Bildung siliciumorganischer Verbindungen. 85 [1]. Bildung,Reaktionen und Struktur des 1,1,3,3-Tetramethyl-2,4-bis(trimethylsilyl)-1,3-disilabicyclo[1, 1, 0]butans

me₃Si? CCl₂?Sime₂Cl (me ? CH₃) läßt sich mit n-buLi (bu ? C₄H₉) bei–100°C (Lösungsmittel THF/Äther) in me₃Si? CCl(Li)? Sime₂Cl a überführen. das mit meJ me₃Si? CClme? Sime₂Cl bildet. Wird a in Abwesenheit eines Abfangreagenzes langsam erwärmt, so bildet sich unter Abspaltung von LiCl (Cl aus der SiCl-Gruppe) über eine reaktive Zwischenstufe des Bicyclobutans b . Die Struktur von b ist durch NMR-Untersuchung, Röntgenstrukturanalyse und Abbaureaktionen gesichert. Mit HBr bzw. CH₃OH werden die Si? C-Bindungen der Dreiringe in b gespalten, so daß sich me₃Si? CH₂? C(Sime₂X)₂Sime₃ (X ? Br, OCH₃) bildet. Formation of Organosilicon Compounds. 85. Formation, Reactions, and Structure of 1,1,3,3-Tetramethyl-2,4-bis(trimethylsilyl)-1,3-disilabicyclo[1, 1, 0]butane me₃Si? CCl₂? Sime₂Cl (me ? CH₃) with n-buLi (bu ? C₄H₉) at –100°C (solvent: THF/ether) yields me₃Si? CCl(Li)? Sime₂Cl a , which forms me₃Si? CClme? Sime₂Cl with meI. By warming a slowly in absence of any trapping reagent the bicyclobutane b is obtained via a reactive intermediate under elimination of LiCl (Cl from the SiCl group). The structure of b is established by nmr investigations, X-ray structure determination and chemical derivatisation.     

Bildung siliciumorganischer Verbindungen. LVIII. Die Synthese eines Carbosilans mit Propellan-Struktur

Formation of Organosilicon Compounds. LVIII. Synthesis of a Carbosilane with Propellane Structure 1 (· ? C resp. CH₂; x ? Si(CH₃)₂ resp. Si) is formed by a coupling reaction of BrSi(CH₂? Sime₂? CH₂? Sime₂Br)₃ 2 with CCl₄ and Li. The reaction of C₆H₅me₂Si? CH₂Li with Clme₂Si? CH₂Br leads to C₆H₅me₂Si? CH₂? Sime₂? CH₂Br. Metallation with lithium and succeeding reaction with Cl₃SiC₆H₅ produces compound C₆H₅Si(CH₂? Sime₂? CH₂? Sime₂C₆H₅)₃, which than forms 2 by cleavage with bromine.     

Amino-phosphane. X. Einige Additionsreaktionen von N-Diphenylphosphinotetraphenyldiphosphin-imid

Diphenylphosphorous chloride and methyl iodide add readily to the N-bonded P(III)-atom of (C₆H₅)₂P? P(C₆H₅)₃?N? P(C₆H₅)₂ forming the salts [(C₆H₅)₂P? P(C₆H₅)₂ N P(C₆H₅)₂? P(C₆H₅)₂]Cl and [(C₆H₅)₂P? P(C₆H₅)₂ N P(C₆H₅)₂. CH₃]I, respectively. A similar behaviour is observed with sulfur: Under mild conditions (C₆H₅)₂P? P(C₆H₅)₂?N? P(C₆H₅)₂ = S is formed but forcing conditions are required to produce S = P(C₆H₅)₂? P(C₆H₅)₂?N? P(C₆H₅)₂?S. The monosulfide is also obtained by treating (C₆H₅)₂P(S)N[Si(CH₃)₃]₂ with diphenylphosphorous chloride, indicating the favoured formation of the phosphazene system as compared with the phosphazane system Confirmation of the structures comes from ³¹P nmr and IR data, and for the sulfides also from their degradation with bromine.     

