Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XXXIV. Das tetramere Silber(I)-Tri-tert-Butoxysilanthiolat

Contributions to the Chemistry of Silicon Sulfur Compounds. XXXIV. Tetrameric Silver(I)-tri-tert-butoxysilanethiolate Silver(I)-tri-tert-butoxysilanethiolate is formed as a tetramere by reaction of tritert-butoxysilanethiol with AgNO₃. The compound crystallizes as colourless triclinic plates and sublimes in vacuum at 170°C without decomposition. F.I. mass spectra shows only the mass of the tetrameric unit (m/e = 1 548), whereas this unit is observed in E.I. mass spectra with lower intensity. The ²⁹Si n.m.r. spectrum shows a remarkable splitting of the signal around ?68.54 ppm, which is explained by Si? Ag couplings. The central unit of the molecule is a nearly plane alternating Ag₄S₄ eight-membered ring with threefold bonded sulfur and twofold bonded silver atoms. Most important are the significant deviations from colinear S? Ag? S bonds (172.3°) resulting from shifts of the silver atoms toward the center of the eight-membered Ag₄S₄ ring (Ag? Ag = 313.5 pm). This effect is taken as a strong indication for high order direct Ag(I)-to-Ag(I) interactions. Related details of the structure are discussed. (Molecule symmetry is 2-C₂; space group P1 ; a = 1 769.7, b = 2012.8, c = 1 266.8 pm, α = 119.63°, β = 82.22°, γ = 95.08°; Z = 2; R = 0.067; 7 656 reflections h kl.)     

Acyl- und Alkylidenphosphane. XXVII [I.]. Molekül- und Kristallstruktur des Methyl[(N-phenyl,N-tri-methylsilyl)thiocarbamoyl]trimethylsilylphosphans

Acyl- and Alkylidenephosphines. XXVII. Molecular and Crystal Structure of Methyl-[(N-phenyl, N-trimethylsilyl)thiocarbamoyl]trimethylsilylphosphine . Methyl[(N-phenyl, N-trimethylsilyl)thiocarbamoyl]trimethylsilylphosphine 1a formed via an addition of methylbis(trimethylsilyl)phosphine to phenyl isothiocyanate [1], crystallizes in the monoclinic centrosymmetric space group P2₁/n with following dimensions of the unit cell determined at a temperature of measurement of ?80±3°C: a=1041.2(4);b=1706.9(12);c=1001.1(6)pm; β=106.41(4)°; Z = 4. An X-ray structure determination (R_w = 0.039) confirms the constitution of the compound as already derived from its nmr spectra. One trimethylsilyl group is bound to the phosphorus atom, whereas the other is connected with the sp²-hybridized nitrogen atom. Characteristic rounded bond lenghts and angles are: P? Si 231, P? CH₃ 184, P? C(S) 187, C?S 167, N? C(S) 137, and N? Si 181 pm as well as P? C? S 122°, P? C? N 117°, and S? C? N 121°.     

Beiträge zur Chemie der Silicium-Schwefelverbindungen. XXXVIII. Hexa-(tri-t-butoxy)disiloxan und Hexa-(tri-t-butoxy)disilthian

Contributions to the Chemistry of Silicon Sulfur Compounds. XXXVIII. Hexa(tri-t-butoxy)disiloxane and Hexa(tri-t-butoxy)disilthiane Hexa(tri-t-butoxy)disiloxane 1 and Hexa(tri-t-butoxy)disilthiane 2 were prepared by reaction of R₃SiONa with R₃SiCl and R₃SiSNa with R₃SiCl (R = tri-t-butoxy), respectively. The mass spectra show characteristic series of fragments. A large ²⁹Si n.m.r. chemical shift of about —103.55 ppm is observed with 1 , whereas the value of 2 is —75.99 ppm. The crystal structure analysis of 1 result first in a colinear molecule (Si? ;O? ;Si = 180°) with 1 symmetry and relative short mean bond lengths of about d(Si? ;O) = 155.6 pm, but with large and strong anisotropic ellipsoids. Their quantitative rigid body analyses yield decisive corrections, namely a bent molecule with an Si? ;O? ;Si angle of 144.0° and d?_corr = 163.5 pm. Molecule 2 is also bent as expected (Si? ;S? ;Si = 110.5°, d?(Si? ;S) = 211.9 pm and after rigid body correction 108.0° and d_corr = 215.2 pm, respectively). The results of our investigations will be discussed corresponding to the energy differences of the varying configurations at the bridging atoms.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XXXVI [1]. Das Quecksilber(II)-bis-tri-tert-butoxysilanthiolat

