Bildung siliciumorganischer Verbindungen. 111. Die Hydrierung Si-chlorierter,C-spiroverbrückter 2,4-Disilacyclobutane mit LiAlH4 und iBu2AlH. Der Zugang zum Si8C3H20

Formation of Organosilicon Compounds. 111. The Hydrogenation of Si-chlorinated, C-spiro-linked 2,4-Disilacyclobutanes with LiAlH₄ or iBu₂AlH. The Access to Si₈C₃H₂₀ The hydrogenation of Si-chlorinated, C-spiro-linked 2,4-disilacyclobutanes containing C(SiCl₃)₂ terminal groups with LiAlH₄ in Et₂O proceeds under complete cleavage of the fourmembered rings and under elimination of one SiH₃ group. Such, Si₈C₃Cl₂₀ 4 forms (H₃Si)₂CH? SiH₂? CH(SiH₃)? SiH₂? CH(SiH₃)₂ 4 α, and even Si₈C₃H₂₀ 4a with LiAlH₄ forms 4 α. The hydrogenation of related compounds containing however CH(SiCl₃) terminal groups similarly proceeds under ring cleavage but no SiH₃ groups are eliminated. Such, (Cl₃Si)CH(SiCl₂)₂CH(SiCl₃) 41 forms (H₃Si)₂CH? SiH₂? CH₂(SiH₃) 41 α. However, in reactions with iBu₂AlH in pentane neither the disilacyclobutane rings are cleaved nor are SiH₃ groups eliminated. Only by this method Si₈C₃H₂₀ is accessible from 4 , Si₆C₂H₁₆ 3a from Si₆C₂Cl₁₆ 3 and Si₄C₂H₁₂ 41a from 41 . C(SiCl₃)₄ cleanly produces C(SiH₃)₄. Based on the knowledge about the different properties of LiAlH₄ and iBu₂AlH in hydrogenation reactions of disilacyclo-butanes it was possible to elucidate the composition and the structures of the hydrogenated derivatives of the product mixture from the reaction of MeCl₂Si? CCl₂? SiCl₃ with Si(Cu) [1] and to trace them back to the initially formed Si chlorinated disilacyclobutanes Si₆C₂Cl₁₅Me 34 , Si₆C₂Cl₁₄Me₂ 35 , Si₈C₃Cl₁₉Me 36 and Si₈C₃Cl₁₈Me₂ 37 . Compound 4a forms colourless crystals of space group P1 with a = 799.7(6), b = 1263.6(12), c = 1758.7(14) pm, α = 103.33(7)°, β = 95.28(6)°, γ = 105.57(7)° and Z = 4.     

Determination of hydrazides and 1,2-diacylhydrazines of aliphatic carboxylic acids by conductometric titration

A procedure is developed for the conductometric titration of hydrazides and 1,2-diacylhydrazines of aliphatic carboxylic acids with HCl or KOH in nonaqueous and water-alcohol solutions. The procedure is suitable for the determination of the major substance in hydrazides of C₅H₁₁-C₁₂H₂₅ aliphatic carboxylic acids and CH₃-C₇H₁₅ 1,2-diacylhydrazines and for the analysis of reaction mixtures containing N₂H₄, RCOOH, and RCOOH · N₂H₄ along with the major substance.     

Bildung siliciumorganischer Verbindungen. XXXIX. Teilchlorierte Carbosilane

1. Photochlorination in CCl₄ of the Si-chlorinated carbosilanes (Cl₃Si? CH₂)₂SiCl₂ and (Cl₂Si? CH₂)₃ leads to totally chlorinated compounds, e. g. (Cl₃Si? CCl₂)₂SiCl₂. After chlorination has started at one CH₂ group, formation of a CCl₂ group is preferred before another CH₂ group is involved into the reaction. Thus preparation of compounds a, b, c is possible. Cl₃Si? CCl₂? SiCl₂? CH₂? SiCl₃ (a) for (b) and (c) (see “Inhaltsübersicht”). SO₂Cl₂ (benzoyl peroxide) as chlorinating agent reacts more slowly, and opens an access to carbosilanes containing CHCl groups such as (d), Cl₃Si-CHCl? SiCl₂? CH₂? SiCl₃ (e). Reactions of compounds (a) to (d) with LiAlH₄ yields carbosilanes with SiH groups, and partially chlorinated C atoms. 2. By the high reactivity of Si? CCl₂? Si groups an exchange of Cl atoms of CCl groups in perchlorinated carbosilanes is possible for H atoms of Si? H groups in perhydrogenated carbosilanes, thus allowing the preparation of compounds containing CHCl and SiHCl groups, e. g. according to Gl.(1) (Inhaltsübersicht). Further reactions, formulated as the last equations in Inhaltsübersicht, are reported as well as the rearrangement of H₃Si? CHCl? SiH₃.     

