Silaheterocyclen: Molekülstruktur eines 3-Oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptans / Silaheterocycles: Molecular Structure of a 3-Oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptane

1989 ◽  
Vol 44 (7) ◽  
pp. 796-799 ◽  
Author(s):  
Gabriele Reber ◽  
Jürgen Riede ◽  
Nils Wiberg ◽  
Gerhard Wagner ◽  
Gerhard Müller

According to an X-ray structure analysis 1,5-bis(di-tert-butylmethylsilyl)-2,2,4,4,6,6,7,7-octamethyl-3-oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptane (1) is a rigid bicyclic molecule consisting of a 1,3-disilacyclobutane ring whose 2,4 positions are bridged by a Me2Si—O—SiMe2 fragment. The four-membered ring is non-planar with a dihedral angle of 33.8° along the C—C axis. The intraring valence angles at carbon are significantly smaller than those at silicon leading to a transannular Si ··· Si distance of only 2.558(1) Å (triclinic, space group P 1̄ with a = 9.125(2), b = 12.668(2), c = 15.499(3) Å, α = 101.25(1), β = 87.87(1), γ = 96.88(1)°, V = 1744.4 Å3 R (wR) = 0.044 (0.051) for 316 refined parameters and 5156 observables).

1995 ◽  
Vol 50 (12) ◽  
pp. 1811-1817 ◽  
Author(s):  
Max Herberhold ◽  
Christian Köhler ◽  
Wolfgang Milius ◽  
Bernd Wrackmeyer

N,N′-Dialkyl sulfur diimides (1), R(NSN)R [R = Me (a), Et (b), nPr (c), nBu (d)] react with cyclic bis(amino)stannylenes such as 1,3-di-tert-butyl-4,4-dimethyl-1,3,4,2λ2-diazasilastannetedine (2) or 1,3-di-tert-butyl-4,4,5,5-tetramethyl-1,3,4,5,2λ2-diazadisilastannolidine (3) in a 2:1 ratio to give the new spiro-tin(IV) compounds 5a-d, 6b and 6c, built from the respective cyclic bis(amino)stannylene and a seven-membered ring in which the two sulfur diimide groups are coupled via a N-N bond and across the tin atom. A 1:1 adduct 4 is proposed as an intermediate which is the final product 4e in the case of R = tBu (1e). The products were characterized by multinuclear magnetic resonance (1H, 13C, 15N, 29Si, 119Sn NMR), and in the case of 5c the molecular structure was determined by single crystal X-ray structure analysis [monoclinic, space group C2/c ; a = 1504.1(3), b = 1393.3(3), c = 1688.6(3) pm; β = 115.71(3)°].


1983 ◽  
Vol 38 (3) ◽  
pp. 347-349 ◽  
Author(s):  
Herbert W. Roesky ◽  
Pierre Schäfer ◽  
Mathias Noltemeyer ◽  
George M. Sheldrick

Abstract The six membered ring of composition (CH3)2NCN3S2Cl2 3 a was prepared from N,N-dimethylguanidinhydrochloride and trithiadiazindichloride. 3 a was characterized on the basis of mass, 1H, 13C NMR spectra and X-ray structure analysis. Crystals of 3 a are monoclinic, space group P21/c, with a = 660.3(6), b = 834.5(7), c = 1774.7(15) pm, β = 112.83(6)° and Z = 4. The C2N unit lies approximately in the plane of the [-CNSNSN-] ring, with both Cl atoms on the same side of the ring.


1992 ◽  
Vol 47 (2) ◽  
pp. 171-174 ◽  
Author(s):  
H. W. Roesky ◽  
T. Raubold ◽  
M. Noltemeyer ◽  
M. Witt ◽  
R. Bohra

1The reaction of ClSO2N = PPh2Cl () with NH3 yields H2NSO2N = PPh2NH2 (2).This compound is converted to Me3Si(H)NSO2N = PPh2N(H)SiMe3 (3) by Me3SiNMe2. 3 reacts with WOCl4 under elimination of (Me3Si)2O and ClSO2NH2 to yield the eight-membered ring system (Cl3WNPPh2N)2 (4).The molecular structure of 4 was investigated by an X-ray structure analysis.


1997 ◽  
Vol 52 (7) ◽  
pp. 810-814 ◽  
Author(s):  
Hans-Christian Böttcher ◽  
Kurt Merzweiler ◽  
Clemens Bruhn

Abstract The reaction of the phosphido-bridged metal carbonyl [FeRh(CO)6(μ-PBut2)] (1) with dppm [dppm = bis(diphenylphosphino)methane] leads to the heterobimetallic complex [FeRh(μ-CO)(CO)3(μ-PBut2)(μ-dppm)] (2) in good yields. The molecular structure of 2 was determined at room temperature [triclinic, space group P1̄, a = 9.509(6), b = 13.637(5), c = 14.926(8) Å, α = 81.38(4), β = 82.75(4), γ = 71.25(4)°]. The compound acts as a homogeneous catalyst precursor in the hydroformylation reaction of ethylene, but it decomposes during this process.


