Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XLIII. Alkoholyse von Silicium-Schwefel-Verbindungen mit Alkoxyethanolen und 2-Mercaptoethanol

Contributions to the Chemistry of Silicon-Sulphur Compounds. XLIII. Alcoholysis Reaction of Silicon-Sulphur Compounds with Alkoxyethanols and 2-Mercaptoethanol The reactions of 2-alkoxyethanols und 2-mercaptoethanol with (RO)₃SiSH, (RO)₂Si(SH)₂, cyclo-[(t-BuO₂)SiS]₂, and SiS₂ were investigated. Besides of mixed esters of orthosilicic acid a new group of mixed trialkoxysilanethiols – (RO)₂(R′O)SiSH – was obtained. Informations about the hydrolytic splitting of the Si? S bond of these Si? S compounds were obtained by thiomercurimetric titration with HMB.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XXIII. Die Hydrolysereaktion der Silanthiole

Contributions to the Chemistry of Silicon-Sulphur Compounds. XXIII. The Hydrolysis Reaction of Silanethiols The kinetics of the hydrolysis reaction of silanethiols (RO)₃SiSH and R₃SiSH in dioxane-water solutions were investigated and the rate constants and the activation parameters evaluated. The mechanism of the reaction is discussed. The relationship between the structure of silanethiols and their reactivity are evaluated.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 44. Trialkoxysilylthioderivate der Permethylpolysilane

Contributions to the Chemistry of Silicon-Sulphur Compounds. 44. Trialkoxysilylthio Derivatives of Permethylpolysilanes By reaction of (RO)₃SiSH · NEt₃ (R = i-Pr, t-Bu) with α,ω-Cl₂(SiMe₂)_n (n = 1, 2, 3, 4, 6) or with 1-Cl(SiMe₂)_nMe (n = 2, 4) trialkoxysilylthio derivatives of polysilanes of the two series α,ω-(RO)₃SiS(SiMe₂)_nSSi(OR)₃ and 1-(RO)₃SiS(SiMe₂)_nMe have been prepared. Some properties of obtained new compounds were given. The resistance of the Si? S bond on protolytic splitting has been characterized by half-life times of the alcoholysis reaction.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XVI.Trialkoxythiosilanolate von Metallen der I. und II. Hauptgruppe der Elemente und Darstellung von reinen Trialkoxysilanthiolen

Contributions to the Chemistry of Silicon-Sulphur Compounds. XVI. Derivatives of Trialkoxysilanethiols with the Main Groups I and II Elements and Preparation of Pure Trialkoxysilanethiols Trialkoxysilanethiolates: (RO)₃SiSM^I and [(RO)₃SiS]₂M^II (R 7dbond; Me, i-Pr, s-Bu, t-Bu, s-Am; M^I ? Li, Na, K; M^II ? Ca, Sr, Ba) were prepared in reaction of trialkoxysilanethiols and metals. Hydrates and THF solvates of these salts can also be formed. From sodium trialkoxysilanethiolates pure thiols (i-PrO)₃SiSH and (s-BuO)₃SiSH were prepared.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 46 [1]. 29Si-NMR-chemische Verschiebungen von Trialkoxysilylthioderivaten der Permethylpolysilane

Contributions to the Chemistry of Silicon-Sulphur Compounds. 46. ²⁹Si-N.M.R. Chemical Shifts of Trialkoxysilylthio Derivatives of Permethylpolysilanes ²⁹Si-N.M.R. chemical shifts of trialkoxysilythio derivatives of permethylpolysilanes of the two series: α, ω-(RO)₃SiS(SiMe₂)_nSSi(OR)₃, n = 2, 3, 4, 6 and 1-(RO)₃SiS(SiMe₂)_nMe, n = 2, 4; R = i-Pr, t-Bu and also ³¹C-NMR shifts are given. The relationship of ²⁹Si-NMR chemical shift from the netto charge at the silicon atom q(Si) which value has been corrected according to the Sandorfy C quantum-chemical model is discussed. The greater reduction of the electron density at silicon in compounds with Si? X bond (X = S, P, Cl) has been explained by a conjugation of the lone of sulphur with the Si? X bonding pair.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. XXIX. 29Si-NMR-Untersuchungen