Silaheterocyklen. III. Erzeugung und Reaktivität von Di-tbutyl-Neopentylsilaethen,BuSiCHCH2But

Silaheterocycles. III. Synthesis and Reactivity of Di-^tbutylneopentylsilaethene, Bu Si?CHCH₂Bu^t The three di-^tbutylvinylsilanes BuSi(X)CH?CH₂ (X = H 5 , X = F 9 , X = Cl 22 ) are prepared by the reaction of their SiCl precursors with vinyl lithium. In the treatment with LiBu^t the first step is the generation of the α-lithio compound BuSi(X)CH(Li)CH₂Bu^t, the following reactions are governed by the nature of the substituent X and the reaction conditions (solvent, concentration, temperature). For X = H 2,3-LiH elimination leads to BuSi(H)CH?CHBu^t ( 7 ), with X = F or Cl Si?C formation by 1,2-LiX elimination competes with intermolecular Si-C-coupling producing BuSi(H)CH(SiBuCH?CHBu^t)CH₂Bu^t ( 13 ) as the main product. BuSi?CHCH₂Bu^t ( 1 ) probably coordinates to LiBu^t and reacts to yield BuSiCH?CHBu^t ( 3 ) and 7 , forms tetrabutyl-dineopentyl-1,3-disilacyclobutane 2 by cyclodimerization and 13 by addition of BuSi(X)CH(Li)CH₂Bu^t.     

Studies on polyyne polymers containing transition metals in the main chain. IV. Polymer synthesis by oxidative coupling of transition metal-bis(acetylide) complexes

The metal-polyyne polymers consisting of transition metals and conjugated tetrayne systems where M represents ? Pt(PBu₃)₂? or ? Pd(PBu₃)₂? moiety were prepared by the oxidative coupling method and characterized by spectral analysis, associated with novel depolymerization giving binuclear transition metal complexes, and      

Versuche zur Darstellung von zweifach silyliertem Nitramid

Experiments for the Preparation of Doubly Silylated Nitroamine Silylated derivatives of nitroamines can be obtained by treating nitryl compounds with silazanes, i. e. via formation of an N? N bond: The reaction product can be isolated in the case of R ? CH₃, R′? Si(CH₃)₃, whereas [(CH₃)₃Si]₂ NNO₂ is unstable and cannot be obtained at room temperature. Isomeric Bis(trimethylsilyl)-hyponitrite formed by reaction of silver hyponitrite with trimethylchlorosilane is similarly unstable. Cleavage of siloxanes by nitryl and nitrosyl compounds is discussed in connection with the above reaction.     

Dendronized Polymers via Macromonomer Route in Supercritical Carbon Dioxide

Radical polymerizations from third to fifth generation macromonomers were conducted in supercritical carbon dioxide (scCO₂). It was found that all monomers were not soluble in such a medium, and reactions occurred in the CO₂‐swollen monomer matrices. Despite the expected severe diffusion limitations, very high conversions and molecular weights were obtained. It is believed that the plasticization effect induced by the CO₂ plays a key role in these surprising findings. Scanning force microscopical analyses confirmed that mainly linear dendronized polymers were obtained and therefore chain transfer to polymer is virtually irrelevant.

     

Synthesis of trifluoromethyl‐1,2,4‐triazine‐ and trifluoromethylpyrimidine‐fused uracils

A variety of trifluoromethyl‐1,2,4‐triazine‐ and trifluoromethylpyrimidine‐fused uracils ( 9 ), ( 12 ), ( 15 ) and ( 18 ) were synthesized from trifluoroacetaldehyde ethyl hemiacetal or trifluoroacetic anhydride and corresponding uracil derivatives.     

