The crystal and molecular structure of lead(II)bromide-bis-dimethylsulphoxide, PbBr2•2[(CH3)2SO]

1977 ◽  
Vol 55 (5) ◽  
pp. 849-855 ◽  
Author(s):  
Anthony D. Baranyi ◽  
Mario Onyszchuk ◽  
Yvon Le Page ◽  
Gabrielle Donnay

The title compound has two PbBr2•2[(CH3)2SO] units, Z = 2, in a cell with a = 11.093(2), b = 12.382(3), c = 4.540(1) Å, belonging to space group Pmmn. The structure was solved by Patterson functions and was refined by full-matrix least-squares calculations to a final R of 0.054 for 348 observed diffractometer intensities. Passing through the unit cell are two antiparallel, infinite polar chains, each with symmetry mm2, extending along z and interacting with each other by weak van der Waals forces. Lead(II) is six-coordinate with a close, covalent hemisphere consisting of two bromine atoms [Pb—BrIBrII 2.93(1) Å], and two oxygen atoms [Pb—O,O′ 2.50(3) Å] which subtend an angle of 157.9(9)° at lead, located at the intersection of the O—Pb—O′ and BrI—Pb—BrII perpendicular mirror planes. The other hemisphere consists of bridging bromine atoms from the neighboring PbBr2•2dmso unit [Pb—BrIII,BrIV 3.24(1) Å], resulting in a rectangle of bromine atoms around lead [BrI—Pb—BrII 90.5(1)°, BrIII—Pb—BrIV 80.2(1)°]. The distortion of the octahedral coordination sphere around lead is discussed in terms of (a) a repulsive effect of the Pb(II) valence lone electron-pair, (b) weak Br—S bonding, and (c) crystal packing forces.

1978 ◽  
Vol 56 (7) ◽  
pp. 891-895 ◽  
Author(s):  
Frederick W. B. Einstein ◽  
Derek Sutton ◽  
Peter L. Vogel

The title compound crystallizes in the space group P21/c with four formula units in a cell of dimensions a = 10.146(6) Å, b = 10.593(4) Å, c = 26.31(1) Å, β = 103.14(3)°. Using 1496 observed reflections (I = 2.3σ(I)) in the range 0° < 2θ < 40° measured on a Picker FACS-1 automatic diffractometer with Mo-Kα radiation, the structure was solved (symbolic addition) and refined (full-matrix least-squares procedure) to R = 0.062 (Rw = 0.058), with all hydrogen atoms included and all non-hydrogen atoms having anisotropic thermal parameters. The dimensions within the cation are consistent with a delocalized electronic structure which is intermediate between valence formulations involving benzenoid or quinonoid structures for the (4-diethylaminophenyl)diazenyl residue. Some important bond lengths are N3—C22 1.336(7) Å, N2—C19 1.356(7) Å, N1—N2 1.308(6) Å, and P—N1 1.648(5) Å.


1982 ◽  
Vol 60 (16) ◽  
pp. 2075-2081 ◽  
Author(s):  
Peter H. Bird ◽  
Upali Siriwardane ◽  
Rabin D. Lai ◽  
Alan Shaver

Fusion invacuo of complexes of the type P2Pt(SR)2 is a facile route to dimers of the type [PPt(SR)(μ-SR)]2; thus, the compounds cis-P2Pt(SR)2, where P = PPh3, PMePh2, R = CH2Ph and trans-P2Pt(SR)2, where P = PPh3, PMePh2, PMe2Ph, R = 4-C6H4CH3 gave the appropriate dimers 1–5. A three-dimensional X-ray structure analysis of the complex [(PMePh2)Pt(SCH2Ph)(μ-SCH2Ph)]2, 2, has shown that it has cis geometry with the benzyl groups of the bridging thiolato ligands oriented anti with respect to each other. The dihedral angle between the two square planes is 138.8°. Crystals of 2 are triclinic, space group [Formula: see text], with two molecules in a cell of dimensions a = 10.856(3) Å, b = 19.935(5) Å, c = 12.202(4) Å, α = 82.52(2)°, β = 105.18(2)°, and γ = 92.35(2)°. Full-matrix least-squares refinement converged at R = 0.052.


