Cyclische diazastannylene: XXII. Zur umsetzung eines bis(amino)stannylens mit organylphosphanen, -methylen-phosphoranen, -phosphaniminen, -oxiden und -sulfiden

1,3-Di-t-butyl-2,2-dimethyl-1,3,2,4λ²-diazasilastannetidin (I) was allowed to react with the phosphanes PEt₃ and PPh₃ as well as with Me₃PCH₂, Ph₃PCH₂, Ph₃PNH, Me₃PO and Et₃PS. While the phosphor ylides and the phosphane oxide interact with I to yield crystalline acid-base adducts, no stable adducts can be isolated with the phosphanes and the phosphane sulfide. The adduct of Ph₃PCH₂ and I crystallizes with one benzene molecule per formula unit in the monoclinic space group P2₁/c (a 1188.2(8), b 1438.4(2), c 2169.4(5) pm, β 106.5(4)°). I and Ph₃PCH₂ are linked together by a SnC bond of 240.3(10) pm. The electron transfer from the ylide-carbon to the tin atom can be evaluated from the PC bond length of 174.3(11) pm. The phosphaneimine reacts with I by displacement of the tin atom in I by hydrogen atoms yielding N, N ′-di-t-butyl-Si, Si-dimethylsilazanean and Sn(NPPh₃)₄, and oxidation at the tin atom. 3 molecules of benzene are crystallizing together with one formula unit of Sn(NPPh₃)₄ (monoclinic; C2/c; a 2470.0(4), b 1643.6(6), c 2382.7(4) pm, β 128.1(3)°). The tin atom is the centre of a tetrahedron of nitrogen atoms, the mean SnN-bond length (197.5 pm) being the shortest so far reported.     

The crystal and molecular structure of BIS(1,3-diphenylpropane-1,3-dionato)-Di-n-butyltin(IV)

The crystal and molecular structure of bis(1,3-diphenylpropane-1,3-dianoto)di-n-butyltin(IV) has been determined from three-dimensional X-ray data by the heavy-atom method. The space group is P2₁/n. Unit cell constants are a 1117.56(30), b 857.87(16), c 1758.36(51) pm, and β 99.398(20)°. The observed density of the yellow crystals (m.p. 92–94°C) is 1.38 g ml⁻³ and requires two molecules per unit cell. The molecule has a center of symmetry. Refinement converged to give final discrepancy indices, R = 0.0481, R_w = 0.0607; and goodness-of-fit (GOF) was 3.216 for 1688 observed reflections. The molecular skeleton about tin is a slightly distorted octahedron with bond distances: SnC, 212 pm; and SnO, 219 and 220 pm. The O(1)SnO(2) bond angle is 83.8°, and CSnO bond angles are very nearly 90°. The structural parameters are compared with those of other organotin complexes of similar stoichometry.     

Skew-trapezoidal bipyramidal diorganotin(IV) bischelates. Crystal structure of dimethylbis(2-pyridinethiolato-N-oxide)tin(IV)

Dimethylbis(2-pyridinethiolato-N-oxide)tin(IV), Me₂Sn(2-SPyO)₂, crystallizes in space group P2₁/c with a 9.877(3), b 11.980(4), c 13.577(3) Å, β 109.1(2)° and Z = 4. The structure was refined to R_F = 0.036 for 2263 Mo-K_α observed reflections. The coordination geometry at tin is a skew-trapezoidal bipyramid, with the oxygen [SnO 2.356(3), 2.410(4) Å] and sulfur [SnS 2.536(1), 2.566(1) Å] atoms of the chelating groups occupying the trapezoidal plane and the methyl groups [SnC 2.106(6), 2.128(7) Å] occupying the apical positions. The methyl-tin-methyl skeleton is bent [CSnC 138.9(2)°]. The SSnS angle is 77.8(1)°, but the OSnO angle is opened to 136.7(1)° to accommodate the intruding methyl groups. The carbontincarbon angles predicted from quadrupole splitting (^119mSn Mössbauer) and one-bond ¹¹⁹Sn¹³C coupling constant (solution ¹³C NMR) data agree closely with the experimental value.     

