Notes for authors

New refinement of Ni_5.20Sn_8.7Zn_4.16Cu_1.04 and its non-isotypy with Ni₂Sn₂Zn

A new refinement of Ni_5.20Sn_8.7Zn_4.16Cu_1.04 based on the originally published structure factors was performed and indicates that the structure can be described in the centrosymmetric space group Pmm; no justification for the absence of the inversion centre could be found within the accuracy of the available data.

K₆[Fe_8.27(HPO₃)₁₂]: a new mixed-valence iron phosphite

The crystal structure of a mixed-valence iron phosphite has been solved from single-crystal X-ray diffraction data in the trigonal space group Rm. The compound shows anionic [Fe₃(HPO₃)₄]²⁻ and [Fe(HPO₃)₂]⁻ sheets stacked in a disordered manner along the c axis, with the K⁺ cations located in the inter­layer spaces.

MgAuGa and MgAu₂Ga: first representatives of the Mg–Au–Ga system

MgAuGa is the first ternary representative of the Mg–Au–Ga system. It adopts the Fe₂P structure type (Pearson symbol hP9) and closely resembles hexa­gonal Mg₂Ga through a direct group–subgroup relationship. MgAu₂Ga also crystallizes hexa­gonally and is isotypic with Na₃As. It adopts the structure of another binary compound, viz. Mg₃Au (hP8), but shows an unexpected distribution of Mg, Au, and Ga among the atomic positions of the asymmetric unit compared to Mg₃Au.

catena-Poly[[[4-amino-3,5-bis­(pyridin-2-yl)-4H-1,2,4-triazole-κ²N¹,N⁵](di­cyanamido-κN)copper(II)]-μ₂-dicyan­amido-κ²N:N′]: coordination polymer chains linked into a bilayer by hydrogen bonds and π–π stacking inter­actions

In a one-dimensional coordination polymer containing approximately square-pyramidal Cu^II, with one bridging and one terminal dicyanamide ligand, the polymer chains are linked by hydrogen bonds and π–π stacking inter­actions.

A mixed-valence complex of cobalt based on 3-meth­oxy­salicylaldoxime

The four Co atoms of a novel tetra­nuclear mixed-valence cobalt complex display distorted octa­hedral coordination environments and are bridged by two 2-[(oxido­imino)­methyl]-6-meth­oxy­phenolate ligands, two 2-[(hy­droxy­imino)­methyl]-6-meth­oxy­phenolate ligands and two azide anions to form a tetra­nuclear [Co₄N₄O₄] cluster. Adjacent clusters are connected through weak C—H⋯N and C—H⋯O inter­actions.

Chlorido­(2,3,7,8,12,13,17,18-octa­ethyl­porphyrinato)iron(III): a new triclinic polymorph of Fe(OEP)Cl

The structure of a new triclinic polymorph of Fe(OEP)Cl has been determined. The high-spin five-coordinate heme unit and axial ligation are essentially the same as previously determined, with an average Fe—N bond length of 2.075 (2) Å, an axial Fe—Cl bond length of 2.225 (4) Å, and the iron cation displaced by 0.494 (4) Å. Common features of the porphyrin plane–plane and supra­molecular stacking are identified. The main mol­ecular differences between the two polymorphs are in the orientations of the ethyl side chains on the periphery of the porphyrin core.

Synthesis, crystal structures and characterizations of two homochiral coordination polymers based on a chiral reduced Schiff base ligand

Two homochiral coordination polymers both have a three-dimensional network structure with a one-dimensional channel. An investigation of the photoluminescence properties shows that one of the compounds displays a strong emission in the purple region.

Counter-anion role in the formation of two supra­molecular complexes: [Ag₂(DPP)₂](ClO₄)₂·CH₃CN and [Ag₂(DPP)₂(NO₃)₂] {DPP is N-[(di­phenyl­phosphanyl)methyl]pyridin-4-amine}

In the Ag complex of N-[(di­phenyl­phosphanyl)methyl]pyridin-4-amine (DPP) with perchlorate, the unique Ag⁺ cation has a near-linear coordination geometry consisting of one pyridine N atom and one P atom from two different DPP ligands. In the analogous complex with nitrate, the nitrate anions weakly chelate to each Ag⁺ cation, leading to each Ag⁺ cation having a distorted tetra­hedral coordination geometry consisting of one pyridine N atom and one P atom from two different DPP ligands, and two chelating nitrate O atoms.