Contributions to the Chemistry of Silicon-Sulfur Compounds. XXXVI. Mercury(II)-bis-tri-tert-butoxysilanethiolate Mercury(II)bis-tri-tert-butoxysilanethiolate was obtained in reaction of HgO with (t-C₄H₉O)₃SiSH. This compound forms colourless triclinic plates. The central S? Hg? S bond element is linear, with Hg? S bond distance of 231.6 pm. The Hg atom is coordinated by two oxygens of the two butoxy groups, with Hg? O distance of 287.8 pm. The mean bond angle at the two-bonded sulfur is 95.6°. (Space group P1 ; a = 930.8, b = 944.0, c = 1204.8 pm, α = 100.34, β = 97,64, γ = 116.50°; Z = 1; R = 0.035; 3390 reflections hkl).     

Phosphaniminato-Komplexe des Iods. Synthese und Kristallstrukturen von Ph3PNIO2 und Ph3PNSiMe3 · I2

Phosphoraneiminato Complexes of Iodine. Syntheses and Crystal Structures of Ph₃PNIO₂ and Ph₃PNSiMe₃ · I₂ Ph₃PNIO₂ has been prepared as yellow crystals by the reaction of Ph₃PNSiMe₃ with I₂O₅ in boiling acetonitrile, whereas the molecular complex Ph₃PNSiMe₃ · I₂ is formed as brown crystals by the reaction of Ph₃PNSiMe₃ with iodine in acetonitrile solution. Both complexes were characterized by crystal structure determinations. Ph₃PNIO₂: Space group P2₁/n, Z = 4, 2 858 observed unique reflections, R = 0.039. Lattice dimensions at 19°C: a = 972.8(2), b = 1 743.4(3), c = 1 073.7(2) pm, β = 115.46(3)°. The compound forms monomeric molecules with pyramidal geometry at the iodine atom. The bond angle PNI (126.9°) is unusually small; the PN bond length of 159.2 pm corresponds with a double bond. Ph₃PNSiMe₃ · I₂: Space group P1 , Z = 2, 3 560 observed unique reflections, R = 0.033. Lattice dimensions at 19°C: a = 941.2(2), b = 1 041.7(2), c = 1 287.4(3) pm, α = 78.34(1)°, β = 72.00(2)°, γ = 86.08(2)°. The compound forms monomeric molecules, in which the I₂ molecule and the nitrogen atom of the phosphoraneimine molecule realize a linear N? I? I axis with a bond length N? I of 243.2 pm.     

Acyl- und Alkylidenphosphane. XXIII [1]. Synthese und Struktur der [Bis(trimethylsilylsulfano)methyliden]phosphane

Acyl- and Alkylidenephosphines. XXIII. Synthesis and Structure of [Bis(trimethylsilylsulfano)methylidene]phosphines Analogous to the phenyl derivative 1a [2] tert-butyl- 1b , mesityl- 1c and methylbis-(trimethylsilyl)phosphine 1 d react with carbon disulfide to give the corresponding [bis(trimethylsilylsulfano)methylidene]phosphines 4 . Only in case of the mesitylphosphine 1 c the intermediate compounds 2 and 3 could be detected by n.m.r. spectroscopic methods; thermally unstable [bis(trimethylsilylsulfano)methylidene]methylphosphine 4 d dimerizes rapidly [1]. [Bis(trimethylsilylsulfano)methylidene]phenylphosphine 4 a crystallizes in the monoclinic centrosymmetric space group P2₁/c with following dimensions of the unit cell determined at ?95 ± 3°C: a = 1386.4(8); b = 1036.0(7); c = 1281.7(8) pm; ß = 101.23(4)°; Z = 4. An X-ray structure determination (R = 0.032) proves the constitution of this compound as already derived from its nmr spectra. Characteristic bond lengths and angles are: P?C 170; P? C(phenyl) 183; C? S 176; S? Si 219 pm; C? P?C 107; P?C? S 124 and 120; S? C? S 116 and C? S? Si 111°.     

