Absolute structure of the chiral pyrrolidine derivative (2S)-methyl (Z)-5-(2-tert-but­oxy-1-cyano-2-oxo­ethyl­idene)pyrrolidine-2-carboxyl­ate, a com­pound with low resonant scattering

The light-atom com­pound (2S)-methyl (Z)-5-(2-tert-but­oxy-1-cyano-2-oxo­ethyl­idene)pyrrolidine-2-carboxyl­ate is an enanti­opure coordination partner for cations. Despite its only minor resonant scattering, the absolute structure was determined by a combination of diffraction, CD spectroscopy and theoretical calculations.

Unusual structure of a bi­phenyl fragment: the important role of weak inter­actions

Multiple noncovalent inter­actions can play a decisive role in both the mol­ecular and crystal structure of 1,5-bis­([1,1′-biphen­yl]-4-yl)-5-hy­droxy-3-methyl­heptane-1,6-dione.

Crystal structure and mesogenic behaviour of a new fluorene derivative: 9,9-di­methyl-2,7-bis­(4-pentyl­phen­yl)-9H-fluorene

A new mesogenic com­pound containing the fluorene moiety exhibits enanti­otropic nematic liquid crystalline behaviour with melting at 125 °C and isotropization at 175 °C. The crystallographically independent unit contains two mol­ecules oriented face-to-edge with respect to each other.

A novel crystal form of metacetamol: the first example of a hydrated form

The crystal structure and crystallization conditions of a novel form of metacetamol, the hemihydrate, are reported. Its crystal packing was analysed and compared with the packings of the two previously known polymorphs of metacetamol.

A new polymorph of phenyl­selenium trichloride

A new crystal form of PhSeCl₃ is reported. The primary structural feature is selenium–chlorine bridging inter­actions, forming noncovalent dimeric units.

A cyanide-bridged Fe^III–Mn^II heterobimetallic one-dimensional coordination polymer: synthesis, crystal structure, experimental and theoretical magnetism investigation

A new heterobimetallic cyanide-bridged Fe^III–Mn^II coordination polymer has been rationally designed and presents a cyanide-bridged cationic linear one-dimensional chain structure, with ClO₄⁻ as the charge-balancing anion, which is further expanded into a two-dimensional supra­molecular structure by inter­molecular π–π inter­actions. Both the experimental investigation and the theoretical calculations revealed an anti­ferromagnetic coupling between the cyanide-bridged Fe^III and Mn^II centres.

The low-temperature barium fluorido­zirconate variety α-BaZr₂F₁₀

The structure of the low-temperature triclinic variety α-BaZr₂F₁₀ is described and com­pared to the high-temperature β-variety directly recrystallizing from barium fluorido­zirconate glasses.

Ba₄YZr₃F₂₃ and Ba₄LnZr₃F₂₃: a new noncentrosymmetric potential host structure type for optical devices

The first ternary BaF₂–Ln(Y)F₃–ZrF₄ phases crystallizing near the com­position range of fluoride glasses, namely Ba₄YZr₃F₂₃ and isotypic Ba₄LnZr₃F₂₃ (Ln = Yb, Er and Nd), have been synthesized and their new noncentrosymmetric structure type described.

Crystal structure and pale-yellow emitting properties of K₃Gd_1–xDy_xB₆O₁₂ solid solutions

This work reports a new potassium dysprosium polyborate, K₃DyB₆O₁₂, that can be described as a three-dimensional framework com­posed of bicyclic [B₅O₁₀]⁵⁻ groups and Dy³⁺ and K⁺ ions. Moreover, a series of K₃Gd_1–xDy_xB₆O₁₂ phosphors was prepared and the photoluminescence properties were investigated.

Synthesis, crystal structure solution and characterization of two organic–inorganic hybrid layered materials based on metal sulfates and 1,4-phenyl­enedi­amine

The powder X-ray diffraction technique was used to determine the crystal structures of two new organic–inorganic hybrid materials forming three-dimensional networks composed of alternating organic and inorganic layers. Thermal stability tests of the materials indicated that one is stable up to 537 K and the other is stable up to 437 K.

Crystal structures of two (5,5,7,12,12,14-hexa­methyl-1,4,8,11-tetra­aza­cyclo­tetra­deca­ne)iron(III) com­plexes

The crystal structures presented herein consist of two positively charged Fe^III–HMC com­plexes, each of which was prepared from the pure meso- or rac-HMC ligand and which adopt trans or cis configurations, respectively.

A novel three-dimensional copper(I) cyanide coordination polymer constructed from various bridging ligands: synthesis, crystal structure and characterization

The title com­pound contains various types of bridging ligands which generate a three-dimensional structure. A photoluminescence study shows a blue photoluminescence originating from the Cu^I centre to the unoccupied π* orbital of the cyanide ligand.

ACr(C₂O₄)₂(H₂O)₄ (A = Li or Na): two new coordination polymers of low dimensionality with different hydrogen-bond networks

The structures of two new coordination polymers, ACr(C₂O₄)₂(H₂O)₄, with A = Li (C2/m) and Na (P), consist of alkali metal and Cr octa­hedra μ₂-bridged by oxalate ligands. The resulting one-dimensional chains are connected together through hydrogen-bond motifs, leading to two-dimensional frameworks. However, they differ in the crystal packing, the hydrogen-bond networks and the oxygen disorder in the former polymer.

Synthesis and structural characterization of the type-I clathrates K₈Al_xSn_46–x and Rb₈Al_xSn_46–x (x ≃ 6.4–9.7)

The crystal structure of several type-I clathrates with formulae K₈Al_xSn_46–x and Rb₈Al_xSn_46–x (x ≃ 6.4–9.7) have been accurately established from single-crystal X-ray diffraction data. Structural analysis shows the substitutional disorder on all three Sn sites and the presence of fully occupied guest atoms in both clathrate cages.

Polymorphism of 3-(5-phenyl-1,3,4-oxa­diazol-2-yl)- and 3-[5-(pyridin-4-yl)-1,3,4-oxa­diazol-2-yl]-2H-chromen-2-ones

Two derivatives of 3-(1,3,4-oxa­diazol-2-yl)-2H-chromen-2-one have been synthesized on the assumption of their potential anti­cancer activities and their poly­morphic modifications have been thoroughly studied. The method used for analysis, which was based on a com­parison of the pairwise inter­action energies between mol­ecules, allowed the differences in the crystal packing and the roles of different types of inter­molecular inter­actions to be elucidated.

Synthesis and structural study of organic two-photon-absorbing cyclo­alkanone chromophores

Three organic two-photon-absorbing cyclo­alkanone chromophores were obtained by a reaction between 4-(di­ethyl­amino)­benzaldehyde and the corresponding cyclo­alkanone. Mol­ecules of this series have three main fragments, i.e. a central acceptor (A) and two terminal donors (D₁ and D₂), and represent examples of the D₁–π–A–π–D₂ mol­ecular design.