1973 ◽  
Vol 51 (22) ◽  
pp. 3691-3696 ◽  
Author(s):  
James C. Barrick ◽  
Crispin Calvo ◽  
Fredric P. Olsen

The structure of the title compound has been determined. Crystals are monoclinic with space group P21/a, Z = 4, a = 13.83(1), b = 19.66(2), c = 5.983(5) Å, β = 101.4(1)°, dcalcd = 1.404, dobs = 1.40(1). A full-matrix least-squares refinement on 1085 unique reflections of positive intensity measure produced a conventional R of 0.066. The spiral arrangement of the S4 chains (nearly generating a 31 axis) is such that the two aromatic rings are eclipsed. Alternation in bond length along the sulfur chain was observed, the long inner bond being 2.083(4) Å and the shorter outer bonds averaging 2.026(3) Å in length. No intermolecular non-bonding interactions involving sulfur were found.


1978 ◽  
Vol 56 (2) ◽  
pp. 179-188 ◽  
Author(s):  
Colin James Lyne Lock ◽  
Graham Turner

The crystal structure of µ-oxobis(cis-dichloro-cis-di(pyridine)-trans-oxorhenium(V)), ORe(C5H5N)2Cl2•O•Re(C5H5N)2Cl2O bas been studied by single crystal X-ray methods. The crystals were orthorhombic with lattice parameters a = 15.367(2), b = 10.283(2), c = 16.685(2) Å. The space group was Pna21 and there were four formula weights per unit cell. A total of 3339 reflections, of which 2990 were observed, were examined, and the structure refined by full matrix least squares (treating the pyridine rings as groups) to an R2 value of 0.0449. The dimer had a roughly rectilinear O—Re—O—Re—O backbone with pairs of chlorine atoms and pyridine molecules arranged cis in each half of the dimer. The two halves of the dimer were arranged such that the pairs of cis atoms in one half were rotated about the Re(1)–Re(2) axis almost 113 ° when compared to the corresponding pair in the other half. Important bond lengths (Re—O(terminal), 1.715(16), 1.764(16); Re—O(bridging), 1.943(16), 1.903(16); Re—Cl, 2.356(5)–2.390(5); Re—N, 2.116(16)–2.180(16)) were close to previously observed values. The molecule was markedly disturbed from the idealized structure and this was caused by intramolecular non-bonded interactions.


1974 ◽  
Vol 52 (19) ◽  
pp. 3331-3336 ◽  
Author(s):  
Anthony Mercer ◽  
James Trotter

Crystals of the title compound, Me2AsC(CF3):C(CF3)AsMe2WI2(CO)3, are monoclinic, a = 15.37(2), b = 9.529(1), c = 15.967(3) Å, β = 112.03(2)°, Z = 4, space group P21/c. The structure was determined by Patterson and Fourier syntheses and refined by full-matrix least-squares procedures to a final R of 0.069 for 1823 observed (of a total of 2778) reflexions. The tungsten atom is seven-coordinate with a distorted capped octahedral environment, the capping group being a carbonyl (W—C, 1.94(3) Å). The capped face consists of the two remaining carbonyl groups (W—C, 1.97(4) and 2.00(4) Å) and one of the arsenic atoms from the bidentate ligand (W—As, 2.556(3) Å). The uncapped face contains the two iodine atoms (W—I, 2.848(2) and 2.856(2) Å) and the remaining arsenic atom (W—As, 2.618(3) Å), this bond length (trans to CO), being significantly longer (by 0.062 Å) than the other (trans to I) W—As distance.


