Themed collection International Year of Crystallography Celebration: North America

Welcome to this CrystEngComm themed issue celebrating the 2014 International Year of Crystallography in North America.

Conceptual density functional theory is exploited to extend the HSAB (hard and soft acids and bases) principle for investigating the locality and regioselectivity of intermolecular interactions in organic crystals.

The use of a laboratory cell lysis mill provides rapid, solvent-free access to m- and p-aminobenzoquinones, as well as the formation of their metal complexes.

Resorcin[4]arene capture of Mn²⁺ or Co²⁺ metals yields inclusion complexes 1, 2a and 2b.

A new crystalline sheet spontaneously assembled under mild conditions from tri-carbamates. The discovery of the unsaturated hydrogen bonded sheet further demonstrated the variety and adaptability of the sheet structures.

Replacing ortho-fluorine substituents on fluorinated azobenzenes with morpholine groups gives conformationally unusual molecules acting as halogen bond donors and acceptors.

Hydrogen- and halogen-bond donors competing for two different acceptor sites.

Task specific ionic liquids are employed in the development of two new low-dimensionality uranyl compounds.

A systematic study of metal–pseudorotaxane binding, using pseudorotaxanes derived from a rigid, linear axle and aromatic crown ethers, shows that metal complexes can be used to organize pseudorotaxane units into ordered 3D arrays, and that the construction of metal–organic frameworks from pseudorotaxanes is a viable approach.

A series of HCl salts of active pharmaceutical ingredients (APIs) have been characterized via³⁵Cl solid-state NMR (SSNMR) spectroscopy and first-principles plane-wave DFT calculations of ³⁵Cl NMR interaction tensors.

Various crystalline phases of uric acid are frequently identified components of human kidney stones, including anhydrous uric acid (UA) and uric acid dihydrate (UAD).

A series of linear oligoglycines has been studied to reveal the trends in their crystal structure, molecular conformation and thermally induced reactions.

Guest identification using SPME – a technique for analysis of TGA off-gas that eliminates the need for direct TGA-GC/MS coupling.

Intra-halogen bond J couplings measured via NMR spectroscopy and interpreted using natural localized molecular orbitals offer novel insights into this class of non-covalent interaction.

Dithiadiazolyl radicals containing chlorinated aromatic substituents adopt a β-sheet-like motif and exhibit the onset of paramagnetism upon warming to room temperature.

Single crystals of five new uranyl oxychlorides exhibiting novel layer topology, CCIs, chain structures, and/or luminescence were grown from molten chlorides. A comprehensive CCI classification is presented.

A family of 7 Tröger's base (TB) compounds that vary in configuration (quasiracemates, racemates, and enantiomers) and chemical substitutions (Me, Cl, and Br) has been investigated.

Amorphous nilutamide exhibits unusual nucleation and growth behavior upon crystallization, as well as the formation of different polymorphs.

Irradiation of single crystals of a benzonitrile substituted tetrathiafulvalene with polychromatic light results in a [2 + 2] cycloaddition reaction.

The cation selectivity of several uranyl structural units is examined in the context of five new uranyl compounds produced using the ionothermal synthesis technique.

The non-isomorphous crystal structures of “bridge-flipped” isomers 1–5 are described and are compared to those of recently reported fluorinated benzylideneanilines.

A first attempt to crystal-engineer classical clathrate hydrate frameworks using NH₄F incorporation has been successful. The modified lattices can form a stable methanol clathrate.