195Pt, 119Sn and 31P NMR studies of alkyl,aryl and acyl trichlorostannate complexes of platinum(II). The crystal structure of trans-[Pt(SnCl3)(COC6H5)(PEt3)2]

¹⁹⁵Pt, ¹¹⁹Sn and ³¹P NMR characteristics of the complexes trans-[Pt(SnCl₃)(carbon ligand)(PEt₃)₂] (1a-1e) are reported, (carbon ligand = CH₃ (1a), CH₂Ph (1b), COPh (1c), C₆Cl₅ (1d), C₆Cl₄Y (e); Y = meta- and para-NO₂, CF₃, Br, H, CH₃, OCH₃, or Pt(SnCl₃)(PEt₃)₂. The values of ¹J(¹⁹⁵Pt, ¹¹⁹Sn) vary from 2376 to 11895 Hz with the COPh ligand having the smallest and the C₆Cl₅ ligand the largest value, making a total range for this coupling constant, when the dimer syn-trans-[PtCl(SnCl₃)(PEt₃)]₂ is included, of ca. 33000 Hz. In the meta- and para-substituted phenyl complexes ¹J(¹⁹⁵Pt, ¹¹⁹Sn) (a) is greater for electron-withdrawing substituents, (b) varies more for the meta-substituted derivatives (5634 to 7906 Hz) than for the para analogues (6088 to 7644 Hz) and (c) has the lowest values when the Pt(SnCl₃)(PEt₃)₂ group is the meta- or para-substituent. The direction of the change in ¹J(¹⁹⁵Pt, ¹¹⁹Sn) is opposite to that found for ¹J(¹⁹⁵Pt, ¹¹⁹P). For the aryl complexes linear correlations are observed between δ(¹¹⁹Sn), ¹J(¹⁹⁵Pt, ¹¹⁹Sn), ¹J(¹⁹⁵Pt, ³¹P), ¹J(¹¹⁹Sn, ³¹P) and the Hammett substituent constant σⁿ. δ(¹¹⁹Sn) and ¹J(¹⁹⁵Pt, ¹¹⁹Sn) are related linearly to v(Pt-H) in the complexes trans-[PtH(C₆H₄Y)(PEt₃)₂]; δ(¹¹⁹Sn) and δ(¹H) (hydride) are also linearly related. Based on ¹J(¹⁹⁵Pt, ¹¹⁹Sn), the acyl ligand is suggested to have a very large NMR trans influence. The differences in the NMR parameters for (1a-e) are rationalized in terms of differing σ- and π-bonding abilities of the carbon ligands.The structure of 1c has been determined by crystallographic methods. The complex has a slightly distorted square planar geometry with trans-PEt₃ ligands. Relevant bond lengths (Å) and bond angles (°) are: PtSn, 2.634(1), PtP, 2.324(4) and 2.329(4), PtC, 2.05(1); PPtP, 170.7(6), SnPtC, 173.0(3), SnPtP, 92.1(1), 91.7(1), PPtC, 88.8(4) and 88.3(4). The PtSn bond separation is the longest yet observed for square-planar platinum trichlorostannate complexes, and would be consistent with a large crystallographic trans influence of the benzoyl ligand. The PtSn bond separation is shown to correlate with ¹J(¹⁹⁵Pt, ¹¹⁹Sn).     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden : VII. Trimethylphosphoranylidenmethyl(trimethylsiloxy)carben-komplexe von chrom,molybdän und wolfram: aufbau einer metallvinyl-einheit durch c(carbanion)c(carben)-π-wechselwirkung und photochemische e/z-isomerisierung