Contributions to the Chemistry of Silicon-Sulphur Compounds. XXIX. ²⁹Si-N.M.R. Investigations Three series of silicon-sulphur compounds (RO)₃SiSR′ (I), (i-PrO)_4?nSi(SEt)_n (II) and cyclic Si? S compounds (III) were prepared, some of them at the first time and their ²⁹Si-N.M.R. spectra were measured. In the series of trialkoxysilylthio derivatives (I) were the steric and inductive effects of the RO and R'S groups evaluated. In the series II were the ²⁹Si-N.M.R. chemical shifts related to the relative paramagnetic screening constants σ^* and netto charge at the silicon atom q(Si) using the EN-quantum-chemical model discussed. In the series III were the shift contribution of the (SiS)₂ and 1-sila-2,5-dithiacyclopentan rings determined.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 47 [1]. Über die protolytische Spaltung der Si?S-Bindung in Trialkoxysilanthiolen und Darstellung von Trialkoxyorganoxysilanen

Contributions to the Chemistry of Silicon-Sulphur Compounds. 47. On Protolytic Splitting of the Si? S Bond of Trialkoxysilanethiols and Preparation of Trialkoxyorganoxysilanes The conditions of the reaction of protolytic splitting of the Si? S bond of (RO)₃SiSH by alcohols or phenols were optimized by use of pyridine. Some new trialkoxyorganoxysilanes have been prepared. By kinetic measurements the relationship between the structure of phenol and reaction rate were elucidated. The role of pyridine in the reaction mechanism has been proposed as nucleophile catalysis.     

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.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 50 [1] Bis(triorganoxysilyl)polysulfide und die Struktur des Bis(tri-t-butoxysilyl)disulfids

Contributions to the Chemistry of Silicon-Sulfur Compounds. 50. Bis(triorganoxysilyl)-polysulfides and the Structure of Bis(tri-tert-butoxysilyl)disulfide Disilylated polysulfides (RO)₃SiS_nSi(OR)₃, R = i-Pr, tert-Bu, 2,6-Me₂C₆H₃, n = 2–5, were obtained by reaction of (RO)₃SiSNa with I₂ or S_nCl₂, respectively. The reaction of [(t-BuO)₃Si]₂S₂ with Ph₃SiH yielded the mixed sulfide (t-BuO)₃SiSSiPh₃ and with Ph₃P or Bu₃P, by extrusion of one sulfur atom, the [(t-BuO)₃Si]₂S. The X-ray crystal structure of [(t-BuO)₃Si]₂S₂ was determined. The S? S bond length is 209,2 pm, Si? S 213,2 pm. The mean value of the Si? S? S angle is 100,7°, and the torsion angle Si? S? S? Si ?127,6°.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 53. Die Struktur des 1,3-Dimethyl-1,1,3,3-Tetraphenyldisilthians

Contributions to the Chemistry of Silicon-Sulphur Compounds. 53. Structure of 1,3-Dimethyl-1,1,3,3-tetraphenyldisilthiane 1,3-Dimethyl-1,1,3,3-tetraphenyldisilthiane was obtained by an insertion reaction of sulphur with Ph₂ MeSiH. The compound crystallizes triclinically (P1 ; a = 1166.7; b = 1231.1; c = 988.6 pm; α = 113.23; β = 90.34; γ = 112.43°; Z = 2). The X-ray structure analysis shows a bent configuration of the molecule with Si? S? Si = 108.7°. The results are discussed together with the structures of hexaphenyldisilthiane and dimethyltetraphenyldisiloxane.     

Synthesis and Structural Studies of New (Triphenylphosphine)(trialkoxysilanethiolato)gold(I) Complexes

Compounds of general formula Au{SSi(OR)₃}(PPh₃), R = Prⁱ ( 1 ), Bu^s ( 2 ) or Bu^t ( 3 ), have been obtained by reaction of AuCl(PPh₃) with triethylammonium salts of respective silanethiols, (RO)₃SiSH. Molecular and crystal structures of 1 , 2 , and 3 have been determined by the single crystal X‐ray structural analysis. Compounds 1 and 2 are the first structurally characterized metal derivatives of hydrolytically unstable trialkoxysilanethiols (PrⁱO)₃SiSH and (Bu^sO)₃SiSH.     

Bildung siliciumorganischer Verbindungen. 89. Selektive Photobromierung von Si-methylierten Carbosilanen

Formation of Organosilicon Compounds. 89. Selective Photobromination of Si-methylated Carbosilanes A selective photobromination of the C atoms in the skeleton of Si-methylated carbosilanes is reported. (me₃Si? CH₂)₂Sime₂ reacts to me₃Si? CBr₂? Sime₂? CH₂? Sime₃ in good yields (me = CH₃); the second CH₂ group is considerably slower brominated. Photobromination of (me₂Si? CH₂)₃ consecutively yields a and b . Also from (me₂Si? CH₂)₄ the derivative with one CBr₂ group is accessible. Bromination of tertiary CH groups is highly preferred; this is shown by the selective formation of c . The C-bromination of SiBr-substituted carbosilanes is significantly more difficult; nevertheless (Brme₂Si)₂CH₂ selectively forms (Brme₂Si)₂CBr₂. Brme₂Si? CH₂? Sime₂? CH₂? Sime₃ forms Brme₂Si? CH₂? Sime₂? CBr₂? Sime₃, i. e., only the CH₂ group non-adjacent to SiBr is attacked. The formation of CHBr groups could not be detected. Higher temperatures and longer reaction times increase the formation of polymers.     

