issue contents

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

June 2000 issue

Highlighted illustration

Cover illustration: Conformational preferences in 2-nitrophenyl­thiol­ates: S-(2-nitro­phenyl) 4-toluenethio­sul­fon­ate. Ellipsoids are plotted at the 30% probability level and H atoms are shown as small spheres of arbitrary size. See Low, Glidewell & Wardell [Acta Cryst. C56, 689-691].

inorganic compounds


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Gd2OSe2 is the first rare-earth monooxy­gen diselenide to be characterized structurally. It is isostructural with the low-pressure form of Dy2OS2. Its structure comprises the close packing of Gd-centered bicapped trigonal prisms and Gd-centered distorted octahedra.

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CsTiP2O7 crystallizes in the KAlP2O7 structure type. It has a three-dimensional tunnel structure built by the corner-sharing of distorted TiO6 octahedra and P2O7 pyrophosphate groups. The Cs+ cations are in the tunnels.

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The new structure of La2(SeO3)3 consists of LaO10 polyhedra and SeO3 pyramids sharing faces, edges and vertices. The three-dimensional structure contains pseudo-channels associated with the SeIV lone pairs.

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The structure of monoclinic dipotassium dichromate consists of K+ cations and Cr2O72− dimers.

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The structure of RbLi2Ga2(BO3)3 is an ordered derivative of KZn(BO3)3. It exhibits a three-dimensional framework of BO3 triangles, and LiO4 and GaO4 tetrahedra that isolates the Rb atoms in channels extending along the b axis.

metal-organic compounds

















organic compounds
























electronic papers (inorganic compounds)


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Precise X-ray structure determinations of K3Na[FeCl6] have been performed at 293, 84 and 9.5 K.

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The title structure was redetermined at 120 K, confirming the hydrogen-bond pattern found at room temperature, but showing the librational corrections of bond lengths to be unrealistic. The octahedral coordination of Mg atoms is slightly distorted due to hydrogen bonding.

Acta Cryst. (2000). C56, e232
doi: 10.1107/S0108270100006855
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Crystals of KBa4Bi3O have been obtained from melting of the elements. The structure contains Bi24− dumbbells [Bi—Bi = 3.113 (3) Å] and isolated Bi3− anions coordinated by K and Ba atoms. O atoms lie at the centres of Ba tetrahedra.

electronic papers (metal-organic compounds)


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The four title CuII compounds, namely [Cu(fpy)Cl]ClO4, [Cu(etpa)Cl][CuCl4]1/2, [Cu(mopy)Cl]ClO4 and [Cu(pipy)Cl]PF6, where fpy is (2-furyl­methyl)­bis(2-pyridyl­methyl)­amine, etpa is 2-[bis(2-pyridyl­methyl)­amino]ethano­late, mopy is (2-morpholino­ethyl)­bis(2-pyridyl­methyl)­amine and pipy is (2-piperidinyl­ethyl)­bis(2-pyridyl­methyl)­amine, have potentially tetradentate tripodal ligands. In [Cu(fpy)Cl]ClO4 (shown opposite), the O atom of the furan moiety coordinates weakly to the Cu atom at a distance of 2.750 (3) Å.

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The title compound crystallizes from light petroleum with two independent mol­ecules in the asymmetric unit. In both mol­ecules, one of the three benzyl ligands is η2-bonded to the Zr atom, indicated by the smallest Zr—CH2Ph angle and the consequently relatively short Zr⋯Cipso distance.

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The structure of the cation in the title compound consists of the Cr atom bonded to the N atoms of the three 1,10-phenanthroline ligands, resulting in a distorted octahedral arrangement with the six Cr—N distances ranging from 2.040 (4) to 2.055 (4) Å. One of the perchlorate anions is disordered and is located around two special positions.

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The title compound is a centrosymmetric dimer. The terephthalate moiety acts as a bridging ligand and the phenanthrolines as terminal ligands. The unique Cu atom is coordinated by two O and four N atoms in a distorted octahedral geometry, with Cu—O distances of 1.955 (2) and 2.815 (2) Å, and Cu—N distances of 2.008 (2)–2.216 (2) Å.