The treatment of the hexacarbonylmetal compounds M(CO)₆ (M = Cr. Mo, W) with two equivalents Me₃PCH₂ yields the phosphonium acylmetalphosphorus ylides Me₄P[(CO)₅MC(O)CHPMe₃] 1a–1c. Their reaction with Me₃SiOSO₂CF₃ leads via O-silylation to formation of the neutral “siloxy(ylidecarbene) complexes” (CO)₅MC(OSiMe₃)CHPMe₃2a–2c, which are protonated by HX (X = Cl, CF₃SO₃) to give the thermolabile carbene complexes [(CO)₅MC(OSiMe₃)H₂CPMe₃]X, 3a, 3b. ¹H, ¹³C NMR and IR data suggest, that delocalization of the ylidic charge to the carbene carbon generates a metal-coordinated vinyl group in the case of 2a–2c. In addition this fact is proved by the X-ray analysis of 2c, for which a C(ylide)C(carbene) bond distance of 133 pm is found. 2a–2c are obtained as pure E-isomers but can be converted to the Z-isomers 2a′–2c′ upon photolysis.     

Fluorenylsilane : III. Über die umsetzung von 9-fluorenyl-tris(trimethylsilyl)silan mit chlor

9-Fluorenyltris(trimethylsilyl)silane (A) reacts with chlorine in CCl₄ to give dichloro-9-fluorenyltrimethylsilylsilane (B) in good yield. B is characterized spectroscopically and by X-ray structure analysis; it crystallizes in the triclinic space group P$\text{1}$ with a 950(2), b 1367(3), c 1138(2) pm, α 137.5(1), β 109.9(2), γ 89.8(2)°. The conformation of B is staggered with approximate C_s-symmetry; C(9)Si 187.6(5), SiSi 233.2(4), SiCl 207.1(3) and 205.3(3) pm.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XXXIII. Die Struktur des Bis(triphenylsilyl)sulfids

Contributions to the Chemistry of Silicon Sulphur Compounds. XXXIII. Structure of Bis (triphenylsilyl)sulphide The condensation of triphenylsilanethiol yielded bis(triphenylsilyl)sulphide ( 1 ). The compound is remarkable resistent to hydrolysis. 1 crystallizes monoclinically [P2₁/n (No. 14): a = 1707.8 pm; b = 1454.6 pm; c = 1225.0 pm; β = 97.27°; Z = 4; 4470 h k l; R = 0.053]. The molecule is bent with a bond angle Si? S? Si = 112.0°. The mean bond distances Si? S and Si? C are 215.2 pm and 187.4 pm, respectively. Some structural details are discussed.     

Untersuchungen an Polyhalogeniden. XXIII. Kristallstrukturen der N-Alkylurotropiniumtriiodide UrRI3 mit R = Methyl,Ethyl, n-Propyl und n-Butyl

Studies on Polyhalides. 23. Crystal Structures of N-Alkylurotropinium Triiodides UrRI₃ with R = Methyl, Ethyl, n-Propyl, and n-Butyl The salts UrRI₃ may be prepared by the reaction of N-alkylurotropinium iodides UrRI with iodine I₂ at room temperature from aqueous solution. N-methylurotropinium triiodide C₇H₁₅N₄I₃ crystallizes monoclinically in P2₁/c with a = 1300.8(2) pm, b = 1276.0(3) pm, c = 859.3(2) pm, β = 94.75(2)° and Z = 4. The crystal structure is built up from layers of cations UrMe⁺ and of linear symmetric triiodide ions I₃^? alternating along [100]. N-ethylurotropinium triiodide C₈H₁₇N₄I₃ crystallizes orthorhombically in Pnma with a = 1397.3(5) pm, b = 1221.3(2) pm, c = 886.2(2) pm and Z = 4. The cationic (UrEt⁺) and anionic (I₃^?) layers alternate along [0 10]. N-propylurotropinium triiodide C₉H₁₉N₄I₃ crystallizes monoclinically in P2₁/c with a = 1885.7(5) pm, b = 1657.1(5) pm, c = 1700.5(4) pm, β = 112.39(2)° and Z = 12. The three independent cations and anions are slightly, but differently distorted. N-butylurotropinium triiodide C₁₀H₂₁N₄I₃ crystallizes monoclinically in P2₁/m with a = 991.8(3) pm, b = 757.8(2) pm, c = 1128.2(2) pm, β = 90.73(2)° and Z = 2. The crystal structure is stacked by alternating cationic and anionic layers along [001]. The triiodide ion is asymmetric and linear.     