Trivalent-pentavalente Phosphorverbindungen/Phosphazene. IV. Darstellung und Eigenschaften neuer N-silylierter Diphosphazene

Trivalent-Pentavalent Phosphorus Compounds/Phosphazenes. IV. Preparation and Properties of New N-silylated Diphosphazenes Phosphazeno-phosphanes, R₃P = N? P(OR′) ₂ (R = CH₃, N(CH₃)₂; R′ = CH₂? CF₃) react with trimethylazido silane to give N-silylated diphosphazenes, R₃P = N? P(OR′)₂ = N? Si(CH₃)₃ compounds decompose by atmospherical air to phosphazeno-phosphonamidic acid esters, R₃ P?N? P(O)(O? CH₂? CF₃)(NH₂). Thermolysis of diphosphazene R₃P = N? P(OR′) ₂ = N? Si(CH₃)₃ (R = CH₃, R′ = CH₂? CF₃) produces phosphazenyl-phosphazenes [N?P(N?P(CH₃)₃)OR′] _n. The compounds are characterized by elementary analysis, IR-, ¹H_-, ²⁹Si-, ³¹P-n.m.r., and mass spectroscopy.     

Bildung siliciumorganischer Verbindungen. 109. Reaktionen vollhydrierter Carbosilane mit Lithiumalkylen

Formation of Organosilicon Compounds. 109. Reactions of Perhydrogenated Carbosilanes with Alkyl-Lithium Compounds Si-hydrogenated linear carbosilanes react with MeLi or nBuLi to give the Si-alkylated derivatives. In contrast to the Si-methylated derivatives of (H₃Si? CH₂)₂SiH₂ 1 and (H₃Si)₂CH₂ 2 and to (Me₂Si? CH₂)₃ no lithiation of CH₂ groups is observed. Such, 1 with nBuLi yields nBuH₂Si? CH₂? SiH₂? CH₂? SiH₃ 5 and (nBuH₂Si? CH₂)₂SiH₂ 6 . 2 reacts with nBuLi to give nBuH₂Si? CH₂SiH₃ 7 and (nBuH₂Si)₂CH₂ 8 besides of 1, 5 und 6 . The latter results from a cleavage of a Si? C bond in 2 Producing nBuSiH₃ and LiCH₂? SiH₃ which combines with 2 to 1 . Subsequently 1 forms 5 and 6 . No higher alkylated derivatives of 1 or 2 could be detected.     

Trivalent-pentavalente Phosphorverbindungen/Phosphazene. II. Synthese N-silylierter Phosphinimine

Trivalent-Pentavalent Phosphorus Compounds/Phosphazenes. II. Synthesis of N-silylated Phosphinimines N-silylated phosphinimines (RO)₃P?N? Si(CH₃)₃ (R = ? C₂H₅, ? C₂H₂F₃, i-C₃H₇, n-C₄H₉) and (R₂N)₃P?N? Si(CH₃)₃ (R = ? C₂H₅) have been prepared by reaction of trialkyl phosphites P(OR)₃ and Tris-(diethylamino)-phosphine P(NR₂)₃ with trimethylsilyl azide. The products were identified by analysis, IR-, ¹H-, ¹⁹F-, ²⁹Si-, ³¹P-n.m.r. and mass spectroscopy.     

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).     

Trivalent-pentavalente Phosphorverbindungen/Phosphazene. V. Darstellung,Eigenschaften und Reaktionen neuer Phosphonig- und Phosphinigsäureester

Trivalent-Pentavalent Phosphorus Compounds/Phosphazenes. V. Preparation, Properties, and Reactions of New Phosphonous- and Phosphinous Acid Esters Phosphonous diesters R? P(OR′)₂ (R ? CH₃, Ph and R′ ? CH₂? CF₃) have been synthetized by reaction of phosphonous dichlorides with 2, 2, 2-trifluoroethanol in the presence of a base. These diesters react with trimethyl(trimethylsilylimino)phosphorane, (CH₃)₃P?N? Si(CH₃)₃ by desilylation and N? P-linking to phosphinous acid esters (CH₃)₃P?N? P(OR′)R. The phosphinous acid esters react with methyl iodide to the quaternary salts [(CH₃)₃P? N? P(OR′)(R)CH₃]⁺I^?. The compounds are characterized by elementary analysis and spectroscopical methods.     

