coordination polymer based on naphthalenedi­imide: synthesis, crystal structure and photochromic properties

A two-dimensional cadmium(II) coordination polymer has been prepared using the ligand N,N′-bis­(pyridin-4-ylmeth­yl)naphthalene-1,8:4,5-bis(dicarboximide). The product shows reversible photochromic behaviour and photocontrolled tunable luminescence properties.

Electrostatic properties of the pyrimethamine–2,4-di­hydroxy­benzoic acid cocrystal in methanol studied using transferred electron-density parameters

The cocrystal structure of an anti­malarial drug is reported along with a study of the electrostatic properties on the basis of transferred multipolar parameters from an electron-density database.

Molecular tapes in the structure of isoguaninium chloride

The structure of isoguaninium chloride displays two kinds of mol­ecular tapes parallel to (010) and (50). The tapes are formed by dimers of isoguaninium cations inter­acting with chloride anions.