Darstellung,Eigenschaften und Kristallstruktur von [2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]acetylacetonatopalladium(II)

Synthesis, Properties, and Structure of [2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]-palladium(II) Acetylacetonate The reaction of Di-μ-chloro-bis[2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]palladium(II) with Thallium(I) acetylacetonate yields [2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]palladium(II) acetylacetonate. The complex crystallizes monoclinic in the space group P2₁/n with the lattice constants a = 1302.4(3), b = 836.0(2), c = 1341.3(3) pm, β = 93.69(3)°. Pd has a squareplanar coordination by two O atoms of acetylacetonate, the N atom of the imidazole ring, and the C atom of the phenyl group. I.r., n.m.r., and mass spectra are reported.     

Übergangsmetallphosphidokomplexe. VIII. Strukturuntersuchungen an Übergangsmetallphosphor-Vier- und Sechsringkomplexen. Die Strukturen von [(CO)4MnPH2]2, [(CO)4MnPH2]3 und [cpNiPH2]3

Transition Metal Phosphido Complexes. VIII. X-Ray Diffraction Studies of Transition Metal Phosphorus Four- and Six-Membered Ring Complexes. Structures of [(CO)₄MnPH₂]₂, [(CO)₄MnPH₂]₃, and [cpNiPH₂]₃ [(CO)₄MnPH₂]₂ 1 crystallizes triclinic in the space group P1 with a = 680.4 pm, b = 706.4 pm, c = 919.1 pm, α 110.5°, β = 91.92°, γ 115.65°, and Z = 1 formula unit. The molecule exhibits a centrosymmetrical structure. The bond angles within the planar four-membered (Mn? P)₂-ring are 76.1° at the Mn atoms and 103.9° at the P atoms, respectively. The average Mn? P bond distance is found to be 235.1 pm. [(CO)₄MnPH₂]₃ 2 crystallizes monoclinic in the space group P2/n with a = 905.2 pm, b = 974.8 pm, c = 1264.2 pm, β = 109.1°, and Z = 2 formula units. The framework of the six-membered (Mn? P)₃-ring can be described as having a twist boat conformation. The average endocyclic bond angles are with 89.1° at the Mn atoms and 130.1° at the P atoms, respectively, largely widened compared to 1 . The average Mn? P bond distance, which is found to be 238.5 pm, is also slightly increased compared to 1 . [cpNiPH₂]₃ 3 crystallizes rhombohedral in the space group R3. The cell constants (hexagonal setting) are a = b = 1686.1 pm, c = 561.1 pm and Z = 3 formula units. The six-membered (Ni? P)₃-ring exhibits a chair conformation. The endocyclic bond angles are with 92.3° at the Ni atoms and 124.3° at the P atoms, respectively, comparable with those of the six-membered ring compound 2 . The Ni? P bond distance is found to be 215.2 pm. The eyclopentadienyl ligands are disordered and have been refined as rigid groups.     

Cyclische Diazastannylene. XV [1]. Charakterisierung einer instabilen Zwischenstufe: 1,3-Di-tert-butyl-2,2-dimethyl-4-tert-butylammonium-1,3,2,4λ3-diazasilastannatetidin

Cyclic Diazastannylenes. XV. Characterization of an Unstable Intermediate: 1,3-Di-tert-butyl-2,2-dimethyl-4-tert-butyl-ammonium-1,3,2,4λ³-diazasilastannatetidine The primary step in the reaction of 1, 3-di-tert-butyl-2,2-dimethyl-1,3,2,4λ²-diazasilastannetidine ( 1 ) with tert-butylamine is the formation of the Lewis-acid-base adduct 5 . In 5 the electrophilic tin atom of 1 is coordinated by the nucleophilic nitrogen atom of the tert-butylamine. 5 crystallizes below ?110°C in a triclinic cell with dimensions (conventional cell see Table 2): a = 1034(4), b = 1492(5), c = 654(3) pm, α= 89.9(3), β = 96.8(3), γ = 91.6(3)°, Z = 2. Above ?110°C the triclinic phase of 5 can be transformed to a monoclinic one (space group P2₁/m) with cell dimensions a = 1048(3), b = 1513(4), c = 654(2) pm, β = 96.9(3)°, Z = 2. An X-ray structural investigation of the latter phase reveals the adduct 5 to have C_S(m)-point symmetry. Important molecular dimensions are the rather long donor bond Sn→N of 242(3) pm, the Sn? N distances within the ring of 211(2) pm and the trigonal pyramidal coordination of the tin atom with mean N? Sn? N angles of 82.3°. The nitrogen atoms of the ring are pyramidal disturbing the planarity of the ring by a bending of 12°. This geometry is due to intramolecular N? H contacts (～290 pm) of the amino-hydrogen atoms with the nitrogen atoms of the ring. Some conclusions for the reaction path can be drawn from the structure of 5 .     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XXXIX. Blei(II)-bis-tri-tert-butoxysilanthiolat