Spirocyclische Titanamide mit der Diphenylsila-titanadiazacyclobutan- Baueinheit. Kristall- und Molekülstruktur von Ti[(NSiMe3)2SiPh2]2 [1]

Durch Umsetzung der N-lithiierten Silylamine Ph₂Si(NHR)₂ mit SiCl₄ bzw. TiBr₄ wurden die spirocyclischen Amide B (R = Me, Et, i-Pr) und C (R = i-Pr, Me₃Si) dargestellt und ihre Konstitution durch Analysen, ¹H- und ²⁹Si-NMR-Spektren gesichert. Von C, R = Me₃Si, wurde an einem Einkristall eine Röntgenstrukturanalyse durchgeführt. Wichtige Strukturdaten sind: TiN 1,918(2) Å, SiN endocycl. 1,750(2) Å, exocycl. 1,738(2) Å, ? SiNTi 90,3(1)°. Spirocyclic Titanium Amides Containing the Diphenylsila-titana-diazacyclobutane Fragment. Crystal and Molecular Structure of Ti[(NSiMe₃)₂SiPh₂]₂ By reaction of the N-lithiated silylamines Ph₂Si(NHR)₂ with SiCl₄ and TiBr₄, the spirocyclic amides B (R = Me, Et, i-Pr) and C (R = i-Pr, Me₃Si) respectively have been prepared. Their constitutions have been confirmed by elemental analyses and by ¹H and ²⁹Si nmr spectroscopy. C, R = Me₃Si, has been investigated by a single crystal x-ray structure analysis. Important structural parameters are: TiN 1.918(2) Å, SiN endocycl. 1.750(2) Å, exocycl. 1.738(2) Å, ? SiNTi 90.3(1)°.     

Trimethylsilylverbindungen der Vb-Elemente. VII. Die Kristallstrukturen von Lithium-bis(trimethylsilyl)bismutid · DME und Tetrakis(trimethylsilyl)dibismutan sowie Bemerkungen zur Kristallstruktur des Bis(4-methoxyphenyl)ditellans

Trimethylsilyl Derivatives of Vb Elements. VII. Crystal Structures of Lithium Bis(trimethylsilyl)bismuthide · DME and of Tetrakis(trimethylsilyl)dibismuthane as well as Some Comments on the Crystal Structure of Bis(4-methoxyphenyl)ditellane Colourless lithium bis(trimethylsilyl)bismuthide · DME

1 1,2-Dimethoxyethan (DME); Tetrahydrofuran (THF)

1 and green, metallic lustrous tetrakis(trimethylsilyl)dibismuthane 2 crystallize isotopic to their antimony homologues [1, 2]. As it is shown by crystal structure determinations { 1 : ?90°C; I 4 2d; a = 1017,3(4); c = 3738,0(26) pm; Z = 8; R _w = 0,065; 2 : + 20°C; P2 ₁ /c; a = 680,9(4); b = 1704,8(13); c = 1197,9 (10) pm; β = 119,46(6)°; Z = 2; R _w = 0,084} both compounds form chains which in the case of bismuthide 1 are built up as screws of alternating bismuth and lithium atoms; bonding further to two trimethylsilyl groups or to the chelating DME ligand both atoms gain coordination number 4 {Li? Bi 292(3); Bi? Si 263.3(14) pm; Bi? Li? Bi 132(1); Li? Bi? Li 148(1); φ(Li? Bi? Li? Bi) 83°}. In the case of dibismuthane 2 the centrosymmetric molecules are strung, their Bi-Bi groups forming nearly linear zigzag chains with shortened intermolecular contact distances {Bi-Bi 303.5(3); Bi …? Bi 380.4(3); Bi? Si 268 pm; Bi? Bi …? Bi 169; Bi? Bi? Si 97.4(5) and 92.0(5)°}. Structure and properties of 2 are compared with those of similar compounds; the crystal structure of brown, green metallic lustrous bis(4-methoxyphenyl)ditellane 5 already published by Ludlow and McCarthy[3] is reinvestigated with respect to very short intermolecular Te…?Te contacts.     

Silicium-Komplexe. VI. Oxalato-silicate und Oxalato-germanate

Silicon complexes. VI. Oxalatosilicates and oxalatogermanates By reaction of SiCl₄(GeCl₄) or diaryldichloro silanes (germanes) with Ag₂C₂O₄ and quartary ammonium or phosphonium iodides, compounds of the following formulas were prepared: These products are resistant towards hydrolysis and were characterized by IR-spectra, conductivity and thermal decomposition. The compounds resulting from reaction of monoorganitrichloro silanes nearly correspond to the formula and are extremely sensitive towards hydrolysis.     