Darstellung, eigenschaften und kristallstruktur von methylgalliumdiacetat CH3Ga(OOCCH3)2

Trimethylgallium reacts with acetic acid in a $\text{1}\text{2}$ molar ratio yielding methylgallium diacetate, CH₃Ga(OOCCH₃)_2? The structure is determined by vibrational spectroscopy and the crystal structure is described. Methylgallium diacetate crystallizes in the monoclinic space group P2₁/c with lattice constants a 776.5, b 1428.9, c 1406.3 pm, β 91.87° and eight formula units per cell. The monomers are linked together by acetate groups forming polymeric, waved layers. Besides the bridging acetate there are also “free” acetate groups coordinated at the distorted trigonal-bipyramidal coordinated Ga(1) atom. A second gallium atom Ga(2) is coordinated distorted tetrahedrally, the acetate groups bonded to Ga(2) being all bridging. The mean intermolecular distances are: GaC 194.6 pm, Ga(1)O_apical 215.3 pm, Ga(1)O_eq(bridge) 194.3 pm, Ga(1)O_eq(free) 187.3 pm, Ga(2)O 191.3 pm, CC 151.5 pm, CO 119.4 pm, CO 131.1 pm, CO 127.3 pm.     

Über gemischte bindungen in der IV. hauptgruppe: III. Octaphenylpropan-analoga Ph3SnSiPh2SnPh3 und Ph3SnGePh2SnPh3, korrelation zwischen geminalen NMR-kopplungen 2J(SnMSn) und nicht-bindenden Sn⋯Sn-abständen

Reaction of Ph₃SnLi with Ph₂SiCl₂ or Ph₂GeCl₂ at −78°C in THF yields (Ph₃Sn)₂SiPh₂ (1) and (Ph₃Sn)₂GePh₂ (2). The crystal structure of 1 (R = 0.075) exhibits SnSi distances of 257.2(4) and 257.9(5) pm, an SnSiSn angle of 118.5(2)°, and a central C₃SnSiC₂SnC₃ molecular skeleton with symmetry close to C₂. The geminal NMR coupling ²J(¹¹⁹Sn ⋯ ¹¹⁹Sn) in 1, and in a tri-, tetra- and pentastannane series shows a linear correlation to their respective non-bonded d(Sn ⋯ Sn) distances (I(t-Bu₂Sn)₄I: 20 Hz/496 pm; 1: 724 Hz/443 pm).     

Über polystannane: II. I(t-Bu2Sn)4I,ein 1,4-difunktionelles tetrastannan

The compound I(t-Bu₂Sn)₄I has been synthesized by controlled cleavage of the related cyclotetrastannane (t-Bu₂Sn)₄ with iodine in toluene. Both compounds have been investigated by mass, NMR and vibrational spectra. I(t-Bu₂Sn)₄I: δ(¹¹⁹Sn_terminal) 67.7, δ(Sn_central) 17.4 ppm; ¹J(SnSn) 2199 (terminal-central) and 1575 (central-central), ²J(SnSn) 20 (terminal-central), ³J (SnSn) 307 Hz (terminal-terminal); ν(SnSn) 119, ν(SnI) 167 cm^?1. (t-Bu₂Sn)₄: δ(Sn) 87.4 ppm; ν(SnSn) 125 cm^?1. The crystal structure of I(t-Bu₂Sn)₄I has been determined (R = 0.071): bond lengths SnSn 289.5(1) (terminal-central) and 292.4(1) (central-central), SnI 275.3(1) pm. The conformation of the chain ISn₄I is all trans.     

The crystal structure of barium manganese(II) iron(III) fluoride BaMnFeF7

The crystal structure of the monoclinic compound BaMnFeF₇ has been determined: a = 553.2(1), b = 1098.0(2), c = 918.3(1) pm, β = 94.67(1)°, V = 555.9(3) × 10^?24 cm³, Z = 4. All atoms are in general positions of space group $\text{P2}{}_1\text{c}$, weighted R = 0.031, using 1771 independent single-crystal reflections with I > 2σ(I). The structure consists of edge-sharing dinuclear Mn₂F^6?₁₀ units (MnMn = 322.2 pm), linked via corners by intermediate FeF₆ octahedra, at which two cis ligands remain unbridged. The average distances in the distorted octahedra are MnF = 211.6 pm and FeF = 192.7 pm. The barium atoms are irregularly 12-coordinated with a mean distance BaF = 290.5 pm. The structure is discussed in relation to the trigonal weberite Na₂MnFeF₇ and others.     