Silicon–oxygen bonding on diphenylsilane through palladium(II)‐catalysed reactions

The reactions of phenols with diphenylsilane are catalysed by palladium(II) catalysts such as Pd(TMEDA)Cl₂ (TMEDA = tetramethylethylenediamine), Pd(DEED)Cl₂ (DEED = N,N′‐diethylethylenediamine), Pd(TEEDA)Cl₂ (TEEDA = N,N′‐tetraethylethylenediamine) or PdCl₂ to form hydrated silanols with molecular formula Ph₂Si(OR)OH·nH₂O (when R = C₆H₅, n = 3; when R = p‐CH₃C₆H₄ or o‐CH₃C₆H₄, n = 1). The reaction of hydroquinone with diphenylsilane in the presence of catalytic amounts of Pd(TMEDA)Cl₂ forms an Si–O‐bonded hydrated aggregate of composition [(C₆H₅)₂Si(OC₆H₄O).0.5H₂0] _n. p‐Benzoquinone reacted with diphenylsilane in the presence of a catalytic amount of Pd(TMEDA)Cl₂ and the reaction proceeded via a multiple pathway involving quinhydrone as an intermediate charge‐transfer complex which reacted further with diphenylsilane to give a linear siloxane. Copyright ­© 2000 John Wiley & Sons, Ltd.     

Phenyl(acyloxy)fluorosilanes C6H5Si(OCOR)nF3?n (n = 1, 2) and phenyl(acyloxy)fluorochlorosilanes C6H5Si(OCOR)FCl

The method of synthesis of the hitherto unknown class of organosilicon compounds, phenyl(acyloxy)fluorosilanes C₆H₅Si(OCOR) _n F_3−n (n = 1, 2) and phenyl(acyloxy)fluorochlorosilanes C₆H₅Si(OCOR) FCl in up to 91% yield has been developed based on the reaction of phenyl(fluoro)chlorosilanes C₆H₅SiCl _n F_3−n (n = 1, 2) with trimethylsilyl esters of carboxylic acids Me₃SiOC(O)R [R = H, CH₃, CF₃, CCl₃, ClCH₂, BrCH₂, CH₂=CHCH₃, CH₂=CHPh, CH(CH₃)=CH₂, Ph].     

Bildung siliciumorganischer Verbindungen. 110. Reaktionen von (Cl3Si)2CCl2, seiner Si-methylierten Derivate,von (Cl3Si)2CHCl, (Cl3Si)2C(Cl)Me und Me2CCl2 mit Silicium (Cu-Kat.)

