scholarly journals ReNF4 · ReF5(NCl), ein Nitrido-Nitrenokomplex von Rhenium(VII)/ ReNF4 · ReF5(NCl), a Nitrido Nitrene Complex of Rhenium (VII)

1984 ◽  
Vol 39 (8) ◽  
pp. 1114-1117 ◽  
Author(s):  
Willi Kafitz ◽  
Kurt Dehnicke ◽  
Eberhard Schweda ◽  
Joachim Strähle

AbstractReNF4 · ReF5(NCl) is prepared by direct fluorination of ReNCl4 with fluorine between 80 °C and 130 °C. The red crystals are extremely sensitive to moisture. The complex is characterized by the IR spectrum and by an X-ray structural investigation. ReNF4 · ReF5(NCl) crystallizes orthorhombically in the space group Pnma with 4 formula units per unit cell and with the cell dimensions a = 1440, b = 848, c = 776 pm (419 observed, independent reflexions, R = 13.9%). The complex consists of the molecules ReNF4 and ReF5(NCl), which are linked by a linear asymmetric fluorine bridge. The bridging fluorine atom is in trans-position to the nitrido ligand Re -F - 228 pm) and to the nitreno ligand (Re -F = 159 pm and Re= N - Cl 164 pm) correspond to triple 188 pm). The Re ≡ N bond lengths Re= N bonds.

1985 ◽  
Vol 40 (8) ◽  
pp. 1005-1009 ◽  
Author(s):  
Thomas Godemeyer ◽  
Kurt Dehnicke ◽  
Dieter Fenske

AbstractThe title compound results from a slow reaction between two m oles of PPh4[W2NCl10], dissolved in dichlorom ethane, upon addition of carbon tetrachloride. The red crystals are characterized by X-ray diffraction. (PPh4)2[W3N2Cl14] · CCl4 · CH2Cl2 crystallizes triclinically in the space group P1̄ with two formula units per unit cell. The cell dimensions at -100 °C are: a = 1430, b = 1462, c = 1655 pm , α = 74.6°, β = 79.0°, γ = 82.4° (10,908 independent, observed reflexions, R = 0.078). The structure consists of PPh4⊕ ions, trinuclear finitrido anions [W3N2Cl14]2⊝ and enclosed molecules of CCl4 and CH2Cl2. The tungsten atom s of the anion are linked by almost linear nitrido bridges (~176°) with different WN bond lengths (mean values 184 pm and 207 pm ), corresponding to double and single bonds. The equatorial WCl4 groups are in eclipsed conformation; the two chlorine atoms in trans-position to the nitrido groups have mean bond lengths of 240 pm which is 9 pm longer than the equatorial W -Cl bonds. The IR spectrum is reported.


1987 ◽  
Vol 42 (8) ◽  
pp. 947-950 ◽  
Author(s):  
Karin Völp ◽  
Frank Weller ◽  
Kurt Dehnicke

Abstract[MoCl4(NPPh3)(pyridine)] · CH2Cl2 is formed by the reaction of the cyclothiazeno complex [MoCl3(N3S2) · (pyridine)] with triphenylphosphane in CH2Cl2 solution. It forms red, moisture sensitive needles. [MoCl4(NPPh3)(C5H5N)] · CH2Cl2 crystallizes monoclinically in the space group P21/n with four formula units per unit cell (1934 independent observed reflexions. R = 0.057). The cell dimensions are a = 1165, b = 1473, c = 1696 pm; β = 107.82°. The Mo atom is coordinated by four chlorine atoms, by the N atom of the (NPPh3-) ligand, and in trans-position to it by the N atom of the pyridine molecule. The Mo= N = PPh3 group has a nearly linear MoNP axis (176.6°) with bond lengths of MoN = 172 pm and PN = 165 pm.