Übergangsmetall-thioketon-komplexe. Synthese und strukturaufklärung von tetracarbonyl(diphenylcyclopropenthion)eisen, [C3(C6H5)2S]Fe(CO)4

Diphenylcyclopropenethione reacts with Fe₂(CO)₉ in THF to give tetracarbonyl(diphenylcyclopropenethione)iron (C₃Ph₂S)Fe(CO)₄. The crystal structure was determined by single crystal X-ray analysis. The compound crystallizes in the triclinic space group P$\text{1}$ with lattice constants a 1520.3(5), b 1026.1(3), c 933.5(2) pm; α 120.58(2), β 109.36(2), γ 111.72(2)°; Z 2. The molecule consists of an unchanged diphenylcyclopropenethione ligand coordinated via the sulphur atom to an Fe(CO)₄ group in the axial position. The CS distance is 165.2(7) pm with an FeSC angle of 111.2(2)°.     

Über die Decamethylferroceniumpolyiodide [(Me5C5)2Fe]Ix mit x = 3, 5 und 6,5. Darstellung und strukturelle Charakterisierung eines Triiodids (DMFc)I3, eines Pentaiodids (DMFc)I5 und eines Hexacosaiodids (DMFc)4I26

Studies on Polyhalides. 30 On Decamethylferriciniumpolyiodides [(Me₅C₅)₂Fe]I_x with x = 3, 5, 6.5: Preparation and Crystal Structures of a Triiodide (DMFc)I₃, a Pentaiodide (DMFc)I₅ and a Hexacosaiodide (DMFc)₄I₂₆ Decamethylferrocene (DMFc) may be oxidized by iodine analogous to ferrocene (Fc) to the decamethylferrocenium ion (DMFc)⁺ and precipitated as the crystalline solids decamethylferrocenium triiodide (DMFc)I₃, decamethylferrocenium pentaiodide (DMFc)I₅ and tetracisdecamethylferrocenium hexacosaiodide (DMFc)₄I₂₆. The two compounds with higher iodine content are new. These are characterized by X-ray diffraction methods on single crystals. The structures are built up from complex cations of expected geometry and isolated or remarkably connected polyiodide ions. Decamethylferrocenium triiodide C₂₀H₃₀FeI₃ crystallizes monoclinically in C2/m with a = 1489.9(4) pm, b = 1133.0(2) pm, c = 765.9(3) pm, β = 111.76(3)° and Z = 2. The crystal structure follows the CsCl-type and contains isolated triiodide ions of the linear symmetric form. Decamethylferrocenium pentaiodide C₂₀H₃₀FeI₅ crystallizes monoclinically in P2₁/c with a = 1130.0(2) pm, b = 1442.6(1) pm, c = 1716.6(2) pm, β = 96.62(1)° and Z = 4. The crystal structure may be deduced from the primitiv quadratic bundle of alternating cationic and anionic rods. It contains exceptionally isolated somewhat opened out pentaiodide ions. Tetrakisdecamethylferrocenium hexacosaiodide (C₂₀H₃₀Fe)₄I₂₆ crystallises monoclinically in P2₁/n with a = 1331.3(8) pm, b = 1319.4(4) pm, c = 3564(2) pm, β = 90.84(5)° and Z = 2. The crystal structure of this compound with unusual composition may be described as an inclusion compound with channels for the cations. The outstanding anionic grating may be derived from the primitive cubic lattice of iodide ions with iodine bridges on all edges by removing systematically 1/12 of the iodine molecules.     

