scholarly journals Notizen: PPh3Me[O8(NO)Cl4]; ein fünffach koordinierter Osmiumnitrosylkomplex / PPh3Me[Os(NO)Cl4]; a Pcnta Coordinate Osmium Nitrosyl Complex

1983 ◽  
Vol 38 (8) ◽  
pp. 1031-1033 ◽  
Author(s):  
Bernhard Czeska ◽  
Kurt Dehnicke ◽  
Dieter Fenske

PPh3Me[Os(NO)Cl4] is prepared by the reac­tion of (NO)2[Os(NO)Cl5] with methyltriphenylphosphonium chloride in CH2Cl2 solution. The complex forms brown, air stable crystals, which are characterized by the IR spectrum as well as by an X-ray structure determination (space group P1̄, two formula units per unit cell, a = 906, b = 1172, c = 1198 pm, α = 76.4, β = 84.8, γ = 82.4°, 3254 independent reflexi­ons, Rw = 8.6%). The structure consists of [P(C6H5)3CH3]⊕ cations and disordered [Os-(NO)Cl4]⊖ anions; the latter have approximate C4V symmetry with a linearly coordinated nitrosyl ligand in the axial position.

1993 ◽  
Vol 48 (7) ◽  
pp. 1009-1012 ◽  
Author(s):  
Kurt Merzweiler ◽  
Harald Kraus

[{Cp(CO)2Fe}SnCl3] reacts with Na2Se in THF to form the compound [{Cp(CO)2Fe}3ClSn3Se4] 1. 1 crystallizes in the monoclinic space group P21/n with 4 formula units per unit cell. The lattice constants are α = 1435.2(7), b = 1124.4(4), c = 1972.7(12) pm, β = 94.59(4)°. According to the X-ray structure determination 1 contains a bicyclic Sn3Se4 framework.


1986 ◽  
Vol 39 (3) ◽  
pp. 541 ◽  
Author(s):  
TCW Mak ◽  
WH Yip ◽  
CHL Kennard ◽  
G Smith ◽  
EJ Oreilly

The crystal structure of anhydrous silver(I)(2-carbamoylphenoxy)acetate has been determined by X-ray diffraction and refined to a residual of 0.041 for 1532 observed reflections. The complex forms crystal: with space group C2/c and Z4 in a unit cell of dimensions a 20.789(6), b 5.202(1) c 17.318(6)Ǻ, β 105.89(2)°. The structure is based on a centrosymmetric bis-carboxylate bridged dimer [Ag-O 2.228(3), 2.266(3)Ǻ, O-Ag-O 155.8(1)°; Ag…Ag 3.001(1)Ǻ] which is extended into an infinite zigzag polymer through the axial positions via the carbamoyl oxygens of adjacent ligands [Ag-O 2.494(3)Ǻ]. Symmetrical long-rang interactions of phenyl-carbon to silver are also found in the structure [Ag-C 3.094, 3.078(4)Ǻ].


1988 ◽  
Vol 43 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Dieter Fenske ◽  
Eberhard Böhm ◽  
Kurt Dehnicke ◽  
Joachim Strähle

Abstract The title compound has been prepared by the reaction of N-trimethylsilyl-iminotriphenylphos-phorane with copper(II) chloride in boiling CCl4 /C2H5OH, and forms moisture sensitive crystals, which are green in transmittance and black in reflexion. [Me3SiNPPh3 · CuCl2 ] 2 was characterized by its IR spectrum as well as by a crystal structure determination (4197 observed, independent reflexions, R = 0.049). The lattice dimensions are at 20 °C: a = 1102.7. b = 1407.3. c = 1560.2 pm; β = 94.27°; space group P21/n with two formula units in the unit cell. The complex consists of centrosymmetric, dimeric molecules with a planar Cu2 Cl2 ring (Cu-CI bond lengths 229 and 231 pm). A terminally bonded CI atom (Cu-CI = 221 pm) and the N atom of the Me3SiNPPh3 ligand (Cu-N = 198.5 pm) complete the coordination number four of the nearly planar surroundings of the Cu atoms.


