K. Ann Kerr

Three dimensional structure of adenosine triphosphate.

The three dimensional structure of adenosine triphosphate in the hydrated disodium salt is reported to a resolution of 0.9 Å.

The Crystal and Molecular Structure of Quaterrylene: A Redetermination

The crystal structure of quaterrylene, C40H 20-first studied with limited two dimensional X-ray data in 1960 - has been redetermined with three dimensional data. Some 2816 independent reflexions have been measured. Fullmatrix least-squares refinement with large matrices of up to 200 parameters has reduced Rto 4.00 % for the 1162 reflexions with intensities significantly above background and 11.04% for the total data set. Carbon atom positions were refined anisotropically and C-C distances have been determined with an estimated standard deviation of ±0.004 A. The average length of the six pen-bonds is 1.465(5) Å . These can be divided into two chemically equivalent sets with an average length of 1.467(3) Å for the four outer bonds and 1.462(6) Å for the central pair. The crystal contains dimers consisting of two centro-symmetrically related molecules separated by a mean perpendicular distance of 3.41 Å . This is smaller than the corresponding separation in a-perylene, and approaches the interlayer spacing in graphite. There are small, significant deviations from planarity in the quaterrylene molecule at least some of which seem to be related to the interactions between the two molecules of the dimer.

Synthetic, structural, and spectroscopic studies of the ligating properties of organic disulphides: X-ray structure of copper(I) iodide–diethyl disulphide (2/1)

The synthesis of a series of derivatives of copper(I) halides with organic disulphides is reported. Although most of these complexes are unstable with respect to loss of ligand, the compound 2Cul·Et2S2 was sufficiently stable to be subjected to a single-crystal X-ray structure determination. Crystals are monoclinic, space group P21/n, with cell dimensions (at –100 ± 5 °C)a= 8.163(4), b= 15.651(3), c= 8.746(4)A, β= 100.73(2)°, and Z= 4. The structure was solved with data collected at –100(5)°C using direct methods followed by difference-Fourier techniques, and refined to R 0.038 (R′ 0.047) for 1 157 observed reflections. The structure consists of double chains of copper atoms bridged by two iodines, with alternative pairs of copper atoms also bridged by diethyl disulphide molecules. The geometry of the disulphide is compared with that of related complexes, and Raman spectral studies of the ν(S–S) stretching frequency of the series of complexes are reported.

Crystal and molecular structure of 1,1′-binaphthyl

The crystal structure of 1,1′-binaphthyl has been determined by X-ray analysis. The crystals are monoclinic space group C2/c, with a= 20·98, b= 6·35, c= 10·13 A, β= 105·17°; Z= 4. The molecule exists in a cis-configuration with an angle of 68° between the planes of the two naphthalene residues, the dimensions of which are not significantly different from those of naphthalene itself. The sp2–sp2 single-bond between the two ring systems has a length of 1·475 ± 0·005 A. The final R is 0·085 for 1315 observed reflections.

The alkaloids of nutt.

The structures of alkaloid- and - were established via X-ray crystallography of the former as its HI salt, and its chemical conversion to the latter.Abstract The structures of alkaloid- A and - B were established via X-ray crystallography of the former as its HI salt, and its chemical conversion to the latter.

Tricarbonyl (triquinacene)-molybdenum and-tungsten

Summary Triquinacene reacts with hexacarbonylmolybdenum to give tricarbonyl(triquinacene)molybdenum, and with tris(acetonitrile)tricarbonyltungsten to give tricarbonyl(triquinacene)tungsten, whereas efforts to synthesize the corresponding chromium complex, tricarbonyl(triquinacene)chromium, were unsuccessful. The molybdenum complex was characterized by 1H and 13C NMR spectroscopy, mass spectra, and a single crystal X-ray structure determination. The tungsten complex is thermally less stable and more susceptible to oxidation than its molybdenum analogue and was characterized by the mass spectrum and the 1H NMR spectrum. The crystal structure of the tricarbonyl(triquinacene)molybdenum is compared to that for the free ligand. Besides the expected lengthening of the C=C bonds, the complex shows a deepening of the triquinacene “basket”, presumably to give better overlap of the C=C bonds with molybdenum orbitals.

The structure of delphinifoline, a diterpenoid alkaloid from aconitum delphinifolium

Abstract The structure of delphinifoline, a minor alkaloid of Aconitum delphinifolium DC, was established by spectroscopic methods, and X-ray crystallography.

The crystal structure of di-µ-ethanethiolato-µ-sulphido-bis[dichloro-(tetrahydrothiophen)tungsten(IV)(W–W)]: a confacial bioctahedral complex with a tungsten-to-tungsten bond

The complex [(C4H8S) Cl2W(µ-S)(µ-SEt)2WCl2(SC4H8)] has been prepared by reaction of [WCl4(C4H8S)2] with one mole equivalent of SiMe3(SEt) in CH2Cl2 solution. A single-crystal X-ray diffraction study shows that the molecule has a confacial bioctahedral structure with a W–W bond length of 2.524(1)A. The structure has been solved by heavy-atom methods from automated diffractometer data, and refined to R 0.025 (R′ 0.037) for 1 593 reflections. The complex crystallizes in the orthorhombic system, space group Pnam, with a= 10.592(3), b= 12.618(4), c= 17.430(6)A, and Z= 4.

The synthesis and characterization of µ-hydrido-bis-(µ-sulphide)-ditungsten(III) complexes: the X-ray crystal structure of [HPPh3][Cl3W(µ-H)(µ-Me2S)2WCl3]

The reaction of WCl4(Me2S)2 with Et3SiH yields Cl3W(µ-H)(µ-Me2S)2WCl2(Me2S) from which the anion [Cl3W(µ-H)(µ-Me2S)2WCl3]– can be prepared; a single-crystal X-ray diffraction study of [HPPh3][Cl3W(µ-H)-(µ-Me2S)2WCl3] shows that these complexes possess a confacial bioctahedral framework with a formal W–W triple bond of length 2·410(7)A.

The crystal structure of triphenylarsine sulphide

Crystals of AsPh3S obtained from acetone solution are monoclinic, space group P21/c, Z= 8, with unit-cell dimensions a= 18.523(8), b= 9.642(4), c= 18.140(8)A, and β= 105.93(4)°. The compound is isomorphous with PPh3S and PPh3Se. The structure has been elucidated on the basis of this isomorphism, from 2 795 observed reflections and refined to R 0.042 2. The AsS bond is essentially a double bond, and in both molecules of the asymmetric unit one phenyl ring lies almost coplanar with the As–S bond, while the other rings have an average torsion angle of 53°. The molecular structure is compared with those of PPh3S and PPh3Se in an attempt to elucidate the reasons for the observed conformations.