Contributions to the Chemistry of Silicon Sulfur Compounds. XXXIX. Lead(II)-bis-tritertbutoxysilanethiolate The title compound 1 is formed from (t-C₄H₉O)₃SiSH and PbO by an exothermic reaction. In benzene solution 1 is monomeric, whereas a solvated dimer the structure of which was determined crystallizes from glyme solutions. The F.I. mass spectrum only shows the mass of the monomeric unit. The ²⁹Si n.m.r. spectrum shows only one sharp signal at δ = ?68.33 ppm. The central four-membered (Pb₂S₂) ring of the dimer is puckered (butterfly; 51.2°). The folding takes place at the Pb atoms. The Pb atoms are threefold coordinated by S atoms (d_endo = 278.9 pm; d_exo = 258.6 pm) whereas the S atoms are bonded to two Pb atoms and one Si atom (208.8–214.3 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.     

Bildung siliciumorganischer Verbindungen. 96. Bildung und Struktur von P-Yliden des 1,3,5-Trisilacyclohexans (Einfluß der Substituenten)

Formation of Organosilicon Compounds. 96. Preparation and Structure of P-Ylides of the 1,3,5-Trisilahexanes (Influence of the Substituents) The influence of the substituents at the silicon atoms on formation and structure of ylides of 1,3,5-trisilacyclohexanesis investigated. The reactions of 1 , 2 , 3 with Me₃Si? PMe₂ lead via cleavage of the Si? P bond and subsequent rearrangement to the ylides 4 , 5 and 6 . The x-ray structure determination reveals, that the atoms of the ylid part of 4 are in a plane with the shortened bond distances d(C? P) = 168.6 pm and d(Si? C) = 180.1 pm, whereas the other endocyclic Si? C distances remain nearly unaffected by the ylid formation. Only the endocyclic bond angles C? Si? C of the Si atoms of the ylid are enlarged (116°). In the molecule 6 d(C? P) = 164.6 pm is much shorter, but d(P? Br) = 236.6 pm is enlarged. This enlargement is coupled with a deviation of 17 pm for the ylidic C atom from the ylid plane. Distances and angles are normal in the methylated trisilnhexane. The ring in 6 has boat conformation, in 4 a flat chair conformation.     

Polysulfonylamine. VII. Aliphatische Trisulfonylamine

Polysulfonyl Amines. VII. Aliphatic Trisulfonyl Amines The compounds N(SO₂R¹)₂(SO₂R²) with R¹ = R² = CH₃ ( 2a ), R¹ = R² = C₂H₅ ( 2b ) and R¹ = CH₃, R² = C₂H₅ ( 2c ) are prepared by cleavage of aminostannanes (CH₃)₃SnN(SO₂R¹)₂ with sulfonyl chlorides R²SO₂Cl. A simple synthesis of 2a from AgN(SO₂CH₃)₂ and CH₃SO₂Cl is described. From the vibrational spectra of 2a , evidence is obtained for a planar NS₃ group in this compound. X-ray structure determinations of 2b and HN(SO₂C₂H₅)₂ ( 3 ) are reported. In 2b , the NS₃ group is approximately planar (S? N? S bond angles 119.0 ± 0.6°, sum of bond angles at N 356.9°); the S? N bond lengths of ca. 173 pm indicate a bond order of 1. In compound 3 , the nitrogen atom has a planar coordination (S? N? S angle 125.3°, sum of bond angles at N 359.3°), the S? N bond lengths of ca. 165 pm correlate with a bond order of 1.3? 1.4.     