Structure and catalytic activity of the ruthenium(I) sawhorse-type complex [Ru₂{μ,η²-CF₃(CF₂)₅COO}₂(DMSO)₂(CO)₄]

A sawhorse-type dinuclear ruthenium complex with two bridging perfluoro­heptan­oate ligands and two dimethyl sulfoxide ligands in the axial positions is a new example of a compound with an aliphatic fluorinated carboxyl­ate ligand and a direct Ru—Ru inter­action. The compound is an active catalyst in transvinyl­ation of propionic acid with vinyl acetate.

Weak C—H⋯X (X = O, N) hydrogen bonds in the crystal structure of di­hydro­berberine

Di­hydro­berberine, a reduced form of pharmacologically important berberine, crystallizes from ethanol without inter­stitial solvent. Although lacking classical O—H or N—H donors, the packing in the crystalline state is clearly governed by C—H⋯N and C—H⋯O hydrogen bonds involving the two acetal-type C—H bonds of the 1,3-dioxole ring.

Cinnamic acid hydrogen bonds to isoniazid and N′-(propan-2-yl­idene)isonicotinohydrazide, an in situ reaction product of isoniazid and acetone

A new polymorph of the cinnamic acid–isoniazid cocrystal is characterized by hydrogen-bonded tetra­meric arrangements of two mol­ecules of isoniazid and two of cinnamic acid. Possible modification of the hydrogen bonding was investigated by changing the hydrazide group of isoniazid by an in situ reaction with acetone and cocrystallization with cinnamic acid.

Hydrogen bonding in polyamino-polyalcohols: a monohydrated cocrystal of 1,3-di­amino-5-azaniumyl-1,3,5-tri­deoxy-cis-inositol iodide and 1,3,5-tri­amino-1,3,5-tri­deoxy-cis-inositol

In a monohydrated cocrystal of 1,3,5-tri­amino-1,3,5-tri­deoxy-cis-inositol and its hydro­iodide salt, the cation, but not the neutral inositol unit, exhibits intra­molecular O—H⋯O hydrogen bonding. The neutral and cationic inositol entities are each aligned into chains along [001]. In these chains, two O—H⋯N inter­actions generate a ten-membered ring as the predominant structural motif.

Three different fluoro- or chloro-substituted 1′-de­oxy-1′-phenyl-β-D-ribo­furan­oses

The five-membered furan­ose ring of three fluoro- or chloro-substituted 1′-de­oxy-1′-phenyl-β-D-ribo­furan­oses has a conformation between a C2′-endo,C3′-exo twist and a C2′-endo envelope. The ribo­furan­ose groups are connected by O—H⋯O hydrogen bonds to symmetry-related mol­ecules to form layers. The orientation of the benzene ring is independent of the substitution pattern of the ring and depends mainly on crystal-packing effects.

The peptide Z-Aib-Aib-Aib-L-Ala-OtBu

A peptide is reported which is a left-handed helix with a right-handed conformation in the fourth residue, which is the only chiral residue. There are two 4→1 intra­molecular hydrogen bonds. In the crystal structure, mol­ecules are linked by hydrogen bonds along the c axis.

Four related benzazepine derivatives in a reaction pathway leading to a benzazepine carboxylic acid: hydrogen-bonded assembly in zero, one, two and three dimensions

Four related compounds exemplify the reaction sequence from a 1,4-ep­oxy­benzazepine ester via its reduction product, a benzazepin-4-ol ester, and the corresponding hy­droxy carb­oxy­lic acid, to a lactone as formed by intra­molecular condensation.

Supra­molecular structures in three thio­uracil derivatives: 5,6-tri­methyl­ene-2-sulfan­ylidene-1,2-di­hydro­pyrimidin-4(3H)-one, 2-(4-fluorobenzyl­sulfan­yl)-5,6-tri­methyl­ene­pyrimidin-4(3H)-one and methyl 2-{[2-(4-fluoro­benzyl­sulfan­yl)-5,6-tri­methyl­ene­pyrimidin-4-yl]­oxy}acetate

Three 5,6-tri­methyl­ene­pyrimidin-4-one derivatives display a combination of N—H⋯O, N—H⋯S, C—H⋯O and C—H⋯N hydrogen bonds. The study of the mol­ecular and supra­molecular structures of thio­uracil derivatives is significant in the development of lipoprotein-associated phospho­lipase A₂ inhibitors.