1987 ◽  
Vol 42 (8) ◽  
pp. 943-946 ◽  
Author(s):  
Abderraouf Khabou ◽  
Wolfgang Willing ◽  
Ulrich Müller ◽  
Kurt Dehnicke

AbstractThe donor acceptor complexes WC13(N 3S2)-L (L = TH F, pyridine), and [WCl3(N3S2)]2 · dipy are prepared from WCl3(N3S2) and the corresponding donor molecules. WBr3(N3S2) ­ THF is formed by the reaction of WCl3(N3S2) THF with BrSiMe3. The complexes have been characterized by their IR spectra. The crystal structure of WCl3(N3S2) THF was determ ined by X-ray diffraction. It crystallizes monoclinically in the space group P21/c with four formula units per unit cell (1903 observed, independent reflexions, R = 0.031); the cell dimensions are a = 1072.0. b = 1007.2, c = 1128.9 pm; β = 94.84°. The tungsten atom is a member of a nearly planar WN3S2 ring with WN bond distances of 180 and 184 pm, which correspond to double bonds. The sixfold coordination of the W atom is completed by three chlorine atoms and the O atom of the tetrahydrofuran ligand, which is coordinated in trans-position to one of the N atoms; the THF molecules forms a dihedral angle of 40.1° with the WN3S2 ring.


1976 ◽  
Vol 31 (5) ◽  
pp. 541-543 ◽  
Author(s):  
Helmut Rieskamp ◽  
Rainer Mattes

The crystal structure of [enH2][VOF4(H2O)]2 has been determined from X-ray diffractometer data. Crystals are monoclinic, space group C2/c with Z = 4 in a unit cell of dimensions a = 16.576(13), b = 7.781(4), c = 10.338(8) Å, β = 120.0(1)°.The structure was refined by least-squares methods to R 0.053 for 1436 reflections. The structure contains monomeric [VOF4(H2O)]⁻-ions with the oxygen atoms in trans position. The bond distances are 1.577 Å (terminal oxygen) and 2.333 Å (H2O molecule), resp. The V–F distances vary between 1.769(2) and 1.858(2) Å for fluorine atoms involved in strong hydrogen bonds.


1989 ◽  
Vol 44 (9) ◽  
pp. 1003-1006 ◽  
Author(s):  
Kurt Merzweiler ◽  
Dieter Fenske ◽  
Eva Hartmann ◽  
Kurt Dehnicke

The title compound has been prepared by the reaction of N,N,N′-tris(trimethylsilyl)benzamidine with tantalum pentachloride in CH2Cl2 suspension, forming amber-coloured, moisturesensitive crystals, which were characterized by an X-ray structure determination. Space group P 21/n, Z = 2, 4895 observed independent reflexions, R = 0.059. Lattice dimensions (-65°C): a = 1165.2(6), b = 1335.4(6), c = 1629.0(7) pm, β = 93.23(4)°. The complex forms centrosymmetric molecules dimerized via chloro bridges TaCl2Ta with TaCl bond lengths of 247.2(2) and 277.1(2) pm, the longer one being in trans-position to the imido group, which can be formulatedas [xxx] (bond lengths Ta=Ν = 183.5(8), C=N = 134(1) pm, bond angle TaNC = 162.7(7)°).


1993 ◽  
Vol 48 (7) ◽  
pp. 1019-1022 ◽  
Author(s):  
Gerlinde Frenzen ◽  
Dorothea Wolff von Gudenberg ◽  
Kurt Dehnicke

The crystal structure of [ReCl4(PhC = CPh)(OPCl3)] was solved with X-ray methods. Space group P1̄, Z = 2, 2085 observed unique reflections, R = 0.029. Lattice dimensions at -70°C: a = 857.0(2), b = 937.9(2), c = 1249.6(2) pm, α = 87.43(3)°, β = 83.48(3)°, γ = 89.80(3)°. [ReCl4(PhC ≡ CPh)(OPCl3)] has a molecular structure with the alkyne ligand bonded side-on (bond lengths Re-C 198.9(8) and 198.6(7) pm). The oxygen atom of the solvating POCl3 molecule is coordinated in trans position to the ReC2 unit of the alkyne ligand (bond length Re-O 226.7(5) pm).


