D. Bright

The crystal structure of 1,1′-dimethylferricenium tri-iodide

Abstract The crystal structure of 1,1′-dimethylferricenium tri-iodide has been determined from three-dimensional X-ray data collected by counter methods, and refined by least-squares techniques to a final conventional R factor, based on F, of 3.5%, for 1278 independent reflections. The material crystallizes in a triclinic cell, space group P 1 , with dimensions a = 14.70(1), b = 7.440(6), c = 7.97(1) A, α = 70.50(3)°, β = 81.49(3)° γ = 97.33 (4)°, Z = 2. Although the two independent tri-iodide anions in the structure lie at crystallographic centres, refinement of a structural model with a 50:50 disorder of asymmetric anions about the centres of symmetry gave a significantly better fit to the data than refinement of a model based on centrosymmetric anions. The II distances in the asymmetric anions are 2.85(2) 2.97(2) A for one, and 2.86(3) and 3.00(3) A for the other. The cyclopentadienyl rings in the cation are almost exactly eclipsed with the methyl groups adjacent. The rings are inclined at 6.6° to each other. Mean distances are Fe-ring (perpendicular) = 1.695(1), FeC(ring) = 2.073(5), CC(ring) = 1.401(5), CCH3 = 1.49(1) A.

Crystal and molecular structure of the chloroform solvate of bikaverin

The crystal and molecular structure of bikaverin, 7,10-dihydro-6,11-dihydroxy-3,8-dimethoxy-1-methyl-12H-benzo[b]xanthene-7,10,12-trione, has been determined at ca.–90 °C by single-crystal X-ray diffraction and the positions of all non-hydrogen atoms have been unambiguously determined. The space group is P21/c and cell dimensions are a= 9·26(1), b= 27·36(3), c= 10·26(1)A, and β= 109·15(5)°. All bond distances and angles are within the normal ranges. 1267 Independent reflexions were used in the refinement which was terminated at R= 8·4%.

Crystal structure analysis and strain-energy minimization calculations on a sterically crowded molecule: 1,8-dimethylnaphthalene

The crystal structure of 1,8-dimethylnaphthalene has been solved by a reciprocal space-search method. Least-squares refinement of 914 independent X-ray reflections measured on a diffractometer leads to R 0·080. The molecular distortions caused by steric interaction of the methyl groups have been analysed by means of strain-energy minimization calculations, which show that the repulsive energy between the methyl groups is reduced mainly by bond-angle distortion at the junction between the methyl groups and the naphthalene nucleus. Crystals are monoclinic, space group P21/c, Z= 4, a= 9·835(3), b= 7·012(3), c= 16·115(5)A, β= 124·35(3)°.

Crystal and molecular structure of NN-dimethylacetamidoxime

The crystal and molecular structure of the title compound, has been determined by a Fourier transform method from 665 unique X-ray diffraction intensities measured on a diffractometer, and refined by a least-squares procedure to R 4·5%. Crystals are triclinic, space group P, with cell parameters: a= 6·069(5), b= 7·582(5), c= 7·364(5)A, α= 84·97(5)°, β= 79·66(5)°, γ= 114·16(5)°, Z= 2. The molecules are associated in pairs through a hydrogen bond between the hydroxy-group of one molecule and the oxime nitrogen of a neighbouring species. The hydroxymoiety is syn(i.e. cis) to the methyl group.

Preparation and crystal structure of bis(triphenylphosphine)-(1,2-dimethylcyclopropene)platinum

The formation and crystal structure are reported of a thermally stable 1,2-dimethylcyclopropene–platinum(0) complex.