The crystal structure of thenoyltrifluoroacetonatocarbonyltriphenylphosphinerhodium (I)

The crystal structure of thenoyltrifluoroacetonatocarbonyltriphenylphosphinerhodium (I), [Rh(TTA) (CO) PPh₃], has been determined by single crystal X-ray diffraction. 2665 independent observed reflections were used for the structure determination. The crystals are monoclinic, space group P2₁/n with a = 13.26Å; b = 10.86Å; c = 18.92Å; β = 69.8° with four molecules in the unit cell. The final R value for all the reflections was 0.052. The compound was prepared by substitution of one of the carbonyl groups in Rh(TTA) (CO)₂ by triphenylphosphine. The structure determination shows that the carbonyl group trans to the oxygen nearest to the thenoyl ring was substituted by the phosphine group. The distance between the rhodium atom and the latter oxygen atom is 0.033Å longer than the other RhO distance.     

The crystal structure of bis-trimethylbenzylammoniumtetrachlorocuprate (II)

The crystal structure of bis-trimethylbenzylammonium tetrachlorocuprate (II) was determined. The structure for the [CuCl₄]^2– ion proposed in the spectroscopic work, i.e. a flattened tetrahedron of D _2d, symmetry, was confirmed. It was shown, further, that the four S ₄ axes of the four [CuCl₄]^2– ions in the unit cell are practically parallel, because they lie almost parallel to the glide planes of symmetry. This fact proved to be of great importance for further collection and elaboration of spectral data. The unit cell has dimensions a=9.584, b=9.104, c=28.434 Å, =92°50, space group P2 ₁/n, and contains 4 molecules. R=0.077 (computed on the 2861 observed independent reflections only).

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Zusammenfassung Die Kristallstruktur von [C₆H₅CH₂N(CH₃)₃]₂CuCl₄ wird bestimmt, wobei die aus spektroskopischen Studien vorgeschlagene Struktur des Ions [CuCl₄]^2– bestätigt wird (gestauchtes Tetraeder der Symmetrie D _2d). Ferner wird gezeigt, daß die S ₄ Achsen der vier [CuCl₄]^2–. Ionen in der Einheitszelle praktisch parallel sind; diese Tatsache erwies sich als sehr wichtig bei der Messung und Auswertung des Spektrums. Die Einheitszelle hat die Dimensionen a=9.584, b=9.104, c=28.434 Å, =92°50, Raumgruppe P2 ₁/n, und enthält vier Moleküle. R=0.077 (nur mit Hilfe der 2861 unabhängigen Reflexionen berechnet).

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Résumé La structure cristalline du tetrachlorocuprate (II) de bis-trimethylbenzylammonium a été déterminée. La structure de l'ion [CuCl₄]^2– proposée dans l'étude spectroscopique, c.a. d'un tétraèdre plat de symétrie D _2d, a été confirmée. On a montré, de plus, que les quatre axes S ₄ des quatre ions [CuCl₄]^2– dans la maille élémentaire sont pratiquement parallèles, car ils sont presque parallèles aux plans de symétrie de glissement, fait qui s'avère de grande importance pour l'accumulation et la mise au point des données spectrales. La maille élémentaire a pour dimensions a=9.584, b=9.104, c=28.434 Å, =92°50, groupe d'espace P2 ₁/n, et contient quatre molécules. R=0.077 (calculé à l'aide seulement de 2861 réflexions indépendantes observées).

     

The crystal structure of (dimorpholinophosphoryl)carbonitrile oxide

An X-ray diffraction study of (dimorpholinophosphoryl)carbonitrile oxide (1) was carried out. The structure of the nitrile oxide group in compound1 is more similar to that in fulminic acid (HCNO) than to those in aryl- and hetarylcarbonitrile oxides. The NO bond in1 is shorter than those in the latter compounds, and the nitrile oxide fragment is more linear due to an increase in the XCN angle.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1245–1247, July, 1994.This work has been financially supported by the Russian Foundation for Basic Research, project No. 93-03-5069.     

The crystal structure of tetraethylammonium aquatetracyanooxorhenate(V)

Summary The crystal structure of the tetraethylammonium salt of [ReO(H₂O)(CN)₄]^– has been determined from threedimensional x-ray diffraction data. The light blue crystals are monoclinic, space group P2₁/m witha=8.760(1),b=9.518(5),c=11.718(1) Å, =102.63(1)^o with two molecules per unit cell. The final R value using 2009 observed reflections and anisotropic thermal parameters for all the non-hydrogen atoms was 0.038. The [ReO(H₂O)(CN)₄]^– ion has a distorted octahedral geometry with the rhenium atom displaced by 0.30 Å out of the plane formed by the four carbon atoms of the cyano ligands towards the oxo ligand. Bond distances: Re=O=1.667(8), Re–OH₂=2.142(7) and Re–C (average)=2.11(1) Å.     

The crystal structure of tetraphenylphosphonium tetracyanohydroxooxorhenium(V)

Summary The crystal structure of (PPh₄)₂[ReO(OH)(CN)₄]·5H₂O has been determined from three-dimensional x-ray diffraction data. The light brown crystals are monoclinic, space group P2₁/n, with cell dimensionsa=16.753(2),b=19.928(2),c=15.338(2) Å and =101,894(1)°,z=4, D_m=1.45(1) g cm^–3. The anisotropic refinement of the 6088 observed reflections converged to R=0.077.The [ReO(OH)(CN)₄]^2– ion has a distorted octahedral geometry. Bond distances: Re =1.70(1), Re–OH=1.90(1) and ReC_av=2.12(2) Å. The Re atom is displaced by 0.08 Å out of the plane formed by the four carbon atoms towards the terminal oxo ligand.     