1973 ◽  
Vol 51 (8) ◽  
pp. 1295-1302 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter

Crystals of the title compound are monoclinic, a = 15.539(4), b = 9.061(1), c = 16.707(6) Å, β = 107.19(5)°, Z = 4, space group P21/c. The measured and calculated densities are 1.19 and 1.180(1) g cm−3, respectively. The structure was determined by direct methods and refined by electron-density and full-matrix least-squares procedures to R = 0.047 for 2503 observed reflections. The six-membered phosphazene ring is slightly, but significantly, non-planar, the conformation being that of a distorted boat. The molecule has approximate D3 symmetry. The ring P—N bonds are all equal, mean P—N = 1.588(3) Å, and the relatively short exocyclic P—N bonds, mean 1.652(4) Å, indicate the presence of exocyclic π-bonding in the molecule. The N—C bonds range from 1.417(7) to 1.471(5) with a mean of 1.45(2) Å. The mean endocyclic N—P—N and P—N—P angles are 116.7(4) and 123.0(4)°, respectively, while the exocyclic N—P—N angles average 101.5(8)°.


1984 ◽  
Vol 62 (5) ◽  
pp. 845-855 ◽  
Author(s):  
W. Kliegel ◽  
D. Nanninga ◽  
Steven J. Rettig ◽  
James Trotter

The title compound was prepared by the reaction of 8-methyl-6,6-diphenyl-5,7-dioxa-8-azonia-6-borata-6,7-dihydro-5H-benzocycloheptene (1) with phenylboronic acid. Crystals of 3a-methyl-2,4,9a-triphenyl-1,2,3a,4,9,9a-hexahydro-1,3,9-trioxa-3a-azonia-2-bora-9a-boratacyclopenta[b]naphthalene are monoclinic, a = 11.8548(4), b = 22.7837(4), c = 8.5457(3) Å, β = 106.952(2)°, Z = 4, space group P21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.040 and Rw = 0.047 for 2970 reflections with I ≥ 3σ(I). The molecule was found to be a formal addition product between 1 and PhBO which had undergone a 1,4-shift of a phenyl group from boron to carbon. The backbone of the molecule consists of a folded system of three fused rings. The structure contains the longest known B(sp3)—N(sp3) bond, 1.759(2) Å.


1973 ◽  
Vol 51 (8) ◽  
pp. 1288-1294 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter

Crystals of the title compound are monoclinic, a = 13.840(1), b = 8.9169(5), c = 10.170(1) Å, β = 98.85(1)°, Z = 4, space group P21/n. The structure was determined by direct methods, and refined by electron-density and full-matrix least-squares procedures to R 0.041 for 1458 observed reflections. The five-membered boroxazolidine ring is in the half-chair conformation. Bond angles in the ring range from 99.7° for OBN to 110.1° for BOC. Bond lengths are as follows: mean B—C, 1.611(2), B—N, 1.653(3), B—O, 1.484(3), C—N, 1.485(3), C—O, 1.413(3), mean C—C (aromatic), 1.383(11), and C—C, 1.505(4) Å. The structure consists of discrete molecules linked by O…H—N hydrogen bonds (2.874(2) Å) to form continuous spirals about the 21 axes.


Author(s):  
M. Bidya Sagar ◽  
K. Ravikumar ◽  
Y. S. Sadanandam

AbstractThe crystal structures of two dihydropyridines were solved by direct methods and refined by full-matrix least-squares procedure. 2,6-Dimethyl-3,5-di[N-methyl]-carbamoyl-4-[3,4-methoxy]phenyl-1,4-dihydropyridine hemihydrate, CBoth compounds crystallize with two molecules in the asymmetric unit. In compound


1977 ◽  
Vol 55 (2) ◽  
pp. 333-339 ◽  
Author(s):  
Colin James Lyne Lock ◽  
Graham Turner

The crystal and molecular structure of the title compound has been examined by single crystal X-ray diffraction. The crystals are monoclinic with a = 28.045(10), b = 8.766(3), c = 12.376(5) Å, β = 91.14(3)°. The space group is C2/c and there are eight molecules per unit cell. A total of 5053 independent reflections, of which 2860 were observed, were examined on a Syntex [Formula: see text] diffractometer. The structure was refined by full matrix least squares to an R2 value of 0.0449. The ligands form a very rough octahedron around the rhenium atom with Re—Cl(1), 2.441(3); Re—Cl(2), 2.366(3), Re—O(1), 1.684(7); Re—O(2), 1.896(6); Re—N(1), 2.144(7); Re—N(2), 2.132(7) Å. The pyridine rings are a dominant factor in determining the details of the molecular structure.


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