1996 ◽  
Vol 49 (7) ◽  
pp. 817 ◽  
Author(s):  
M Sterns ◽  
RL Withers ◽  
P Midgeley ◽  
R Vincent

The preparation, chemical characterization and structural investigation by X-ray and electron diffraction of two uranates (VI), namely Sr5U3O14 and of Pb11U5O26, are reported. The strontium compound, the unit cell of which is metrically tetragonal with a = 11.248(5), c = 11.086(5) Ǻ, Z = 4, was shown by electron diffraction to be orthorhombic, space group Pbca with a = b. Crystals of Sr5U3O14 are invariably submicroscopically twinned and, because of the identity of a and b, mimic tetragonal symmetry. The lead uranate , Pb11U5O26, was shown to be a long-period superstructure with unit cell dimensions a = 44.54, b = 15.586, c = 8.241 Ǻ, Z = 8.


1971 ◽  
Vol 49 (2) ◽  
pp. 167-172 ◽  
Author(s):  
F. Leung ◽  
S. C. Nyburg

The crystal structure of a thiathiophthen nitrogen isostere (7) has been solved by X-ray analysis. The crystal belongs to the triclinic system with unit cell dimensions: a = 11.275(11), b = 9.558(10), c = 10.797(10) Å, α = 92.50(10), β = 116.98(10), γ = 92.61(10)°. There are two molecules per unit cell, space group [Formula: see text]. The data were collected by diffractometer with CuKα radiation. The structure was solved by symbolic addition procedures, and fully refined anisotropically using full-matrix least squares to an R factor of 6.3%.The S—S and S—N bond lengths were found to be 2.364 and 1.887 Å, respectively. This reveals the partial bonding character between S … S … N atoms.


Author(s):  
L. W. Labaw

Crystals of a human γGl immunoglobulin have the external morphology of diamond shaped prisms. X-ray studies have shown them to be monoclinic, space group C2, with 2 molecules per unit cell. The unit cell dimensions are a = 194.1, b = 91.7, c = 51.6Å, 8 = 102°. The relatively large molecular weight of 151,000 and these unit cell dimensions made this a promising crystal to study in the EM.Crystals similar to those used in the x-ray studies were fixed at 5°C for three weeks in a solution of mother liquor containing 5 x 10-5M sodium phosphate, pH 7.0, and 0.03% glutaraldehyde. They were postfixed with 1% osmium tetroxide for 15 min. and embedded in Maraglas the usual way. Sections were cut perpendicular to the three crystallographic axes. Such a section cut with its plane perpendicular to the z direction is shown in Fig. 1.This projection of the crystal in the z direction shows periodicities in at least four different directions but these are only seen clearly by sighting obliquely along the micrograph.


1987 ◽  
Vol 65 (2) ◽  
pp. 261-270 ◽  
Author(s):  
R. A. Bell ◽  
B. E. Brown ◽  
M. Duarte ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock

1,1,3,3-Tetracyanopropane, 1, was prepared in low yields by a literature method with 2,2,4,4,6-pentacyanocyclohexenamine, 2, as a major by-product. The products were examined by X-ray crystallography. 1 has an orthorhombic space group, Pbcn (No. 60) with cell dimensions, a = 7.158(2), b = 10.510(3), c = 9.733(2) Å and has four formula units in the unit cell. 2 has a monoclinic cell, P21/c (No. 14) with cell dimensions a = 14.368(3), b = 6.626(1), c = 12.300(2) Å, β = 115.60(1)° and has 4 formula units in the unit cell. Data were collected with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structures were determined by standard methods and refined to Rw = 0.037 (1) and Rw = 0.040 (2) on the basis of 782 and 2108 unique reflections. Bond lengths and angles in the two compounds are normal. 2 has what has been considered to be the less likely tautomeric structure. Both compounds were examined by 1H, 13C nmr, vibrational spectroscopy, and mass spectroscopy. For 2 there was no evidence of the alternative tautomeric structure. New methods were developed for the preparation of both compounds and the mechanism of the original reaction rationalized.


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