The crystal structure of Thorium(IV)tetrakis(trifluoroacetylacetonate)

The crystal structure of the compound thorium(IV)tetrakis(trifluoro-acetylacetonate) was determined by means of a threedimensional X-ray analysis. The space group is C2/c and the cell dimensions are a = 25,05 Å, b = 6.43 Å, c = 21.3 Å, β = 125.4°, with Z = 4. The thorium atom is coordinated by 8 oxygen atoms in the form of an 1111 (D₄–422) antiprism. The mean of the Th–O distances is 2.39 Å with a standard deviation ± 0.04 Å. The trifluoroacetylacetonate rings are approximately planar, except for the CH₃ and CF₃ groups which show significant deviations. The Th–O bonds form angles of approximately 72° and 50° with the theoretical 8 -axis of the antiprism. The structure is stabilized by VAN DER WAALS contacts between neighbouring molecules. The refinement of the atomic positions, the anisotropic temperature parameter of thorium and isotropic temperature parameters of all the other atoms by the least squares method, has given a reliability index of 0.148.     

The crystal structure of tetrabutylammonium trichlorocarbonylplatinate(II)

Crystals of [C₁₆H₃₆N]⁺[Cl₃COPt]^? are monoclinic, space group P2₁/n, with a 14.949(8), b 8.892(7), c 18.232(10) Å, β 105.5(3)°, Z 4. The structure has been refined by least-squares to a final R of 0.042 for 2358 counter intensities. The PtCl bond lengths in the square-planar anion are not significantly different (mean value 2.291 Å) and the PtC (carbonyl) bond length is 1.82 Å.Conclusions are drawn on the factors affecting the trans influence in this complex and a number of related square planar Pt^II chloro-complexes.     

The crystal structure of poly(tetramethylene terephthalate)

The unit cell of poly(tetramethylene terephthalate) is triclinic with parameters a = 5.96 Å, b = 4.83 Å, c (fiber axis) = 11.62 Å, α = 115.2. β = 99.9, and γ = 111.3°; space group P1 , calculated crystalline density 1.41 g/cc. The plane of the benzene ring is found to be inclined by about 15° from the fiber axis, contributing to a shortening of the fiber period as compared to the period expected on the basis of analogy with other members of the terephthalate ester series. The remaining shortening of the fiber period occurs in the ? O? °CH₂? °CH₂? segment of the chain. No abnormally short distances among neighboring chain atoms were observed. A typical texture pattern was found in specimens of this polymer that were cold rolled and subsequently annealed. In this texture the c axis of the unit cell is highly oriented in the rolling direction; the a and b axes of the unit cell are oriented preferentially so that the terephthalate residue lies as close as possible to the plane of rolling.     

The crystal structure of bis(trimethyltin)carbonate

The crystal structure of bis(trimethyltin)carbonate, (Me₃Sn)₂CO₃ shows the presence of different tin-atom sites in a polymeric structure which arises as a result of a tridentate mode of coordination of the carbonate dianion.     

The crystal structure of tetrachloro(diethylphthalate)titanium(IV)

The crystal structure of [C₆H₄(OCOC₂H₅)₂TiCl₄], which in the presence of activators is a good catalyst for olefin polymerization, has been determined by X-ray diffraction methods and refined by full-matrix least-squares techniques to R = 0.045 for 2000 independent non-zero reflexions. Crystals are orthorhombic, space group Pnma, with four molecules in a cell of dimensions: a 11.45(1), b 14.07(1), c 10.56(1) Å. The structure consists of discrete molecules possessing crystallographic m (C_s) point symmetry. The Ti atoms are octahedrally coordinated by four chlorine atoms and two carbonyl oxygen atoms of diethylphthalate. The chelating ligand atoms together with the titanium atom form a seven-membered ring with the Cl and Ti atoms located above the benzene ring.     

The crystal structure of bromotris(tetracarbonylcobalt)tin(IV)

Crystal of BrSn[Co(CO)₄]₃ are hexagonal, a = 10.20, c = 11.81 å, space group P6₃. The molecule comparises a central tin atom, surrounded tetrahedrally by the bromine atom and three Co(CO)₄ groups. The SnCo bond length is 2.60 å.     

The crystal and molecular structure of (-)-phaseollin

X-ray analysis has defined the molecular structure of (-)-phaseollin C₂₀H₁₈O₄ a pterocarpan with lipophilic antifungal activity, isolated from Phaseolus vulgaris L. The orthohombic crystals belong to the space group P2₁2₁2₁ with a =6.540(3), b = 12.975(6), c = 19.388(4) Å and Z =4. The structure was solved by direct methods from diffractometer data measured with CuKα radiation, and refined to a final R index of 0.083 for the 992 observed terms. The molecular skeleton(I) has a cis B/C ring junction. Viewed down C(6B)-C(7) the conformation is staggered; ring C is envelope whereas ring B is skewed with C(6B) and C(7) lying respectively above and below the plane of the other ring atoms.