Formation of Organosilicon Compounds. 110. Reactions of (Cl₃Si)₂CCl₂ and its Si-methylated Derivatives as well as of (Cl₃Si)₂CHCl, (Cl₃Si)₂C(Cl)Me and Me₂CCl₂ with Silicon (Cu cat.) The reactions of (Cl₃Si)₂CCl₂ 1 , its Si-methylated derivatives (Me₃Si)₂CCl₂ 8 , Me₃Si? CCl₂? SiMe₂Cl 9 , (ClMe₂Si)₂CCl₂ 10 , Me₃Si? CCl₂? SiMeCl₂ 11 , Cl₂MeSi? CCl₂? SiCl₃ 12 as well as of (Cl₃Si)₂CHCl 38 , (Cl₃Si)₂CClMe 39 and of Me₂CCl₂ with Si (Cu cat.) in a fluid bed reactor ( 38 and 39 also in a stirred solid bedreactor) arc presented. While (Cl₃Si)₂CCl₂ 1 yields C(SiCl₃)₄ 2 the 1,1,3,3-tetrachloro-2,2,4,4-tetrakis(trichlorsilyl)-1,3-disilacyclobutane Si₆C₂Cl₁₆ 3 and the related C-spiro linked disilacyclobutanes Si₈C₃Cl₂₀ 4 , Si₁₀C₄Cl₂₄ 5 , Si₁₂C₅Cl₂₈ 6 , Si₁₄C₆Cl₃₂ 7 this type of compounds is not obtained starting from the Si-methylated derivatives 8, 9, 10, 11 They Produce a number of variously Si-chlorinated and -methylated tetrasila- and trisilamethanes. However, Cl₂MeSi? CCl₂? SiCl₃ 12 forms besides of Si-chlorinated trisilamethanes also the disilacyclobutanes Si₆C₂Cl₁₅Me 34 and cis- and trans Si₆C₂Cl₁₄Me₂ 35 as well as the spiro-linked disilacyclobutanes Si₈C₃Cl₁₉Me 36 , Si₈C₃Cl₁₈Me₂ 37 . (Cl₃Si)₂CHCl 38 mainly yields HC(SiCl₃)₃ 31 and also the disilacyclobutanes cis- and trans-(Cl₃Si)HC(SiCl₂)₂CH(SiCl₃) 41 and (Cl₃Si)₂C(SiCl₂)₂CH(SiCl₃) 45 the 1,3,5-trisilacyclohexane [Cl₃Si(H)C? SiCl₂]₃ 44 as well as [(Cl₃Si)₂CH]₂SiCl₂, and (Cl₃Si)₂CClMe 39 mainly yields (Cl₃Si)₂C?CH₂and (Cl₃Si)₂besides of HC(SiCl₃)₃, MeC(SiCl₃)₃and (Cl₃Si)₃C? SiCl₂Me.,. Me₂CCl₂ 59 mainly yields Me(Cl)C?CH₂, Me₂CHCl and HCl₂Si? CMe₂? SiCl₃, besides of Me₂C(SiCl₃)₂ and Me₂C(SiCl₂H)₂ Compound 3 crystallizes triclinically in the space group P1 (Nr. 2) mit a = 900,3, b = 914,0, c = 855,3 pm, α = 116,45°, β = 101,44°, γ = 95,86° and one molecule per unit cell. Compound 4 crystallizes monoclinically in thc space group C2/c (no. 15) with a = 3158.3,b = I 103.7, c = 2037.4 pm, β = 1 16.62° and 8 molecules pcr unit cell. The disilacyclobutane ring of compound 3 is plane, showing a mean distance of d (Si-C) =19 1.8 pm and the usual deformations of endocyclic angles: α_Si = 94,2°> 85,8° = α_C.The spiro-linked disilacyclobutane rings of compound 4 are slightly folded by a mean angle of (19.0°). Their mean distances were found to be d (Si? C) = 190.4 pm relating to the central carbon atom and 192.0 pm to the outer ones, respectively. The deformations of endocyclic angles: α_Si = 93,9°> 84,4° = α_C are comparable to those of compound 3.     

Binuclear organometallic compounds VIII. Oxidative addition of Si-H or Si-Cl compounds to low valent Fe, Co, or Ni complexes stabilised by mono- or bi-dentate phosphines

The reactions of [(Ph₃P)₄Ni], [(Ph₃P)₃CoN₂], [(dp)₂Ni], [(dp)₂CoH], [(dp)₂Fe(C₂H₄)] or [(dp)₂FeH₂] (dp = Ph₂PCH₂CH₂Ph₂P) with Ph_nSiCl_4-n (n = 1, 2, or 3), Ph_nSiH_4-n, X₃SiH (X = Cl or Et), or R₂ClSiH (R = Ph or Me) have been investigated. Solid complexes were isolated which, for the most part, were insoluble in non-polar solvents. Assignments of structures are therefore incomplete, and are based on microanalysis, IR spectra, analogies with established reactions, and (in some cases) chemical degradation. Evidence is presented for the following: (i) for Ni^II, products from [(Ph₃P)₄Ni] and HSiXX′X″ (XX′X″ = Ph₃, Ph₂H or PhH₂), the cyclic [(Ph₃P)₂NiSiCl₂]₂, and the five-coordinate [(dp)₂-NiX]⁺[SiCl₃]^- (X = H or Cl₃Si); (ii) for Co^III, the six-coordinate cis-octahedral [(dp)₂CoH₂]⁺ [SiXX′X″]^- (XX′X″ = Cl₃, Cl₂Me, ClMe₂, or ClPh₂); and for Fe^II, the four-coordinate [(dp)FeH(SiCl₃)] and the six-coordinate [(dp)₂Fe(X)SiCl₃] (X = H, Cl, or Cl₃Si).     

