[4-(N,N - Dimethylamino)phenyl]diphenylphosphine Oxide and its Partial Oxides: An Isomorphous Crystal Series

The title compound [4-(N,N-dimethylamino)phenyl]diphenylphosphine oxide (1) has been synthesized and its single-crystal X-ray structure determined. The structures of two 'partial' oxides of the parent compound, (2) and (3) (50% and 25% oxidized), isolated from the intermediate phosphine reaction product have also been determined, yielding an unusual isomorphous crystal series. An apparent P-O bond shortening with increasing oxidation is also observed across the series (1)-(3) (1.480(4), 1.351(4), 1.280(4) Å respectively) and is considered an artifact of the structure refinement. The packing in the crystals shows primary one-dimensional chains with weak head-to-tail associations between the oxide oxygen (three-centre) and two hydrogen atoms from separate methyl groups of the N-substituted amine (range C-H⋯O 3.115(4)-3.356(8) Å), extended into a sheet structure by peripheral inter-chain C-H (aromatic)⋯O (oxide) associations

Insecticides. XIII.† Crystal structure of isobenzan (exo-1, exo-3,4,5,6,7,8,8-Octachloro-1,3,3a,4,7,7a-hexahydro-endo-4,7-methanoisobenzofuran)

The crystal structure of isobenzan was determined by direct methods. The crystals are monoclinic, (C2/c) with Z = 16, in a cell of dimensions a = 2571(1), b = 1735(2), c = 1361(1) pm; β = 100.65(1)°. The structure was refined by least squares to R 0.073 with 1650 unique reflections collected on an automated equi-inclination diffractometer. The two molecules (A, B) of isobenzan in the asymmetric unit are similar and possess the exo-1, exo-3-chlorine arrangement and the endo tetrahydrofuran configuration, previously proposed on the basis of chemical evidence. This results in the molecules possessing approximate C(m) point symmetry with the bridgehead carbon and its attached chlorines, and the epoxide oxygen lying in the mirror plane. There is no evidence of intermolecular association involving oxygen or chlorine

Simple densitometer for X-ray powder photographs

A simple microprocessor-controlled microdensitometer has been built which is able to step scan an X-ray powder diffraction Guinier film to produce intensity data which are subsequently written to a floppy disk for further processing. The densitometer is based on a modification of a local Apple II controlling a two-circle diffractometer (Kennard, Calos, Spatny & Jankovits, 1988), with the existing 2θ-arm motor drive, interface, software and a digital output line being used with modification. A light source and detector replaces the scintillation counter on the arm, and the film to be scanned held in a semicircular translatable canister, with three viewing slits for the three patterns obtained from an Enraf-Nonius FR 552 Guinier camera. The light source, a LED, emitting visible wavelength (700 nm), may be focused through a lens system, improving resolution of the instrument, by magnifying the film

Use of a Hewlett-Packard ScanJet- image digitizer as an X-ray powder photograph densitometer

A densitometer trace of an X-ray powder photograph is easily obtained by making a contact print and scanning this with a Hewlett-Packard ScanJet using the programs SCANGAL, IMAGE EDITOR and SCANNER on SCANNING GALLERY in the WINDOWS environment. The light in the ScanJet from a halogen lamp (50 V, 42.5 W) is reflected by the print and detected by a charge-coupled device. The instrument measures reflected light intensity. The flatbed ScanJet has an optical resolution of 2550 dots yielding 300 dots per inch (d.p.i.) over the A4 page. Output resolution is selectable and runs from 38 to 600 d.p.i. The density and mode (binary, dithered, greyscale and scaling) may be adjusted. However, when scanned, the regular negative Guinier photograph does not give clear images because the rough developed-emulsion surface scatters light indiscriminately, producing dark images and lacking in resolution

Endothermic changes in K<inf>2</inf>PbCu(NO<inf>2</inf>)<inf>6</inf> at 279 and 287 K

Two endothermic changes of 90 cal mol-1 were observed in K 2PbCu(NO2)6 at 279 and 287 K using a differential scanning calorimeter and the transition at 279 K was confirmed by e.s.r. spectra

Metal-phenoxyalkanoic acid interactions. Part 14. The crystal and molecular structures of diaquabis(4-fluorophenoxyacetato)copper(II) bis(4-fluorophenoxyacetic acid)dihydrate and tetra-μ-(4-fluorophenoxyacetato-0,0′)-bis[(2-aminopyrimidine)copper(II)]

The crystal structures of two copper(II) complexes of 4-fluorophenoxyacetic acid (4-FPAH) have been determined by X-ray diffraction. [Cu(4-FPA)(HO)]·2(4-FPAH)·2HO (1) is triclinic, space group P1 with Z = 1 in a cell of dimensions a = 14.808(2), b = 9.832(2), c = 6.847(2) Å, α = 87.77(2), β = 98.41(2), γ = 112.33(2)° and was refined to a residual of 0.038 for 1697 'observed' reflections. The coordination sphere in this complex is tetragonally distorted octahedral comprising two waters [CuO, 1.940(3) Å], two unidentate carboxylate oxygens [CuO, 1.942(2) Å] and two ether oxygens [CuO, 2.471(2) Å]. Two adducted [4-FPAH] acid molecules are linked to the un-coordinated oxygens of the acid ligands by hydrogen bonds [2.547(4) Å]. [Cu(4-FPA)(2-aminopyrimidine)] (2) is triclinic, space group P1 with Z = 1 in a cell of dimensions a = 12.688(2), b = 11.422(2), c = 7.951(1) Å, α = 78.74(1), β = 107.51(1), γ = 75.78(1)°, and was refined to a residual of 0.042 for 2683 'observed' reflections. (2) is a centrosymmetric tetracarboxylate bridged dimer with four similar CuO (equatorial) distances [1.967-1.987 Å; 1.977(3) Å mean] and the axial position occupied by the hetero nitrogen of the 2-aminopyrimidine ligand [CuN, 2.176(3) Å]. The Cu---Cu separation is 2.710(1) Å. Crystal data are also presented which confirm the isostructurality of complex (2) with [Cu(phenoxyacetate)(2-aminopyrimidine)], the Co, Mg and Mn4-fluorophenoxyacetate complexes with their phenoxyacetic and 4-chlorophenoxyacetic acid analogues, and of Cd4-fluorophenoxyacetate with Cd and Zn phenoxyacetates