The crystal structure of triphenyltin isothiocyanate

The crystal structure of Ph₃SnNCS has been determined by single crystal X-ray diffraction. The crystals are monoclinic, P2₁, a = 19.02(3), b = 11.67(2), c = 15.49(2)Å;, β = 95.64(10)°, Z = 8. The molecules are arranged in infinite zig-zag S…SnNCS…Sn&.sbnd; chains similar to those in Me₃SnNCS, but with slightly longer SnN, shorter SnS bonds, and almost planar SnC₃ units. Principal mean bond lengths and angles are: SnN, 2.22(5); NC, 1.17(8); CS, 1.58(7); SSn, 2.92(1); SnC, 2.09(3); CC, 1.38(2)Å; SnNCm 161(4); CSSn, 97(3); SSnN, 175(3) and CSnC, 119.8(1.5)°.     

Bildung siliciumorganischer Verbindungen. 94. Die Kristallstruktur des Hexaphenyltrisilacyclohexans Si3C39H36

Formation of Organosilicon Compounds. 94. Crystal Structure of Hexaphenyltrisilacyclohexane Si₃C₃₉H₃₆ 1.1.3.3.5.5-Hexaphenyl-1.3.5-trisilacyclohexane crystallizes monoclinically in the space group P2₁/n (No. 14) with a = 1718.3 pm, b = 1769.2 pm, c = 1091.4 pm, β = 90.72° and Z = 4 molecules per unit cell. The trisilacyclohexane sceleton is present in a flattened twist boat conformation with mean bond angles of 110.0° at the Si atoms and 117.9° at the C atoms, respectively. The mean bond lengths are d(Si? C) = 187.1 pm in the six membered ring and 187.9 pm to the substituents.     

Strukturchemie dreigliedriger brückenliganden : II. Molekülstruktur eines zweikernigen titan-komplexes mit phosphonium-bismethylid-brücken

Ti₂(OMe)₆[(CH₂)₂PMe₂]₂ crystallizes in the triclinic space group P$\text{1}$ with a 860(1), b 968(1), c 1448(3) pm, α 103.22(14), β 92.02(13) and γ 93.77(14)° Two halves, each of an independent molecule are within the asymmetric unit. The titanium atoms (TiTi 325.4 and 326.5 pm) are bridged by two methoxy groups and two dimethylphosphonium-bismethylide ligands, the latter being trans to each other. By two additional methoxy groups each titanium atom reaches approximate octahedral coordination. TiO (bridge) 205 pm, TiO (termial) 180 pm, TiC 225 pm (mean values). Adaptation of the bite width of the ylide ligands to the metal—metal distance essentially results from C_s configuration of the five membered Ti₂C₂P rings and from opening of the TiCP angles to 119.5°. General aspects of the geometry of phosphonium-bismethylide ligands are discussed.     

Beiträge zur Strukturchemie phosphorhaltiger Ketten und Ringe. 7. Die Kristall- und Molekülstruktur des Diphosphagermetans (t-BuP)2(GePh2)2

Structural Chemistry of Phosphorus Containing Chains and Rings. 7. Molecular and Crystal Structure of the Diphosphagermetane (t-BuP)₂(GePh₂)₂ The compound 1,2-di-tert-butyl-3,3,4,4-tetraphenyl-diphospha-3,4-digerma-cyclobutan, (t-BuP)₂(GePh₂)₂, crystallizes monoclinically in the space group P2₁/c with a = 996.8 pm, b = 1337.3 pm, c = 2403.4 pm, β = 92.66° and Z = 4 formula units. The main structural feature is a non-planar four-membered ring. The (average) bond lengths are d(Ge? Ge) = 242.1 pm, d(Ge? P) = 234.0 pm, d(P? P) = 221.6 pm, d(Ge? C) = 194.9 pm, d(P? C) = 188.tyl4 pm, d(C? C)_Ph = 136.l5 pm, d(C? C)_t-Bu = 151.8 pm, d(C? H)_Ph = 91 pm, d(C? H)_t-Bu ? 95 pm. The geometry of the substituents phenyl and tert-butyl is quite normal.     