1975 ◽  
Vol 30 (1-2) ◽  
pp. 14-18 ◽  
Author(s):  
R. Mergehenn ◽  
L. Merz ◽  
W. Haase

The crystal and molecular structure of β-bromo(diethylaminoethanolato)copper(II) has been determined from three dimensional X-ray diffractometer data. The compound crystallizes in the triclinic space group Pï with one dimer in a unit cell of dimensions α=10.180(II), b=7.999(9), c=6.227(7) Å and a=110.69(4), β=103.12(4), γ=73.82(4)[°]. The structure was refined by least-squares methods using 1944 independent reflexions to give a final R-index of 0,05. The molecule consists of dimeric Cu2O2-units with Cu—O distances of 1.900(4) Å and 1.914(4) A, respectively. The dimers are additional bridged by bromines, so that a “polymeric” structure results; Cu—Br distances are 2.357(2) and 3.660(2) A, respectively. The Cu—Cu distances are 3.003(2) (oxygen bridges) and 4.506(2) Å (bromine bridges).


1997 ◽  
Vol 52 (6) ◽  
pp. 693-695 ◽  
Author(s):  
Heike Hefele ◽  
Erhard Uhlemann ◽  
Frank Weller

A new binuclear vanadium( V) complex was synthesized by reaction of an aqueous oxovanadium(IV) sulfate solution with 2-(2′-hydroxyphenyl)-8-quinolinol dissolved in methanol. The molecular structure of the complex was determined by X-ray structure analysis. Crystal data: a = 10.004(3), b = 9.325(2), c = 15.089(3) Å; β = 91.95(2)°; space group P21/n, Z = 4.


1988 ◽  
Vol 43 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Bernhard Glaser ◽  
Erwin P. Mayer ◽  
Heinrich Nöth ◽  
Wilfried Rattay ◽  
Ulrich Wietelmann

Abstract [2+2]-Cycloadditions of 9-Fluorenylidentetramethylpiperidinoboranes have been studied with selected olefines, acetylenes and iminoboranes. No reactions with olefines were observed. While propiolic methylester reacts exclusively at the carbonyl bond producing the oxaboretane 5, alkines such as diethylamino-alkines, cyclo-octine and phenylacetylene provide access to the'1,2-dihydroboretenes 6, 3 and 2. Tetramethylpiperidinoiminoboranes make 1.2.4-azadiboretidines 7 available.6a and 7a contain a folded four-membered ring as shown by X-ray structure analysis. There is only a weak 1,3-intraannular interaction due to BN-;r-bonding of the boron atoms with their exocyclic amino group.


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.


1977 ◽  
Vol 55 (10) ◽  
pp. 1619-1623 ◽  
Author(s):  
George I. Birnbaum

In order to determine the orientation of the isopropenyl group and confirm the stereochemistry at other chiral centers in lubimin (1) and hydroxylubimin (2), two antifungal sesquiterpenes, an X-ray structure analysis of 2 was carried out. Crystals of 2 are orthorhombic, space group P212121, a = 6.190, b = 7.210, c = 63.082 Å, Z = 8. The structure was solved by direct methods and refined to R = 0.045. In both independent molecules the six-membered ring is chair-shaped with all four substituents equatorially oriented. The five-membered ring, attached by a spiro junction, is a half-chair with the isopropenyl substituent in an equatorial position. This side-chain is trans to the methyl-bearing carbon in the six-membered ring.


2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Rina Mondal ◽  
Nayim Sepay ◽  
Debajyoti Ghoshal ◽  
Asok K. Mallik

Single crystal X-ray diffraction of two macrocyclic bischalcones, namely, (2E,25E)-11,17,33,37-tetraoxapentacyclo[36.4.0.05,10.018,23.027,32]dotetraconta-1(42),2,5,7,9,18,20,22,25,27,29,31,38,40-tetradecaene-4,24-dione(1) and (2E,24E)-11,16,32,37-tetraoxapentacyclo[36.4.0.05,10.017,22.026,31]dotetraconta-1(42),2,5,7,9,17,19,21,24,26,28,30,38,40-tetradecaene-4,23-dione(2), each containing a 26-membered ring, has been studied. Compound 1 belongs to the monoclinic system, space group C2/c with a = 34.3615(9) Å, b = 12.7995(3) Å, c = 14.6231(3) Å, β = 96.912(2)°,  V = 6,384.6(3) Å3, and Z = 8. Compound 2 is triclinic, space group P-1 with a = 10.066(2) Å, b = 10.670(3) Å, c = 16.590(3) Å, α = 85.95(2), β = 89.244(14), γ = 62.211(13), V = 1572.0(6) Å3, and Z = 2. Intermolecular C–H⋯O hydrogen bonding interactions are present in both compounds.


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