Phosphaniminato-Komplexe des Schwefels. Synthese und Kristallstrukturen von [O3SS(NPPh3)2] · CH3CN, [SO(NPPh3)2] und [SCl(NPMe3)2]Cl

Phosphorane Iminato Complexes of Sulfur. Syntheses and Crystal Structures of [O₃SS(NPPh₃)₂] · CH₃CN, [SO(NPPh₃)₂], and [SCl(NPMe₃)₂]Cl The title compounds have been prepared by the reaction of Me₃SiNPPh₃ with SO₂ and SOCl₂, respectively, and by the reaction of Me₃SiNPMe₃ with S₂Cl₂. They form colourless, moisture sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. [O₃SS((NPPh₃)₂)] · CH₃CN : Space group Pca2₁, Z = 4, structure solution with 4016 observed unique reflections, R = 0.050. Lattice dimensions at ?60°C: a = 1865.1, b = 1168.4, c = 1569.0 pm. The compound has a zwitterionic structure with a S? S bond length of 218.2 pm and bond lengths S? N of 161.2 and P? N of 160.1 pm. [SO(NPPh₃)₂] : Space group P2₁/c, Z = 4, structure solution with 2854 observed unique reflections, R = 0.113. Lattice dimensions at ?50°C: a = 1173.1, b = 1585.6, c = 1619.2 pm, b? = 98.13°. The compound forms monomeric molecules, in which the positions of S and N atoms are disordered in two positions. The bond lengths are S? N 166 pm and P? N 163 pm in average. [SCl(NPMe₃)₂]Cl : Space group P1 , Z = 2, structure solution with 2416 observed unique reflections, R = 0.038. Lattice dimensions at 20°C: a = 613.2, b = 1030.3, c = 1111.4 pm, α = 88.48°, b? = 88.01°, γ = 83.10°. The compound forms ions [SCl(NPMe₃)₂]⁺ and Cl^?. In the cation the sulfur atom is ?-tetrahedrally coordinated with a long S? Cl distance of 246.9 pm and bond lengths S? N of 155.3 pm and P? N of 164.3 pm in average.     

Die Schichtstruktur von Tl[CuAsO4] und Tl[CuPO4] mit Zwischenschichten aus Thallium(I) mit stereoaktivem Elektronenpaar

The Layer Structure of Tl[CuAsO₄] and Tl[CuPO₄] with Layers of Thallium(I) with Stereoactive Lone Pair Single crystals of Tl[CuAsO₄] and Tl[CuPO₄] were prepared by reaction of oxygen with Tl/Cu/As and Tl/Cu/P alloys, respectively. The new isotypic compounds crystallize in spacegroup C2/c with Z = 8 and lattice constants a = 684.70(7) pm, b = 712.64(5) pm, c = 1822.4(2) pm, β = 92.76(1)° for Tl[CuAsO₄] and a = 671.57(8) pm, b = 697.09(6) pm, c = 1789.1(2) pm, β = 93.12(1)° for Tl[CuPO₄]. Square planar [CuO₄]-units are connected by common corners to form undulated [CuO₃]₂-chains running along [010]. Interconnection of the chains by arsenate or phosphate groups results in the formation of anionic cuprate-arsenate- and cuprate-phosphate-slabs, respectively. Along [001] these slabs are alternating with double layers of thallium(I) ions in which the stereochemical activity of the Tl⁺ lone pair is apparent from an hemispheric coordination of thallium by oxygen. The structure is related to that of the orthorhombic form of KCuPO₄.     

Das 1,3,5,7-Tetraphospha-2,4,6,8,9-dekamethyl-2,4,6,8,9-pentasilabicyclo(3.3.1)-nonan. Struktur und Reaktionen

1,3,5,7-Tetraphospha-2,4,6,8,9-decamethyl-2,4,6,8,9-pentasila-bicyclo (3.3.1)-nonan. Structure and Reactions The structure of the title compound 1 (white quad-shaped crystals, mp. 193°C) obtained by reaction of Li₂PH with Me₂SiCl₂, is identified by ³¹PNMR and mass spectra as well as X-ray structure analysis. Compound 1 crystallizes in the monoclinic space group C2/c (No. 15) with a = 1563.6(28) pm, b = 1166.7(9) pm, c = 2556.0(27) pm, = 87.07(12)° and Z = 8 formula units in the elementary cell. The molecule has approximately mm (C_2v) symmetry. The boat-boat conformation characterizes 1 as direct precursor of the dodecamethyl-hexasila-tetraphospha-adamantane. The bond lengths and bond angles are normal with d?(P? Si) = 224.5 pm and d?(Si? Me) = 186.0 pm. The H bonded to P are directed exocyclic. 1 reacts with (CO)₄CrNBD (NBD = Norbornadiene) (bidentate ligand) to (SiMe₂)₅P₂(PH)₂Cr(CO)₄ 2 while closing the structure of compound 1 to the adamantane structure via the inserted Cr(CO)₄.     