Synthese „anorganischer”︁ Tintenfisch-Moleküle

Inorganic Pode-Type Molecules The reaction of monosubstituated polyethylenglykoles [m = 0—4, R = Cl, OCH₃, OAs(CH₃)₂, OSi(CH₃)₃] with amino compounds (CH₃)_xE[N(CH₃)₂]_y(E = Si, x = y = 2; E = Si, x = 1, y = 3; E = P, x = 0, y = 3; E = As, y = 0, y = 3) results in the formation of pode-type molecules of the formula . The synthesis and rearrangement of these compounds by heating is described.     

Radical Polymerization of the Silene (Me3Si)2SiCR2 by Hydrogen Transfer from a Trimethylsilyl Group

The silene (Me₃Si)₂Si?Ad is polymerized to produce a polycarbosilane with an unusual Si? Si? C repeating backbone, rather than the Si? C or Si? Si? C? C units expected for olefinic radical polymerization. The polymer structure and the polymerization mechanism (see scheme) were studied by GPC, EPR, and NMR spectroscopy and by trapping experiments.

     

Carbosilylierte Phospha-alkene

Carbosilylated phospha-alkenes Lithium-tris-trimethylsilylmethanide, (Me₃Si)₃C-Li, reacts with various organodichlorophosphines to give tris-(trimethylsilyl)-methyl-organochlorophosphines, the termal treatment of which under elimination of trimethylchlorosilane results in formation of the title compounds of the general formula B . NMR-data as well as the synthesis of compounds A and B will be discussed.     

Structure and Reactivity of a Unique Y‐Shaped Tricoordinate Bis(silyl)platinum(II)–NHC Complex

Y not? A unique, three‐coordinate Y‐shaped bis(silyl)platinum(II) complex was isolated and characterized (see structure; C light gray, N blue, Si pink, Pt dark gray). DFT studies on a model system shed light on the nature of this unusual coordination mode for platinum(II).

     

Die Strukturen der Heptahetero-Nortricyclene P7(Sime3)3 und P4(Sime2)3

The Structures of the Heptahetero-Nortricyclenes P₇(Sime₃)₃ and P₄(Sime₂)₃ Tris(trimethylsilyl)heptaphospha-nortricyclene P₇(Sime₃)₃ 1 and Hexamethyl-trisila-tetraphospha-nortricyclene P₄Si₃me₆ 2 are structural analogons to the hetero-nortricyclenes P and P₄S₃. 1 crystallizes in the space group P2₁ with a = 965.7 pm, b = 1746.5 pm, c = 693.3 pm, β = 99.61° and Z = 2 formula units. In the P₇ system tge P? P bond lengths differ functionally, namely 221.4 pm in the three-membered ring, 219.2 pm at the ring atoms and 217.9 pm at the bridgehead atom. The P? Si and Si? C bond lengths are 228.8 pm and 187.8 pm respectively. 2 crystallizes in the space group R3 with a_R = 1129.3 pm, α_R = 50.01° (hexagonal axes: a = 954.7 pm, c = 2956.9 pm) and Z = 2 formula units. In the P₄Si₃ systems the bond lengths are P? P = 220.2 pm, P? Si = 228.3 pm and 224.7 pm (to the bridgehead atom). The Si? C bond lengths are 187.3 pm. The structures are discussed with related compounds.     