Salze von Halogennophosphorsäuren. VII Darstellung und Eigenschaften von Siliciumdichlorphosphaten

Salts of Halogenophosphoric Acids. VII. Preparation and Properties of Silicon Dichlorophosphates By reaction of SiCl₄ or SiHCl₃ with dichlorophosphoric acid the compounds H[Si(PO₂Cl₂)₅] · C₂H₅OC₂H₅, H[Si(PO₂Cl₂)₅] or Si(PO₂Cl₂)₄ have been prepared, the composition of which depends on the solvents used. Some properties of these compounds are described and possible Constitutions are discussed.     

Ionic Dissociation of SiCl4: Formation of [SiL6]Cl4 with L=Dimethylphosphinic Acid

Reactions of SiCl₄ with R₂PO(OH) (R=Me, Cl) yield compounds with six-fold coordinated silicon atoms. Whereas R=Me afforded the hexacoordinated tetra-cationic silicon complex [Si(Me₂PO(OH))₆]⁴⁺ with chloride counter-ions, R=Cl caused release of HCl with formation of a cyclic dimeric silicon complex [Si(Cl₂PO(OH))(Cl₂PO₂)₃(μ-Cl₂PO₂)]₂ with bridging bidentate dichlorophosphates.     

Dichlorosilylene and dichlorogermylene transfer to alkylidenephosphanes

The detection of Me₃GeSiCl₃, a product from the Si₂Cl₆ cleavage of trimethylgermylphosphanes, as a useful new source of SiCl₂ moieties, as well as new trapping reactions of SiCl₂ and GeCl₂ with functional alkylidenephosphanes (Me₃Si)₂CPX (X = halide or dialkylphosphanyl [PRR^′; R = i-propyl, R^′ = t-butyl]) are reviewed. In the primary step of the reactions, insertion into the P-X bond is competing with addition to the PC bond. SiCl₂ and GeCl₂ insertions are followed by dimerisation reactions leading to new highly functional P-phosphanylalkylidenephosphanes, that may rearrange to diphosphenes like (XCl₂Si)(Me₃Si)₂C-PP-C(SiMe₃)₂SiCl₂X (X = F, Cl, P-i-Pr₂) or (Cl₃Ge)(Me₃Si)₂C-PP-C(SiMe₃)₂GeCl₂PRR^′ or/and react further with SiCl₂ or GeCl₂. Reaction of (Me₃Si)₂CP-PRR^′ (R = i-propyl, R^′ = t-butyl) with Me₃GeSiCl₃ leads in a very selective fashion to a complete PC double bond cleavage by unique double SiCl₂ addition with formation of a stable P-phosphanylphosphadisiletane.     

Darstellung und Eigenschaften einiger Hochchlorierter Oligosilane

Preparation and Properties of Some Highly Chlorinated Oligosilanes Tetrakis(trichlorosilyl)silane (neo-Si₅Cl₁₂) is cleaved by HCl in SiCl₄ solution to tris(trichlorosilyl)silane, HSi(SiCl₃)₃, and SiCl₄. HSi(SiCl₃)₃ and bis(trichlorosilyl)silane, H₂Si(SiCl₃)₂, can also be prepared in good yield by reaction of the methoxy compounds HSi[Si(OCH₃)₃]₃ and H₂Si[Si(OCH₃)₃]₂ with BCl₃. The mass, ¹H-n.m.r., and vibrational spectra of HSi(SiCl₃)₃ and H₂Si(SiCl₃) as well as some ¹H-n.m.r. data of HClSi(SiCl₃)₂, HCl₂SiSiCl₃ and H₂ClSiSiCl₃ are reported and discussed. An improved synthesis for neo-Si₅Cl₁₂ is given.     