Bis(trimethylsilyl)-hypophosphit und Alkoxycarbonylphosphonigsäure-bis(trimethylsilyl)ester als Schlüsselsubstanzen für die Synthese von Organophosphorverbindungen

Bis(trimethylsilyl)hypophosphite und Alkoxycarbonylphosphonous Acid Bis(trimethylsilyl) esters as Building Blocks in Organophosphorus Chemistry The oxidation of pure bis(trimethylsilyl)hypophosphite ( BTH ) with chalcogenides forming (Me₃SiO)₂P(X)H (X = O, S, Se, Te) is described as well as its reactions with alkylhalides RX (X = Cl, Br, I) and Cl? C(O)OR (R = Me, Et, Bzl). By reaction with oxygen, sulfur, and selenium the alkoxycarbonylphosphonous acid bis(trimethylsilyl)esters form RO? C(O)? P(X)(OSiMe₃)₂ (X = O, S, Se) whereas with Cl? C(O)OR the bis(alkoxycarbonyl)-phosphinic acid trimethylsilylesters are obtained. After partial hydrolysis the resulting instable RO? C(O)? P(O)H(OSiMe₃) gives RO? C(O)? P(O)(OSiMe₃)? CH₂? NH? A? COOR′ (A = CH₂, CH₂CH₂, CHCH₃, CH₂CH₂SH, CHCH(CH₃)₂,…) when allowed to react with hexahydro-s-triazines of the aminoacid esters. Reactions of the alkoxycarbonyl-P-silylesters with NaOR or NaOH result in the corresponding mono-, di-, or trisodium salts. With mineral acids decarboxylation occurs, but H? P(O)(OH)? CH₂? NH? A? COOH can be obtained, too. The structure of the compounds described are discussed by their n.m.r. data.     

Bildung siliciumorganischer Verbindungen. 70 [1]. Reaktionen Si-fluorierter 1,3,5-Trisilapentane mit CH3MgCl und LiCH3

Formation of Organosilicon Compounds. 70. Reactions of Si-fluorinated 1,3,5-Trisilapentanes with CH₃MgCl and LiCH₃ F₃Si? CCl₂? SiF₂? CH₂? SiF₃ 3 reacts with meMgCl. (me = Ch₃ starting with a Si-methylation and not with a C-metallation as in the corresponding Si- and C-chlorinated compounds, e. g. (Cl₃Si? CCl₂)₂SiCl₂ [2]. A CCl-hydrogenation is observed too, which in the case of F₃Si? CCl₂? SiF₂? CHCl? SiF₃ 4 gives meS₃Si? CCl₂? Sime₂? CH₂? Sime₃. (F₃Si? CCl₂)_{2 5} reacts with meMgCl to form preferentially 1,2-Disilapropanes by cleaving a Si? Cbond. The isolation of F₃Si? CCl₂H and meF₂Si? CCl₂? SiF₂me allows to locate the bond where 5 is cleaved at the beginning of the reaction. With meLi 5 reacts to form mainly me₃Si? C?C? Sime₃, showing that in the reaction of meLi, being a stronger reagent than meMgCl, and 5 a C-metallation occurs, following the same mechanism as in the reaction with (Cl₃Si? CCl₂)₂)SiCl₂ [2]. The reaction conditions for the synthesis of Si-fluroinated and C-chlorinated 1,3,5-Trisilapentanes in a 0.1 mol scale are reported. N.m.r. data of all investigated compounds are tabulated.     

Dielectric properties of oligomers. VII. Low-molecular-weight propylene glycols

The dielectric properties of low-molecular-weight propylene glycols HO? [CH(CH₃)CH₂O]_n? H (n = 3, 4, 5) were investigated to clarify the effect of chain length on the dielectric properties. The measurement of dielectric constant and dielectric loss was carried out over the frequency range 30 Hz to 30 MHz at temperatures of ?20 to ?65°C. The static dielectric constants of these glycols are between 10 and 30, slightly smaller than values for the corresponding ethylene glycols of the same degree of polymerization. All of the Cole–Cole arcs, even that for pentapropylene glycol, can be represented by the empirical Davidson–Cole equation. The dielectric properties of homologous propylene glycols are compared with those for the ethylene glycols and are discussed in terms of the effects of chain length and intermolecular hydrogen bonds.