A new CoII dimer with bridging bis­(pyrid­yl)pyrazolate ligands has been structurally characterized and its high-spin nature has been verified by DFT calculations. This work provides an important insight into the correlation between the structural features and the electronic properties of related CoII dimers with an implication of their relevance to reactivity in various types of catalysis.

The investigation focuses on a terphenyl com­pound functionalized with a carboxyl­ate and a hydroxyl group, located at opposite ends of the mol­ecule. The structures of the neutral acid, along with various anionic forms of the mol­ecule, including Zn coordination polymers, are described.

This study presents the first com­prehensive crystallographic characterization of salcaprozoic acid (HNAC), the free acid form of salcaprozate sodium (SNAC), using single-crystal X-ray diffraction. A well-organized hy­dro­gen-bonding framework underpins the robust crystal packing and thermal stability of the com­pound. Complementary IR spectroscopy highlighted the impact of hy­dro­gen bonding on vibrational modes.

In the presence of 4-[4-(1H-imid­a­zol-1-yl)phen­yl]pyridine (ipp), containing imidazole and pyridine groups, the carb­oxy­lic acid ligand 2-meth­oxy­terephthalic acid (H2mta) undergoes a self-assembly reaction with CoII ions, forming a three-dimensional coordination polymer, {[Co(mta)(ipp)]·H2O}n, with four distinct helical chains and a fivefold inter­penetration feature.

Acta Crystallographica Section C Structural Chemistry

A mol­ecule of sparsentan displaying a com­plex disorder of multiple sections was modelled and inter­preted with the assistance of energy calculations.

The crystal structures of eight com­pounds whose common features are an aromatic ring (naphthalene or benzene) and the presence of two hy­droxy­methyl groups or two sulfanylmethyl groups were examined. Different positions of the functional groups relative to each other are of fundamental importance in the way the mol­ecules of these com­pounds are packed in the unit cells and have an impact on the inter­actions of the mol­ecules of the com­pounds with each other.

The crystal structures of two closely related N-aryl­benzamides were determined experimentally using single-crystal X-ray diffraction. Predictions of the geometries of the gas-phase isolated conformers corresponding to mol­ecules in the crystals were performed with DFT calculations. Mol­ecular inter­action energies and Hirshfeld surfaces were used to examine differences in the energetics of nearest-neighbor inter­actions in the two crystalline environments in an attempt to explain any conformational changes that may occur upon crystallization of the isolated conformers.

Stimuli-responsive crystalline materials have demonstrated significant potential for developing multifunctional systems. Achieving precise structural modulation in non-porous crystalline phases remains a critical challenge. We report a solvatomorphic crystalline system which exhibits a reversible single-crystal-to-single-crystal transformation during aceto­nitrile adsorption/desorption, establishing a strategy for modulating optoelectronic properties in non-porous crystalline materials through solvent-mediated structural reorganization.

Greater solubility facilitated the isolation of the ortho-isomer from a CO2 elimination reaction that primarily produces the para-isomer [Pt{(p-BrC6F4)N(CH2)2NEt2}Cl(py)]. X-ray crystallography identified the syn and anti rotamers of [Pt{(o-BrC6F4)N(CH2)2NEt2}Cl(py)] in a 1:1 ratio in the solid state.

Two cocrystals of imidazo[1,2-a]pyridine-3-carbo­nitrile (IPC) with 4-nitro­benzoic acid (4-NBA) and 4-nitro­phenol (4-NP) have been synthesized and characterized by X-ray diffraction and Hirshfeld surface analysis, and their noncovalent inter­actions have been investigated.

Ce, Gd and Yb can accumulate as lanthanide phosphate structures in the alga Chlamydomonas reinhardtii supplemented with phosphate and may be a means of selective recovery of rare earths from solution. EXAFS structural analysis of some Ce, Gd and Yb com­pounds are presented.

The cleavage of the HIV-1 protease inhibitor indinavir sulfate via a one-pot synthesis reflux method with 1-propanol successfully yielded the salt bis­(2-hy­droxy-2,3-di­hydro-1H-inden-1-aminium) sulfate. The reported analysis provides com­prehensive insights into the chemical transformations, thermal stability and mol­ecular inter­actions of the salt, contributing to its characterization and potential pharmaceutical applications.

Celecoxib peroxide, a com­pound identified in destruction experiments and the long-term storage of the active pharmaceutical ingredient celecoxib, was synthesized and characterized using a variety of techniques.

(Z)-N-(4-Fluoro­phen­yl)-2-oxo­propane­hydrazonoyl chloride forms concomitant colour polymorphs, namely, block-shaped pale-orange crystals of form I (space group P21/n, Z = 4) and needle-shaped pale-yellow crystals of form II (space group P21/c, Z = 4).

[Nd(hfac)3(H2O)3]·3pdz (hfac is hexa­fluoro­acetyl­acetonate and pdz is pyridazine) was synthesized and the effect of the coordinated water mol­ecules and hy­dro­gen bonding on luminescence was investigated.

The crystal structure of a hydrated mol­ecular salt formed between 2-amino­thia­zole (AT) and 3,5-di­nitro­benzoic acid (DNBA) reveals a robust hy­dro­gen-bonded network, dominated by an R22(8) heterodimeric synthon between AT+ cations and DNBA− anions. This is extended into larger supra­molecular assemblies through N—H⋯O, OW—HW⋯O, OW—HW⋯OW and C—H⋯O inter­actions, forming R42(9), R65(17) and R88(40) motifs.

The hybrid halide [HCPP]2[ZnBr4] [HCPP is 4-(4-chloro­phen­yl)pyridinium] exhibits efficient blue emission centred at 432 nm with a photoluminescence quantum yield of 56.35%.

The structure of O-ethyl N-phenyl­thio­carbamate has been redetermined. Layers of hy­dro­gen-bonded dimers lie parallel to (031). A refinement using nonspherical scattering factors greatly reduced the number and severity of badly-fitting reflections.

The crystal structures of six new chro­mone derivatives have been determined and analysed using single-crystal X-ray diffraction. An analysis of the inter­molecular hy­dro­gen bonding was further supported by pairwise energy calculations and visualized using the energy framework approach.

The capacity of coumarin to be functionalized makes it an important mol­ecule for designing novel derivatives to treat autoimmune diseases. The total structural elucidation of new derivatives and in silico evaluation contributes to a better assessment of their potential bioactivities.

An overview of the development of electron diffraction and an introduction to the special issue Advances in Electron Diffraction for Structural Determination.