Oxotrihalogenoselenate(IV): Darstellung, Struktur und Eigenschaften von P(C6H5)4SeOCl3, P(C6H5)4SeOBr3 und As(C6H5)4SeOBr3

1982 ◽  
Vol 37 (11) ◽  
pp. 1410-1417 ◽  
Author(s):  
Bernt Krebs ◽  
Andreas Schaffer ◽  
Marita Hucke

The novel oxotribromosolcnate(IV) SeOBr3- anion was prepared from the reaction of stoichiometric quantities of SeOBr2 and bromide in acetonitrile solution, and it was isolated as the tetraphenylphosphonium and -arsonium salts in crystalline form. For the synthesis of the analogous SeOCl3- as P(C6H5)4SeOCl3, SeCl4 was reacted in the presence of a small quantity of H2O with P(C6H5)4Cl in acetonitrile. Complete X-ray structural analyses of P(C6H5)4SeOCl3 (space group P1̄, a = 10.981(3), b = 11.0511(3), c = 10.358(3) Å, α = 73.77(2)°, β = 83.33(2)°, γ = 80.51(2)°, V = 1187.9(6) Å3) and of P(C6H5)4SeOBr3 (space group P 21/c, a = 11.719(4), b = 16.088(4), c = 13.124(4) Å, β = 94.72(3)°, V = 2400(1) Å3) show dimeric centrosymmetric Se2O2Cl62- and Se2O2Br62- anions being present in the solid. In the anions two square-pyramidal (Ψ-octahedral) SeOHal4 groups are connected through a common Hal-Hal edge. The axial oxygen ligands (So-O: 1.597(4) and 1.584(0) Å) cause a pronounced stereochemical trans-activation of the inert pairs at the Se atoms. As(C6H5)4SeOBr3 is isotypic with P(C6H5)4SeOCl3.

1984 ◽  
Vol 39 (12) ◽  
pp. 1633-1641 ◽  
Author(s):  
Bernt Krebs ◽  
Andreas Schäffer ◽  
Siegfried Pohl

The novel anion SeBr42- was prepared by dissociation of SeOBr2 with formation of SeBr2 and subsequent reaction with bromide in acetonitrile solution; it was isolated as the crystalline tetraphenylphosphonium salt. The X-ray structure analysis of [P(C6H 5)4]2SeBr4 (space group P 1̄ , a = 14.190(3), b = 15.125(3), c = 10.383(2) Å , α = 92.69(2), β = 100.89(2), γ = 92.04(2)° Å , V = 2182.2 Å3) shows the structure to contain monomeric SeBr42- anions with a square planar coordination of Se(II). The mean Se -Br bond length in the anion is 2.598 Å .[P(C6H5)4]2Se2Br6 was obtained from the reaction of SeBr4 (which is in equilibrium with SeBr2, Se2Br2, and Br2, in solution) and bromide in acetonitrile. It crystallizes in the space group P 1̄, with a = 1 0 . 9 3 3 ( 4 ) , = 11.154(4), c = 10.344(4) Å , α = 79.26(3), β = 72.63(3), y = 81.35(3)°, γ = 1176.7 Å3 (at -120 °C), and contains a novel type of centrosymmetric Se2Br62- ions with square planar Se-coordination. The mean terminal and bridging Se -Br bond lengths are 2.442 and 2.799 Å , resp. Vibrational spectra are reported and discussed.


1998 ◽  
Vol 54 (4) ◽  
pp. 399-416 ◽  
Author(s):  
S. C. Abrahams ◽  
H. W. Schmalle ◽  
T. Williams ◽  
A. Reller ◽  
F. Lichtenberg ◽  
...  

The possibility that the structure of the novel semiconducting perovskite-related material strontium niobium oxide, Sr5Nb5O17, refined by Schmalle et al. [Acta Cryst. (1995), C51, 1243–1246] in space group Pnn2, might instead belong to space group Pnnm has been investigated following an analysis of the atomic coordinates that indicated the latter space group to be more likely. All I obs were carefully remeasured, first those within a hemisphere containing c *, then all that lay within the full sphere of reflection. Refinement was undertaken, with each of two different sets of weights, in each space group. Each data set was used under three limiting intensity conditions: I obs > 4σ(I obs), I obs > 2σ(I obs) and finally with all reflections, but setting magnitudes with I obs ≤ 0 equal to 0. Fourteen separate tests based only upon the X-ray diffraction data may be used to distinguish between Pnn2 and Pnnm. Nine tests favored the latter choice, four were indeterminate and one was not used. Seven further tests may be made on the basis of physical measurement; of these, three strongly indicated Pnnm, one was indeterminate and three could not be used. The evidence clearly suggests the space group is Pnnm. The use of all reflections, including those with negative magnitude set equal to zero, is essential to avoid ambiguity in the X-ray diffraction tests and achieve the highest reliability. Refinement with weights based on variances of Type A and Type B [Schwarzenbach et al. (1995). Acta Cryst. A51, 565–569] resulted in improved reliability compared with that obtained from a popular empirical weighting scheme. The revised structure differs in several respects from that published previously.