The formation and molecular structure of di-η5-cyclopentadienyl{2-1(dimethylamino)methyl]phenyl-C,N}yttrium

A reaction between 2-lithio-N,N-dimethylbenzylamine (1) and di-μ-chlorotetra-η⁵-cyclopentadienyldiyttrium (2) in ethyl ether solution has produced di-η⁵-cyclopentadienyl{2-[(dimethylamino)methyl]phenyl-C, N}yttrium (η⁵-C₅H₅)₂Y(C₆H₄-CH₂NMe₂) (3), in 71% yield. The product, which represents the second known aryl derivative of yttrium, has been characterized by elemental analysis and ¹H NMR data as well as by a single-crystal X-ray diffraction study.(η⁵-C₅H₅)₂Y(C₆H₄-2-CH₂NMe₂) crystallizes in the monoclinic space group P2₁/c with lattice parameters a 8.310(3), b 26.972(8), c 15.548(6) Å, β 95.88(3)°, and D_calc 1.35 g cm^?3 for Z = 4. Least-squares refinement gave a final R value of 0.102 using 1739 independent observed reflections. There are two molecules in the asymmetric unit. Each yttrium atom is η⁵-coordinated to two cyclopentadienyl ligands and sigma bonded to the ortho-carbon and -nitrogen atoms of the dimethylbenzylamine ligand. The YC(σ) bond distances are identical at 2.41(2) Å; the two YN bond lengths are 2.43(2) and 2.54(2) Å.     

Bildung siliciumorganischer Verbindungen. 112. Über den Einfluß der Reaktionsbedingungen auf die Umsetzung von (Cl3Si)2CCl2 mit Silicium. Die Struktur von 2,2,3,3,5,5,6,6-Octachlor-1,4-bis(trichlorsilyl)-2,3,5,6-tetrasilabicyclo[2.1.1]hexan und 1,1,3,4,6,6-Hexakis(trichlorsilyl)hexatetraen

Formation of Organosilicon Compounds. 112. The Influence of Reaction Conditions on the Reaction of (Cl₃Si)₂CCl₂ with Silicon. The Structures of 2,2,3,3,5,5,6,6-Octachloro-1,4-bis(trichlorosilyl)-2,3,5,6-tetrasilabicyclo[2.1.1]-hexane and 1,1,3,4,6,6-Hexakis(trichlorosilyl)hexatetraene While reactions of (Cl₃Si)₂CCl₂ 1 with Si(Cu) in a fluid bed at 320°C exclusively yield products by silylation of the CCl₂ group in 1 does the reaction in a stirred bed preferrably give rize to chlorosilanes containing C? C double and triple bonds. Compounds 5, 6, 7, 8 and 9 in Tab. 1 belong to the first group, whereas 3 and 4 belong to the second one. The reaction of 1 with elemental copper under dehalogenation at carbon produces 3, 4 and 11 . In the reaction of 1 with CaSi₂ no additional Si? C bonds are formed, exclusively chlorosilanes with multiple C? C bonds as 3, 4 and 10 were found besides of SiCl₄. The bicyclo[2.1.1]hexane 6 (Tab. 1) crystallizes monoclinically in the space group C2/c (no. 15) with a = 1557.8, b = 857.4, c = 1727.3 pm, β = 104.34° und Z = 4 molecules per unit cell; the hexatetraene 10 (Tab. 1) crystallizes monoclinically in the space group C2/m (no. 12) with a = 1189.6, b = 1433.8, c = 983.5 pm, β = 98.75° pm, and Z = 2 molecules per unit cell. The skeleton of 6 is a system of high bond stress with 2-C₂ symmetry. The strongly folded (138.8°) four-membered ring (sum of angles = 344.2°) and the presence of both a Si? Si bond length of 238.2 pm and a Si? Si non-bonding distance of 255.1 pm are remarkable aspects of this feature. The mean bond lengths in the bicyclic compound were found to be d(Si? C) = 190.9 pm and d(Si? C) = 185.1 pm for exo- and endocyclic bonds, respectively. The skeleton of 10 is of the symmetry 2/m-C_2h. The six-membered chain is plane. The central C? C single bond length and the mean distance of the cumulated double bonds are 148.6 pm and 130.5 pm, respectively.