The structures of three doubly-acyl­ated 4-amino­anti­pyrine com­pounds where the aryl substituent is varied are reported and analysed in terms of their relative conformation, inter­molecular inter­actions and overall packing. The com­pounds were crystallized using the encapsulated nanodroplet crystallization (ENaCt) protocol.

Three pyridine-based halide-bibridged polymers have been synthesized and their structures determined. The effect of the size of the halides on the crystal structures has been investigated.

The mol­ecular structures of two novel cobalt amino­diphosphine (PNP) com­plexes are reported, featuring variation in the N-atom substituent. A Cambridge Structural Database (CSD) survey, along with a noncovalent inter­action (NCI) analysis of the analogous [TMCln(PNP)2] (where TM = transition metal and n = 1 or 2) core, revealed an inverse correlation between the P—TM—P bite angles and N⋯TM contact distances.

The role of inter­molecular inter­actions in the 1:1 gallic acid–N-methyl­urea cocrystal was characterized using Hirshfeld surface analysis and energy-framework approaches. Special attention was paid to the system of O—H⋯O and N—H⋯O hy­dro­gen bonds that links the com­ponents into dimeric com­plexes. The possibility of proton transfer within this supra­molecular heterosynthon was examined using quantum-chemical calculations.

MgNi2B6 crystallizes as a new representative of the CeCr2B6 structure type. The coordination polyhedra around the Mg atoms are based on centred hexa­gonal prisms. The environment of the Ni atom is a 10-vertex polyhedron. The B atoms form an eight-membered channel along b, which is filled with Mg and Ni atoms. Electronic structure calculations show a strong B–B inter­action.

The crystal structure of the metastable form of S-ibu­pro­fen–nicotinamide cocrystals was solved from powder X-ray diffraction data and explains the main mechanisms responsible for the relative stability of the two forms of the cocrystals. This also made it possible to explain the transition mechanism between the two forms with tem­per­a­ture.

The performance of the Hirshfeld atom refinement (HAR) and transferable aspherical atom model (TAAM) approaches in crystal structure refinement and the determination of the nature of chemical bonds is com­pared for a series of quinone-like com­pounds, known for single–double bond alternation. The HAR approach is shown to adequately reproduce the bond alternation in the electron-density distribution, while the TAAM approach does not perform as well in such specific cases.

Powder diffraction is a widespread technique found in academic, forensic, industrial research and quality-control laboratories the world over. The recent article by Kabova et al. [(2025), Acta Cryst. C81, 559–569] provides step-by-step guidance on how to proceed and the software the authors use, from sample preparation and the powder diffraction measurement itself, to the verification of the final structure.

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.