1985 ◽  
Vol 40 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Siegfried Pohl ◽  
Wolfgang Saak ◽  
Bernt Krebs

Abstract The compounds [(C6H5)4As]2 TeCl4 (1), [(C2H5)4 N]2 TeBr4 · CH3CN (2), and [(C2H5)4N]2TeI4 (3) were prepared by the reaction of Te, X2 , and excess (C2H5)4NX (X = Br, I) in acetonitrile solution or by heating of [(C6H5)4 As]2TeCl6 , Te, and (C6H5)4 ASCl for several hours in the same solvent.The structures of 1-3 were determined from single crystal X-ray data.1 crystallizes in the monoclinic space group P21/n with a = 1061.8(2), b = 1614.2(3), c = 1341.7(3) pm, β = 94.21° and Z = 2; 2: tetragonal, P4/mmm, a = 1039.7(2), c = 690.5(1), Z = 1; 3: tetragonal, I4/mmm, a = 1061.7(2), c = 1342.8(4), Z = 2. In 1-3 Te(II) exhibits a square planar coordination. The Te -CI, Te -Br, and Te-I bond lengths were found to be 260.7 (mean), 275.3, and 298.5 pm, respectively.


1992 ◽  
Vol 47 (8) ◽  
pp. 1075-1078 ◽  
Author(s):  
Karin Ruhlandt-Senge ◽  
Ulrich Müller

When hexymethylbenzene-cyclopentadienyl-iron reacts with ozone in dichloromethane, the title compound is one of the products. Its crystal structure was determined by X-ray diffraction (R = 0.145 for 1412 unique reflexions). Crystal data: a = 1815.1(8), b = 1314.8(5), c = 1823.0(8) pm, space group Pbca, Z = 8. The sandwich-like [η6-C6Me6Fe-η5-C5H5]+ ions exhibit large thermal motions, and the CH2C12 molecules are disordered in two orientations. The novel [Fe2Cl6]2- ion has the structure of two tetrahedra sharing an edge. Its IR spectrum is reported.


1998 ◽  
Vol 53 (8) ◽  
pp. 865-870 ◽  
Author(s):  
Marion Graf ◽  
Kurt Merzweiler ◽  
Clemens Bruhn ◽  
Hans-Christian Böttcher

Abstract [Co(But2PH)2I2] (1) reacts with [Ru3(CO)12] in refluxing toluene to give a mixture of products including the novel metal clusters [Ru3(CO)6(μ-H)(μ-I)2(μ-PBut2)(But2PH)] (2) and [Ru3(CO)7(μ-H)(μ-I)(μ-PBut2)2] (3) besides the known complex [Ru3(CO)8(μ-H)2(μ3- PBut)(But2PH)] (4). No cluster expansion products could be observed. Thus the cobalt compound acts merely as a phosphine and iodine transfer reagent. The molecular structures of the metal complexes 1 and 2 were determined by single-crystal X-ray structure analyses. 1 crystallizes in the tetragonal space group P4̄21c with a = 13.230(3), b = 13.230(3), c = 14.788(3)Å, V = 2588.4(9)A . 2 crystallizes in the monoclinic space group P21/c with a = 18.161(2), b = 10.292(2), c = 18.381(2)Å, β = 108.73(10)°, V= 3253.7(8)Å3.


1988 ◽  
Vol 66 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Arthur Mar ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter

The syntheses of the novel anionic tridentate dimethyl(pyrazol-1-yl)(1-oxymethylpyrazolyl)gallate ligand and representative transition metal complexes thereof are reported. The direct reaction of Me3Ga with 1-hydroxymethyl-3,5-dimethylpyrazole leads to the isolation of Me2Ga(μ-OH)(μ-Me2pz)GaMe2•HOCH2Me2pz. Crystals of (μ-hydroxy)(μ-3,5-dimethylpyrazolyl)bis(dimethylgallium) 1-hydroxymethyl-3,5-dimethylpyrazole solvate are monoclinic, a = 33.105(2), b = 7.3048(7), c = 8.8336(6) Å, β = 97.474(7)°, Z = 4, space group P21/n, and those of bis[dimethyl(pyrazol-1-yl)(1-oxymethylpyrazolyl)gallato-N2,N2′,O]nickel(II) are monoclinic, a = 9.6345(3), b = 14.2731(6), c = 18.6356(7) Å, β = 99,660(3)°, Z = 4, space group P21/c. Both structures were solved by conventional heavy atom methods and were refined by full-matrix least-squares procedures to R = 0.044 and 0.037 for 2660 and 3904 reflections with I ≥ 3σ(I), respectively. Mean bond lengths in Me2Ga(μ-OH)(μ-Me2pz)GaMe2•HOCH2Me2pz are Ga—O = 1.918(11), Ga—N = 2.001(5), and Ga—C = 1.955(5) Å. Fac-[Me2Ga(pz)(OCH2pz)]2Ni crystallizes as an all-cis isomer with normal bond lengths and angles at Ga and Ni—O = 1.918(3) and 1.927(3), Ni—N = 2.030(4)–2.111(4) Å. The coordination geometry about Ni is irregular pseudo-octahedral with evidence of both steric and structural trans effects.