CsCu4S3 und CsCu3S2: Sulfide mit tetraedrisch und linear koordiniertem Kupfer

Thermodynamics of the System Si? Cl? H By static and dynamic methods the equilibria 4SiHCl₃,g = 3SiHCl₄,g + Si,s + 2H₂,g (1) between 800 and 1140 K and SiCl₄,g + H₂,g = SiHCl₃,g + HCl,g (2) between 1170 and 1450 K were investigated. The expression for the temperature dependence of the equilibria were found to be lg Kp [Torr] = (5.688–1520/T) ± 0.32 (1) and lg Kp = (1.38/3250/T) ± 0.16 (2). The values measured for reaction pressures and equilibrium constants lead to the conclusion, that the difference of enthalpies of formation of SiCl₄ and SiHCl₃ found in literature is nessecarily to be corrected by 5–6 kcal/mole. With ΔH(SiCl₄,g) = ?157.1 kcal/mole the equilibrium measurements lead to the enthalpy of formation for SiHCl₃,g of ΔH(SiHCl₃,g) = ?118.2 kcal/mole.     

The photochemistry of hexafluoroacetylacetone in the vapour phase. Occurrence of a novel HF elimination reaction

Photolysis of the vapour of hexafluoroacetylacetone HFAA in its enolic form involves decomposition by two independent primary processes, one of which is a novel elimination of HF giving 2,2-difluoro-2,3-dihydro-5-trifluoromethylfuran-3-one: The HF is not vibrationally excited. Photolysis of the cyclic product of reaction (5) yields CF₂ radicals which, if HFAA is present, undergo an insertion into the enolic OH bond, (9) The infrared, ultraviolet, nuclear magnetic resonance, and mass spectra of HFAA and of the products of reactions (5) and (6) have been measured. Approximate quantum yields for reactions (1) and (5) have been obtained. Both ?₁ and ?₅ depend on pressure and the ratio ?₁/?₅ increases with temperature and decreased wavelength of photolysing light. It is proposed that the ratio ?₁/?₅ increases as the vibrational energy of electronically excited HFAA increases.     

Synthesis and psychotropic properties of furyl- and thienyl-germatranes

Trihalogermyl-furans and -thiophenes were prepared by inserting germanium dibromide (GeBr₂) generated from the dibromogermane(II) dioxanate complex into the carbon-halogen bond of halo-furans and -thiophenes. Their ethanolysis and transesterification by triethanolamine yielded the germatranes which were subjected to psychotropic activity assays. The psychotropic properties of germatranes were found to depend on the type of the heterocycle and on the position of the germatrane moiety.     

Perfluorovinyl Morpholine and Perfluorovinyl Pyrrolidine with Nucleophiles and Electrophiles

In this study, both monofunctional and bifunctional nucleophiles, as well as the electrophile FNO, are reacted with perfluorovinyl amines. The perfluorovinyl amines CF?CF₂ and CF?CF₂ have been reacted with dimethylamine and diethylamine in the presence of small amounts of water to give CHFC(O)N(CH₃)₂ ( 1 ), CHFC(O)N(CH₃)₂ ( 2 ), and CHFC(O)N(C₂H₅)₂ ( 3 ). With perfluorovinyl pyrrolidine and perfluorovinyl morpholine, ethanolamine gives the cyclized products CHF ( 4 ) and CHF ( 5 ), respectively. Reaction of the vinyl amines with (CH₃)₃SiOCH₂CF₃ in the presence of catalytic amounts of CsF results in the formation of cis- ( 6 ) and trans- ( 7 ) CF?CF(OCH₂CF₃) and cis- ( 8 ) and trans- ( 9 ) CF?CF(OCH₂CF₃). The electrophile FNO reacts slowly with perfluorovinyl pyrrolidine and perfluorovinyl morpholine, and more rapidly with (CF₃)₃CCF?CF₂ to give CF(NO)CF₃ ( 10 ), CF(NO)CF₃ ( 11 ) and (CF₃)₃CF(NO)CF₃ ( 12 ), respectively. Single crystal X-ray analysis is used to confirm the identity of the product obtained from the controlled hydrolysis of the sultone of perfluorovinyl pyrrolidine as the sulfonic acid anhydride C(O)CF₂OS(O)₂OCF₂C(O) ( 13 ). The X-ray crystal structure of perfluorosuccinic acid monohydrate ( 14 ), which is obtained when the perfluorovinyl pyrrolidine sultone is hydrolyzed in excess water, is also reported for the first time.