Studies on organophosphorus compounds XLVIII Synthesis of Dithioesters from P,S-Containing Reagents and Carboxylic Acids and Their Derivatives

2,4-Bismethylthio-1,3,2,4-dithiadiphosphetane 2,4- disulfide, IIa, is prepared from 0,0-dimethyldithiophosphoric acid, Ia, and P₄S₁₀ at 160°C. 2,4-Bis(4-phenoxyphenyl)-1,3,2,4- dithiadiphsophetane 2,4-disulfide, IIc, and 2,4-bis(4-phenylthiolophenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, IId, are prepared at l60°C from P₄ S₁₀ and diphenylether and diphenylsulfides, respectively. Carboxylic acids RCOOH(R = CH₃ C₂H₅, n-C₃H₇, n-C₄H₉, C₆H₅CH₂, C₆H₈) react with compound Ia at 130°C to give the corresponding methyl dithioesters. Carboxylic acids RCOOH (R = C₆H₈-CH₂, C₆H₈) react with compound Ib at 200°C for 15 min to give the corresponding ethyl dithioesters, while low boiling acids (R = CH₃, C₂H₈, n-C₃H₇) yielded mixtures of the corresponding ethyl dithioester and ethyl carboxylate. Carboxylic acid chlorides RCOCl (R = ClCH₂, C₂H₅, t-C₄H₅ C₆H₅CH₂, C₆H₅, P-NO₂C₆H₄) react with compound IIa at 80°C to give the corresponding methyl dithioesters in good yields. S-Substituted thioesters react with IIC at 85°C to give the corresponding dithioesters in good yields. Dihydro2(3H)-furanone, VI, and 5-methyl-2(3H)-furanone, VII, react with IIa at 80°C; to dihydro-2(3H)-thiophenethione, VIII and 2,2'-dithiobis(5-methyl thiophene),IX, respectively. Also XI reacts with IIa,IIc, and IId to give VIII in nearly quantitative yields.     

Bildung siliciumorganischer Verbindungen. LXII. Teilbromierte Carbosilane

Formation of Organosilicon Compounds. LXII. Partial Brominated Carbosilanes The photobromination of 1 leads to compound 2 as well as to C-chlorinated derivatives if the time of reaction is prolonged. Compound 2 is also formed from (Br₂Si–CH₂)₃; Gl. (1) see ?Inhaltsübersicht”?. In a corresponding reaction (Cl₃Si–CH₂)₂SiCl₂ gives successively Cl₃Si–CHBr–SiCl₂–CH₂–SiCl₃, Cl₃Si–CBr₂–SiCl₂–CH₂–SiCl₃ and Cl₃Si–CCl₂–SiCl₂–CH₂–SiCl₃. (Cl₃Si)₂CBr₂ is accessible through the photobromination of (Cl₃Si)₂CH₂. The reactivity of the CBr₂-group is quite obvious in the reaction of Cl₂Si–CBr₂–SiCl₂–CH₂–SiCl₃ with LiAlH₄ yielding (H₃Si–CH₂)₂SiCl₂ as well as in the reaction of compound 2 with CH₃MgCl yielding [(CH₃)₂Si–CH₂]₃. By treatment of the SiH groups with bromine the preparation of compounds with the general formulas CH₃SiH_nBr_3?n; (H_3?nSiBr_n)₂CH₂; (H_3?nSiBr_n? CH₂)₂SiH_2?nBr_n; (H_2?nBr_nSi? CH₂)₃ and (H_3?nSiBr_n)₂CCl₂ is possible. Analysis of the nmr spectra shows that 1,3-Dibromo-1,3,5-trisilacyclohexane is formed to 67% in the trans and to 33% in the cis configuration; 1,3,5-Tribromo-1,3,5-trisilacyclohexane is formed to 80–90% in teh cis-trans configuration. The results of ¹H and ²⁹Si NMR investigations are reported.     