[WCl4(Me3Si?CC?SiMe3)]2 Synthese,IR-Spektrum und Kristallstruktur

[WCl₄(Me₃Si? C?C? SiMe₃)]₂. Synthesis, I.R. Spectrum, and Crystal Structure The title compound is obtained from tungsten hexachloride and bis-trimethylsilyl acetylene in the presence of C₂Cl₄ in dichloro methane, forming green crystals. The complex is characterized by the mass spectrum, the i.r. spectrum, and by a structural analysis with the aid of X-ray diffraction data. [WCl₄(Me₃Si? C?C? SiMe₃)]₂ crystallizes triclinic in the space group P1 with one dimeric formula unit per unit cell (2 231 observed, independent reflexions, R = 4.6%). The cell dimensions are a = 928, b = 938, c = 1 080 pm; α = 115.3°, β = 91.9°, γ = 100.0°. The complex forms centrosymmetric dimers, the units being linked by chloro bridges of bond lengths W? Cl 244 and 272 pm. The trans-position to the long W? Cl bridge is occupied by the acetylene ligand which is bonded side-on with identical W? C bond lengths of 203 pm. Together with the three terminal chlorine ligands (mean W? Cl distance 231 pm) the tungsten atom achieves coordination number seven.     

Chelatkomplexe von Rheniumtetrachlorid. Die Kristallstrukturen von ReCl4(DME) und ReCl4(DPPE) · Tolan

Chelate Complexes of Rhenium Tetrachloride. The Crystal Structures of ReCl₄(DME) and ReCl₄(DPPE) · Tolan Bright green crystals of ReCl₄(DME) have been prepared by the reaction of rhenium pentachloride with dimethoxyethane (DME) in dichloromethane. ReCl₄(DPPE) · tolan was obtained in form of red crystals by the reaction of the alkyne complex [ReCl₄(Ph? C?C? Ph)(POCl₃)] with bis(diphenylphosphino)ethane (DPPE) in dichloromethane. The complexes were characterized by X-ray structure determinations. ReCl₄(DME): Space group I4 2d, Z = 8, 829 observed unique reflexions, R = 0.022. Lattice dimensions at 19.5°C: a = b = 960.60(6), c = 2337.2(6) pm. The complex forms monomeric molecules with DME as chelating ligand; the Re? O bond lengths are 213.1 pm. The chlorine atoms, arranged in trans position to the chelating ligand, have slightly shorter Re? Cl bonds than the chlorine atoms in cis position (232,1 pm). ReCl₄(DPPE) · tolan: Space group P2₁/n, Z = 4,4313 observed unique reflexions, R = 0.040. Lattice dimensions at ?80°C: a = 1095.7(1), b = 1764.2(2), c = 1898.0(2) pm, β = 99.229(8)°. The compound consists in form of monomeric molecules [ReCl₄(DPPE)] and diphenylacetylene molecules, which are incorporated in the lattice. The two phenyl rings of the tolan molecules are twisted towards each other along the C? C axis with a dihedral angle of 21°. The DPPE molecules are bonded to the rhenium atom in a chelating fashion with medium Re? P lengths of 250.4 pm. The chlorine atoms, arranged in trans position to this ligand, with Re? Cl bond lengths of 234.5 pm are slightly longer than the Re? Cl bonds in cis position with 232.3 pm.     

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.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XXX. Die Struktur des Tetra-t-butoxy-1,3,2,4-dithiadisiletans

Contributions to the Chemistry of Silicon-Sulfur Compounds. XXX. Structure of Tetra-t-butoxy-1,3,2,4-dithiadisiletane Alcoholysis of silicon disulfide by t-butanol yielded the title compound. [(t-BuO)₂SiS]₂ crystallizes orthorhombically in the space group Pbca (no. 61) with a = 1708.4(5), b = 1560.8(3), c = 907.1(3) pm and Z = 4 molecules per unit cell. The molecule has the crystallographic 1 –C_i point symmetry and consequently the Si₂S₂ four-membered ring is rigid plane. The bond distances of this ring are Si? S = 214.2 and 213.1 pm and the bond angles S? Si? S = 97.8° and Si? S? Si = 82.2°. Related details of the structure are discussed.