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The isomorphous title compounds, (I>) and (II>), respectively, are monomeric and show distorted octahedral coordination with the monodentate dicyan­amide ligands in cis positions. In both mol­ecules, the metal–N(phenanthroline) bonds trans to the dicyan­amide ligands are significantly longer than the other two.

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The Ru atom in the title complex shows an octahedral coordination and a trans arrangement of the tri­phenyl­phosphine ligands. The observed bond lengths indicate a quinone rather than a di­amide form for the o-benzo­quinone di­imine ligand. The complex molecule, in a special position, has crystallographic twofold symmetry.

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The Ru atom in the title complex shows an octahedral coordination. The Cl ion and the aceto­nitrile mol­ecule are in the same plane as the o-benzo­quinone di­imine ligand, and the tri­phenyl­phosphine ligands are trans. Bond distances for the benzo­quinone di­imine ring establish a quinone arrangement.

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The title compound consists of a hexa­aqua­cobalt(II) cation and 4-toluene­sulfonate anions, with no direct coordination of the anion to cobalt. The Co atom, in an octahedral geometry, is on a centre of inversion. The supramolecular structure consists of parallel layers of cations and anions. The anions are arranged with their sulfonate groups directed towards the cation layer in an alternating fashion and form hydrogen bonds with the water mol­ecules of the cation.

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The title compound is photochromic. Comparison with related complexes indicates that complexation with tri­carbonyl­chromium has only minor effects on the structure of the chromene.

electronic papers (organic compounds)


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Our analysis of the title compound establishes its relative stereochemistry. The planar furan ring is twisted with respect to the steroid D ring and the crystal structure is stabilized by C—H⋯O hydrogen bonds and van der Waals interactions.

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The X-ray structure determinations of the di­hydro­chloride monohydrate, (I>), and the tri­hydro­chloride, (II>), of 7-methyl-3,7,11,17-tetra­aza­bi­cyclo­[11.3.1]­heptadeca-1(17),13,15-triene are reported. Protonation occurs at the secondary amine N atoms in (I>) and at all the three amine N atoms in (II>) to which the Cl ions are linked via N—H⋯Cl hydrogen bonds.

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Sulfonium salts are known as photo acid generators (PAG) and have found a wide range of uses in photo-optical applications. Comparing the cations in the title compounds, (I>) and (II>), respectively, there is no significant effect of the methyl/phenyl substituents on the bonding characteristics of the central S atom. As expected, in both cations, the S—Ph bonds are somewhat shorter than the S—Me bonds and the interactions between cations and anions, in both crystal structures, are similar.

Acta Cryst. (2000). C56, e259
doi: 10.1107/S0108270100006090
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The crystal structure of the title compound in the monoclinic space group C2/c has a columnar packing arrangement with a 7.20 Å axis, a feature common to several tetra­phenyl­methanes.

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In the two title adducts, (I>) and (II>), respectively, hydrogen bonds between the di­ammonium and carboxyl­ate ions form a two-dimensional network parallel to the ab plane in (I>) and one-dimensional chains along the c axis in (II>). The cyclohexanedi­ammonium ion in (II>) has a crystallographic twofold axis.

Acta Cryst. (2000). C56, e262
doi: 10.1107/S0108270100006156
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The title compound adopts a conformation with three cyano­ethyl groups oriented in the same direction, suggesting the compound may behave as a potential tripodal ligand.

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n-Butyl­ammonium di­hydrogen phosphate is ferro­elastic. Ferroelastic switching is concomitant with the hopping of some H atoms involved in hydrogen bonds from donor to acceptor O atoms.

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The title compound was found to exist as the endocis isomer with a pair of enantiomers in the asymmetric unit. The cyclo­hexene ring is folded about the methyl­ene-to-CH(acetoxy) vector to give a boat conformation.