2014 ◽  
Vol 70 (9) ◽  
pp. 1284-1291 ◽  
Author(s):  
Yann G. J. Sterckx ◽  
Sarah Haesaerts ◽  
Laurence Van Melderen ◽  
Remy Loris

ThepaaR2–paaA2–parE2operon is a three-component toxin–antitoxin module encoded in the genome of the human pathogenEscherichia coliO157. The toxin (ParE2) and antitoxin (PaaA2) interact to form a nontoxic toxin–antitoxin complex. In this paper, the crystallization and preliminary characterization of two variants of the ParE2–PaaA2 toxin–antitoxin complex are described. Selenomethionine-derivative crystals of the full-length ParE2–PaaA2 toxin–antitoxin complex diffracted to 2.8 Å resolution and belonged to space groupP41212 (orP43212), with unit-cell parametersa=b= 90.5,c= 412.3 Å. It was previously reported that the full-length ParE2–PaaA2 toxin–antitoxin complex forms a higher-order oligomer. In contrast, ParE2 and PaaA213–63, a truncated form of PaaA2 in which the first 12 N-terminal residues of the antitoxin have been deleted, form a heterodimer as shown by analytical gel filtration, dynamic light scattering and small-angle X-ray scattering. Crystals of the PaaA213–63–ParE2 complex diffracted to 2.7 Å resolution and belonged to space groupP6122 (orP6522), with unit-cell parametersa=b= 91.6,c= 185.6 Å.


2017 ◽  
Vol 32 (S1) ◽  
pp. S2-S5 ◽  
Author(s):  
Jacek Podwórny ◽  
Alicja Pawełek ◽  
Jerzy Czechowski

Having synthesised an AlON-bonded ceramic corundum material, Al5O3N3 (15R) polytype coexisting with α-Al2O3 was identified. The sample was prepared from an alumina-rich mixture of Al2O3 and AlN substrates and fired at 1650 °C in a nitrogen atmosphere. Using the X-ray external standard quantitative method, one of the reaction products, α-Al2O3, was quantified. From the remaining substrates the stoichiometric composition of the second phase was calculated. The applied method of crystal structure determination consisted of three stages. In the first stage, the Le Bail method of X-ray pattern decomposition was used for the extraction of Al5O3N3 (15R) diffraction lines from a two-phase diffractogram. The space group and unit-cell dimensions from the isostructural SiAl4O2N4 SiAlON phase, producing the same X-ray pattern, were used as input data. Next, the direct structure determination in real space was applied for initial structural model derivation, which was followed by Rietveld refinement. The solved crystal structure of Al5O3N3 (15R), except the stacking sequence, proved to be closely related to the structure of Al7O3N5 (21R) polytype. The Al5O3N3 (15R) is trigonal with space group R-3m, unit-cell dimensions a0 = 3.0128 Å, c0 = 41.8544 Å, and volume V = 329.00 Å3. The model of Al5O3N3 (15R) polytype structure has positional disordering in one of three (6c) Al sites, which leads to stacking faults in six tetrahedral layers. Every third tetrahedron from LR3 and LR4, LR8 and LR9, LR13 and LR14 layers is rotated by 180°.


1994 ◽  
Vol 49 (3) ◽  
pp. 430-433 ◽  
Author(s):  
Hans-Dieter Hausen ◽  
Jochen Tödtmann ◽  
Johann Weidlein

AbstractN-M ethyl-2-dimethylaluminium pyrrolide, (CH3)2Al -C4H3NCH3, crystallizes in the triclinic space group P1̄ with the lattice constants a = 700.5(1), b = 725.9(1), c = 886.8(1) pm, α = 67.69(1)°, β = 70.99(1)°, γ = 88.48(1)°, and Z = 2. This compound is isotypic with the gallium homologue [1], the shortest metal-ring contact between the two molecules of one unit cell decreases to 228.6 pm. N-dimethylgallium tetramethylpyrrolide has been synthesized from Li-N (CCH3)4 and (CH3)2GaCl. This “π-associate” crystallizes in the monoclinic space group P21/c with the lattice parameters a = 989.9(2), b = 1305.4(3), c = 878.3(2) pm, β - 112.73(1)° and 4 units per cell. Again two centrosymmetrically orientated molecules form a dimer by short (224.0 pm) intermolecular “Ga - πC ” contacts but the structure differs significant from the structure of the indium homologue [1].