New Cyclic and Polycyclic Ring Systems Containing Group 14 (Si,Ge, Sn) and 16 (S,Se, Te) Elements

The reactions of Me₂MCl₂ (M = Si, Ge, Sn), Si₂Me₄Cl₂, Si₂Me₂Cl₃, Si₂Me₂Cl₄ and CH₂(SiCl₂Me)₂, and suitable mixtures thereof, with H₂S / NEt₃ and Li₂E (E = Se, Te) have been investigated and lead to a variety of new group 14 chalcogenide systems.     

Reaction of 1-germatranol hydrate with carboxylic acids

Reaction of 1-germatranol hydrate with carboxylic acids RCOOH (R = ClCH₂, PhCH=CH, Ph, 2-FC₆H₄, 3-BrC₆H₄, 3-HOC₆H₄, 3-EtOC₆H₄) in protic (CH₃OH, iso-C₅H₁₁OH) and aprotic polar solvent (CH₃CN) is studied. 1-Acyloxygermatranes RC(O)OGe(OCH{in2}CH{in2}){in3}N are formed in yields from 11 to ~100 % depending on the nature of the acid, solvent, duration of the process and the method of its completion. The reaction is the most effective in acetonitrile. Its topochemical completion (heating of the reaction residue in a vacuum) increases the yield of 1-acyloxygermatranes.     

Solid-state chlorodecarboxylation of mono- and dicarboxylic acids with the Pb(OAc)<Subscript>4</Subscript>-MCl system

Solid state reactions of acids RCOOH (R = n-C₇H₁₅, BuC(Et)H, n-C₉H₁₉, PhCH₂, PhCH₂CH₂, H₂C=CH(CH₂)₈, or MeOOC(CH₂)₃) with Pb(OAc)₄ combined with KCl, NaCl, CdCl₂, or NH₄Cl in the absence of a solvent and without mechanical activation afford chlorohydrocarbons RCl. The corresponding reactions of acids HOOC(CH₂)_nCOOH (n = 3–6) give dichloroalkanes Cl(CH₂)_nCl and γ-butyrolactone (n = 3).__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2105–2109, October, 2004.     

The Weakly Coordinating Tris(trichlorosilyl)silyl Anion

Closely following the procedure for the preparation of the base‐stabilized dichlorosilylene complex NHC^Dipp⋅SiCl₂ reported by Roesky, Stalke, and co‐workers (Angew. Chem. Int. Ed . 2009 , 48 , 5683–5686), a few crystals of the salt [NHC^Dipp−H⋅⋅⋅Cl⋅⋅⋅H−NHC^Dipp]Si(SiCl₃)₃ were isolated, aside from the reported byproduct [NHC^Dipp−H⁺⋅⋅⋅Cl⁻], and characterized by X‐ray crystallography (NHC^Dipp=N,N‐di(2,6‐diisopropylphenyl)imidazo‐2‐ylidene). They contain the weakly coordinating anion Si(SiCl₃)₃⁻, which was also obtained in high yields upon deprotonation of the conjugate Brønsted acid HSi(SiCl₃)₃ with NHC^Dipp or PMP (PMP=1,2,2,6,6‐pentamethylpiperidine). The acidity of HSi(SiCl₃)₃ was estimated by DFT calculations to be substantially higher than those of other H‐silanes. Further DFT studies on the electronic structure of Si(SiCl₃)₃⁻, including the electrostatic potential and the electron localizability, confirmed its low basicity and nucleophilicity compared with other silyl anions.     

Umsetzung von gemischten Siliciumhalogeniden und von Halogendisilanen mit Pyridin und 1,10-Phenanthrolin

Zusammenfassung Die Reaktion gemischter Siliciumhalogenide mit Pyridin (=py) oder 1,10-Phenanthrolin (=phen) führte zu den Additionsverbindungen SiClBr₃(py)₂, SiClBr₃(phen), SiCl₃Br(py)₂, SiCl₃Br(phen), SiCl₂J₂(py)₄, SiCl₂J₂(phen), SiCl₃J(py)₃ und SiCl₃J(phen). Eine Dismutation der gemischten Siliciumhalogenide wurde dabei nicht beobachtet. Ihre Darstellung erfolgte durch Umsetzung von ClSi(Net ₂)₃, Cl₂Si(Net ₂)₂ und Cl₃Si(Net ₂) (et=C₂H₅) mit HBr oder HJ. Si₂Cl₆ reagierte mit 3py zu SiCl₄(py)₂ und 1/n [SiCl₂(py)] _n , Si₂Br₆ analog zu SiBr₄(py)₂ und 1/n [SiBr₂(py)] _n , Si₃Cl₈ mit 4py zu SiCl₄(py)₂ und 2/n [SiCl₂(py)] _n .

