Search

The copper(II) complex of the non-symmetric, bidentate ligand 2-{[6-(di­methyl­amino)­pyrimidin-4-yl]sulfan­yl}pyrimidine-4,6-di­amine exhibits distorted square pyramidal geometry around the metal centre, with disorder in the axial position, occupied by chloride or water. The six-membered metal–chelate ring is in a boat-conformation, and short inter­molecular S⋯S inter­actions are observed., A copper(II) complex of the non-symmetric bidentate ligand 2-{[6-(di­methyl­amino)­pyrimidin-4-yl]sulfan­yl}pyrimidine-4,6-di­amine (L1) is reported. The single-crystal X-ray structure of aqua­[aqua/chlorido­(0.49/0.51)](2-{[6-(di­methyl­amino)­pyrimidin-4-yl]sulfan­yl}pyrimidine-4,6-di­amine)­copper(II) 0.49-chloride 1.51-hydrate, [CuCl1.51(C10H13N7S)(H2O)1.49]Cl0.49·1.51H2O or [(L1)Cl1.51(H2O)1.49Cu]0.49Cl·1.51H2O, exhibits distorted square-pyramidal geometry around the metal centre, with disorder in the axial position, occupied by chloride or water. The six-membered metal–chelate ring is in a boat conformation, and short inter­molecular S⋯S inter­actions are observed. In addition to its capacity for bidentate metal coordination, the ligand has the ability to engage in further supra­molecular inter­actions as both a hydrogen-bond donor and acceptor, and multiple inter­actions with lattice solvent water mol­ecules are present in the reported structure.

The crystal structure of tricaesium citrate monohydrate, 3Cs+·C6H5O73−·H2O, has been solved and refined using laboratory X-ray single-crystal diffraction data, and optimized using density functional techniques. This compound is isostructural to the K+and Rb+compounds with the same formula. The three independent Cs cations are eight-, eight-, and seven-coordinate, with bond-valence sums of 0.91, 1.22, and 1.12 valence units. The coordination polyhedra link into a three-dimensional framework. The hydroxy group forms the usualS(5) hydrogen bond with the central carboxylate group, and the water molecule acts as a donor in two strong hydrogen bonds.

Flexible organic materials possessing useful electrical properties, such as ferroelectricity, are of crucial importance in the engineering of electronic devices. Up until now, however, only ferroelectric polymers have intrinsically met this flexibility requirement, leaving small-molecule organic ferroelectrics with room for improvement. Since both flexibility and ferroelectricity are rare properties on their own, combining them in one crystalline organic material is challenging. Herein, we report that trisubstituted haloimidazoles not only display ferroelectricity and piezoelectricity—the properties that originate from their non-centrosymmetric crystal lattice—but also lend their crystalline mechanical properties to fine-tuning in a controllable manner by disrupting the weak halogen bonds between the molecules. This element of control makes it possible to deliver another unique and highly desirable property, namely crystal flexibility. Moreover, the electrical properties are maintained in the flexible crystals., Mechanical flexibility gives organic ferroelectric materials a potential advantage over their inorganic counterparts, yet it is challenging to produce them. Owczarek et al. report flexible crystals based on trisubstituted haloimidazoles that show both ferroelectric and piezoelectric properties.

Crystals of the title compound, {[C8H14N2]3[Mo9O30]·2H2O}n, were grown under mild hydro­thermal conditions in the presence of p-xylylenediamine. [Mo9O30]n6n− chains, constructed from [MoO6] octa­hedra and [MoO4] tetra­hedra, are separated by protonated p-xylylenediaminium cations and occluded water mol­ecules, creating an extensive hydrogen-bonding network. One cation posseses a centre of symmetry; the anion is also centrosymmetric and one Mo atom lies on a crystallographic twofold rotation axis.

The title compound, {(C5H7N2)4[Mo8O26]}n, contains extended [Mo8O26]n4n− chains, built up from distorted MoO6 octa­hedra sharing vertices and edges. A network of N—H⋯O hydrogen bonds helps to stabilize the crystal packing.

The hydro­thermally synthesized title compound, {(C5H7N2)2[Mo3O10]}n, contains [Mo3O10]n2n− chains, which are generated through inversion symmetry. An extensive N—H⋯O hydrogen-bonding network is observed between the C5H7N2+ cations and the chains.

Crystals of the title compound, C6H4BrI, were obtained by growth on a two-dimensional self-assembled monolayer template. Single-crystal X-ray diffraction at 110 K revealed a centrosymmetric structure in which the center of the benzene ring lies on an inversion center and the halogen atoms are statistically disordered. The monoclinic structure reported here is isostructural with p-dibromo­benzene but not with p-diiodo­benzene.

Crystals of the title compound, 2-(dimethyl­ammonio)­ethanaminium hexa­cosa­oxaocta­molybdate(VI) dihydrate, containing extended chains constructed from centrosymmetric octa­molybdate anions, were grown under mild hydro­thermal conditions in the presence of N,N-dimethyl­ethylenediamine. An extensive hydrogen-bonding network helps stabilize the crystal structure.

Crystals of the title compound, 2,5-di­methyl­piperazinediium β-octamolybdate, were grown under mild hydro­thermal conditions. The anion and cations lie on inversion centers. A network of N—H⋯O bonds helps to stabilize the crystal packing.

Crystallography has long been a subject excluded from core curricula in undergraduate and graduate Chemistry programs. Occasionally offered as an elective or special topics course, crystallography remains a "black box" technique to many researchers who rely on it for verification of their work. Students interested in learning the theory and in-depth practical applications are often left to their own devices and seek out workshops, special courses, or one-on-one training. Currently, the authors host a ten-day intensive course on chemical crystallography, covering theory, hands-on experimental technique, and structure solution and refinement for both single crystal and powder X-ray diffraction. Here we describe the features of the course, the general curriculum and the demographics of attendees and faculty instructors.