1992 ◽  
Vol 47 (11) ◽  
pp. 1501-1504 ◽  
Author(s):  
Erhard Uhlemann, ◽  
Frank Weller

3,5-Diphenyl-1,2-dithiolium hydrogensulphate was prepared by the reaction of bis(thiodibenzoylmethanato)-nickel(II) with thionyl chloride in acetonitrile solution. The compound was characterized by X-ray structure determination (1261 observed, independent reflexions, R = 0,056). Crystal data: a = 543,1(1), b = 1605,7(1), c = 1678,9(2) pm; space group P 212121, Z = 4. By hydrogen bonding the hydrogensulphate ions form chains of weakly helical structure.


1990 ◽  
Vol 45 (2) ◽  
pp. 184-190 ◽  
Author(s):  
A. Heinrich ◽  
H.-L. Keller ◽  
W. Preetz

By cyclic voltammetry investigations in acetonitrile solution it has been shown, that the halogenohydrohexaborates X„B6H6-n2-, X = Cl, Br, I; n = 1-6, undergo a one-electron oxidation to form the corresponding radical anions. The reactions are completely reversible only for the perhalogenated ions B6X62- and for trans-Br4Β6Η22-. The oxidation by Ce(IV) in CH3CN yields deep blue B6I6, orange B6Br6- and yellow green B6Cl6-, characterized by their UV-VIS, IR/Raman spectra and by magnetic measurements. The crystal structures of the paramagnetic, air-stable, blue-black [(n-C4H9)4N]B6I6 (I) and the diamagnetic, colourless [(n-C4H9)4N]2B6I6 (II) were determined from single crystal X-ray diffraction analyses. I is monoclinic, space group P21/c, with a = 14.398(7), b = 14.638(3), c = 16.511(6) Å, β = 109.24(1)° (at —50°C), containing two crystallographically independent centrosymmetric B6 entities, which are strongly distorted with B— B bond lengths between 1.63 and 1.91 and I— I between 2.02 and 2.22 A. II is monoclinic, space group P21, with a = 11.246(3), b = 15.576(4), c = 14.900(4) Å, β = 92.10(1)° (at 23 °C) and contains nearly regular octahedral anions with bond lengths B—B 1.64-1.68 and B—I 2.17-2.21 A.


1978 ◽  
Vol 56 (9) ◽  
pp. 1212-1221 ◽  
Author(s):  
Kenneth S. Chong ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter

Details of the synthesis and physical properties of octahedral transition metal complexes of the tridentate tris chelating ligand [Me2Ga(OCH2CH2NH2)(N2C3H3)]− are given. Crystals of sym-fac-bis[dimethyl(ethanolamino)(1-pyrazolyl)gallato(N(2),O,N]nickel(II) are monoclinic, a = 11.7908(6), b = 7.3158(6), c = 12.5797(8), β = 97.035(7)°, Z = 2, space group P21/n and crystals of the mer isomer are monoclinic, a = 18.6617(7), b = 8.7941(4), c = 13.5670(8), β = 91,766(4)°, Z = 4, space group P21/c. The structures were solved by Patterson and Fourier syntheses and were refined by full-matrix least-squares procedures to final R values of 0.048 and 0.052 for 1881 and 2573 reflections with I ≥ 3σ(I) for the fac and mer isomers respectively. The nickel atoms in both structures were found to have distorted octahedral coordination geometry. Bond lengths (corrected for libration) are: Ni—O, 2.090(3); Ni—N, 2.085(3) and 2.112(3); Ga—O, 1.908(3); Ga—N, 2.010(3); and Ga—C, 1.979(5) and 1.981(6) Å for the fac isomer, and Ni—O, 2.045(4) and 2.049(4); Ni—N, 2.091 (4)-2.156(5); Ga—O, 1.898(4) and 1.899(4); Ga—N, two at 1.991 (5); and Ga—C, 1.948(8)-1.971 (7) Å for the mer isomer.


2003 ◽  
Vol 18 (2) ◽  
pp. 144-146
Author(s):  
V. G. Vlasenko ◽  
A. T. Shuvaev ◽  
V. A. Shuvaeva ◽  
A. I. Uraev

Two novel copper and iron chelates have been studied by powder diffraction. The cell parameters for triclinic (space group P 1 (2)) C25H21CuN3SO4 are a=9.636(2) Å; b=11.014(1) Å; c=11.233(3) Å; α=83.55(2); β=82.45(6); γ=76.36(2); Z=2; Dx=1.456 g cm−3. The monoclinic cell parameters (space group P 21/c (14)) for C40H30Cl4Fe2N8S2 are a=11.464(8) Å; b=17.462(1) Å; c=20.550(6) Å; β=103.534(1); Z=2; Dx=1.356 g cm−3.


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