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The reactions of mixed silicon halogenides with pyridine (=py), or 1.10-phenanthroline (=phen) resulted in the addition compounds SiClBr₃(py)₂, SiClBr₃(phen), SiCl₃Br(py)₂, SiCl₃Br(phen), SiCl₂I₂(py)₄, SiCl₂I₂(phen), SiCl₃I(py)₃ and SiCl₃I(phen). Dismutation of the mixed silicon halogenides in these reactions was not observed. Their preparation was achieved by cleaving of Si–N-bonds in ClSi(Net ₂)₃, Cl₂Si(Net ₂)₂ and Cl₃Si(Net ₂) (et=C₂H₅) with HBr or HI. Si₂Cl₆ reacted with 3py forming SiCl₄(py)₂ and 1/n [SiCl₂(py)] _n . The analogous reaction of Si₂Br₆ resulted in SiBr₄(py)₂ and 1/n [SiBr₂(py)] _n . Si₃Cl₈ and 4py formed SiCl₄(py)₂ and 2/n [SiCl₂(py)] _n .

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Mit 1 Abbildung

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66. Mitt.:U. Wannagat, K. Hensen, P. Petesch undF. Vielberg, Mh. Chem.98, 1415 (1967).

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Zugleich 7. Mitt. über Verbindungen von Nichtmetallhalogeniden mit Pyridin und seinen Homologen; 6. Mitt.:U. Wannagat, K. Hensen undP. Petesch, Mh. Chem.98, 1423 (1967).

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Mit Auszügen aus den DissertationenF. Vielberg, Techn. Hochsch. Aachen 1956, undK. Hensen, T. H. Aachen 1962.     

Fragmentation behavior of Si2Cln+ cations (n = 1—6)

Sector-field mass spectrometry was used to probe the fragmentation patterns of the cationic silicon chlorides Si₂Cl_n ⁺ (n = 1—6). For almost all Si₂Cl_n ⁺ ions, Si—Si fragmentation predominates the Si—Cl bond cleavage both in the metastable ion and collisional activation mass spectra. Analysis of the fragmentation patterns indicates that the long-lived radical cation Si₂Cl₆ ^·+ corresponds to a complex [SiCl₂·SiCl₄]^·+ rather than the intact molecular ion of hexachlorodisilane. The behavior of Si₂Cl₅ ⁺ is consistent with the formation of the (trichlorosilyl)dichlorosilyl cation Cl₃SiSICl₂ ⁺. Structural aspects are also discussed for the other Si₂Cl_n ⁺ species. A semi-quantitative analysis of the fragmentation patterns in conjunction with the literature thermochemistry data was used to estimate some thermochemical properties of the Si₂Cl_n ⁺ cations.     

A Disilene Base Adduct with a Dative Si–Si Single Bond

An experimental and theoretical study of the base‐stabilized disilene 1 is reported, which forms at low temperatures in the disproportionation reaction of Si₂Cl₆ or neo‐Si₅Cl₁₂ with equimolar amounts of NMe₂Et. Single‐crystal X‐ray diffraction and quantum‐chemical bonding analysis disclose an unprecedented structure in silicon chemistry featuring a dative Si→Si single bond between two silylene moieties, Me₂EtN→SiCl₂→Si(SiCl₃)₂. The central ambiphilic SiCl₂ group is linked by dative bonds to the amine donor and the bis(trichlorosilyl)silylene acceptor, which leads to push–pull stabilization. Based on experimental and theoretical examinations a formation mechanism is presented that involves an autocatalytic reaction of the intermediately formed anion Si(SiCl₃)₃^? with neo‐Si₅Cl₁₂ to yield 1 .