1988 ◽  
Vol 43 (2) ◽  
pp. 135-137 ◽  
Author(s):  
H.-Jürgen Meyer ◽  
Joachim Pickardt

Ca2[Fe(CN)6] · C6H12N4 · 6H2O crystallizes in the monoclinic space group B2/b with a = 1130,2(4), b = 1373,5(4), c = 1353,0(4) pm and γ = 97,17°. The X-ray single crystal structure determination converged at R = 0.055 (2057 reflections). Each of the four Fe(CN)6 octahedra (Z = 4) in the unit cell is coordinated by six Ca atoms with mean NCYAN - Ca distances of 253.5(3) pm. The Ca atoms are bridged by hexamethylenetetramine and water molecules


1989 ◽  
Vol 44 (3) ◽  
pp. 370-372 ◽  
Author(s):  
Ute Patt-Siebel ◽  
Ulrich Müller ◽  
Petra Klinzing ◽  
Kurt Dehnicke

Di-trichloroacetimide, HN(COCCl3)2. was prepared by the reaction of trichloroacetic acid with trithiazylchloride at 60 °C. The compound was characterized by its IR spectrum as well as by an X-ray structure determination: Space group P 1, Z = 2, 1662 observed independent reflexions, R = 0.034. Lattice dimensions at 17 °C: a = 640.9(2); b = 924.1(3); c = 943.0(2) pm; α = 92.11(2)°; β = 106.53(3)°; γ = 99.02(3)°. The compound forms the Z,Z(trans-trans)isomer. There is no intermolecular hydrogen-bonding.


1990 ◽  
Vol 55 (8) ◽  
pp. 2046-2051 ◽  
Author(s):  
Jiří Novotný ◽  
Jan Ondráček ◽  
Vladimír Stružka ◽  
Bohumil Kratochvíl

The structure of 1,4-dimethyl-3,6-diphenyl-2,5,7-trioxabicyclo[2,2,1]heptane was solved by direct methods and anisotropically refined to a final R value 0.023 for 648 observed reflections (I > 3σ(I)) and 133 refined parameters. The symmetry of the structure corresponds to the P21212 space group with lattice parameters a = 16.857(2), b = 8.756(1), c = 5.245(1) Å. The unit cell contains two formula units. The molecule under study possesses twofold rotation axis, which passes through the O2 atom. The molecular structure found from X-ray data corresponds to 1H and 13C NMR spectroscopic results. Further IR spectrum and optical rotation value are included.


1991 ◽  
Vol 46 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Evamarie Hey-Hawkins ◽  
Hans Georg von Schnering

NaSi reacts with MoCl5 and 15-crown-5 in toluene with reduction of Mo(V) to Mo(IV). Work-up in DME yields MoCl4(DME)· 15-crown-5 (1). MoCl4(DME) (2) is prepared more conveniently from MoCl5/DME. 1 and 2 were characterized spectroscopically and by X-ray structure determination. Crystal data: 1, space group P212121 (No. 19), Z = 4, 2765 observed independent reflexions, R = 0.026, cell dimensions (110 K): a = 16.292(4), b = 12.884(3), c = 10.452(2) Å. 2, space group I4̄2d (No. 122), Z = 8, 558 observed independent reflexions, R = 0.037, cell dimensions (292 K): a = b = 9.562(2), c = 23.777(6)Å. The MoCl4(DME) molecule of 1 and 2 forms a distorted octahedron. There are four non-coordinating 15-crown-5 molecules present in the unit cell of 1. The UV/VIS spectrum and the magnetic properties of 2 are discussed.


Sign in / Sign up

Export Citation Format

Share Document