The hydrosilylation of propylene

The reactions of separate and competitive hydrosilylation of propylene with HSiCl₃, MeSiHCl₂, Me₂SiHCl, and MePh₂SiH in the presence of the Speier catalyst (SC) with different additives and a catalyst obtained from SC and propylene were studied. A mutual influence of the hydrosilanes in the competitive reactions was found. The influence of various additives to SC on the process was considered. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2048–2051, October, 1998.     

Ionische Strukturen von 4- bzw. 5fach koordiniertem Silicium Neue ionische Festkörperstrukturen von 4- bzw. 5fach koordiniertem Silicium: [Me3Si(NMI)]+Cl−, [Me2HSi(NMI)2]+Cl−, [Me2Si(NMI)3]2+ 2 Cl−· NMI

Ionic Structures of 4- and 5-coordinated Silicon. Novel Ionic Crystal Structures of 4- and 5-coordinated Silicon: [Me₃Si(NMI)]⁺ Cl^?, [Me₂HSi(NMI)₂]⁺ Cl^?, [Me₂Si(NMI)₃]²⁺ 2 Cl^?. NMI Me₃SiCl forms with N-Methylimidazole (NMI) a crystalline 1:1-compound which is stable at room temperature. The X-ray single crystal investigation proves the ionic structure [Me₃Si(NMI)]⁺Cl^? 1 which is the result of the cleavage of the Si? Cl bond and the addition of an NMI-ring. The reaction of Me₂HSiCl with NMI (in the molar ratio of 1:2), under cleavage of the Si? Cl bond and co-ordination of two NMI rings, yields the compound [Me₂HSi(NMI)₂]⁺Cl^? 2 . The analogous reaction of Me₂SiCl₂ with NMI (molar ratio 2:1) leads to a compound which consists of Me₂SiCl₂ and NMI in the molar ratio of 1:2. During the sublimation single crystals of the compound [Me₂Si(NMI)₃]²⁺ 2 Cl^?. NMI 3 are formed.     

Mechanism of the formation of complexes of trimethylchlorosilane with some nitrogen donors in nitrobenzene

Reactions of trimethylchlorosilane (Me ₃SiCl) with some nitrogen donors viz. pyridine, 2-, 3- and 4-picolines, quinoline and isoquinoline in nitrobenzene have been studied conductometrically. The conductivities of the solutions during these reactions have been interpreted in terms of the formation of (Me ₃Si.D)⁺, (Me ₃SiCl₂)^? andMe ₃SiCl.D (D=N-donor molecule) species.     

Etude de la metallation de l'oxyde de diferrocenyl phenyl phosphine

The reaction of n-BuLi with phenyldiferrocenylphosphine oxide yields a mixture of two isomeric dianions. This mixture reacts with Me₃SiCl, Br₂, CO₂, PhCHO and PhCHNPh to give bifunctional products. With CoCl₂, Me₂SiCl₂, Ph₂SiCl₂, Bu₂SnCl₂ and PhCOOEt, the same mixture gives cyclic products. In almost every case each of these compounds is a mixture of two isomers corresponding to the original compound. The characteristic patterns of the PMR spectra are in full agreement with the structures proposed for the isomeric dianions.     

Synthese der Silatetraphospholane (tBuP)4SiMe2, (tBuP)4SiCl2 und (tBuP)4Si(Cl)SiCl3 Molekül- und Kristallstruktur von (tBuP)4SiCl2

Synthesis of the Silatetraphospholanes (tBuP)₄SiMe₂, (tBuP)₄SiCl₂, and (tBuP)₄Si(Cl)SiCl₃ Molecular and Crystal Structure of (tBuP)₄SiCl₂ The reaction of the diphosphide K₂[(tBuP)₄] 7 with the halogenosilanes Me₂SiCl₂, SiCl₄ or Si₂Cl₆ in a molar ratio of 1:1 leads via a [4 + 1]-cyclocondensation reaction to the silatetraphospholanes (tBuP)₄SiMe₂ 1,1-dimethyl-1-sila-2,3,4,5-tetra-t-butyl-2,3,4,5-tetraphospholane, 1 , (tBuP)₄SiCl₂, 1,1-dichloro-1-sila-2,3,4,5-tetra-t-butyl-2,3,4,5-tetraphospholane, 2 , and (tBuP)₄Si(Cl)SiCl₃, 1-chloro-1-trichlorsilyl-1-sila-2,3,4,5-tetra-t-butyl-2,3,4,5-tetraphospholane, 3 , respectively, with the 5-membered P₄Si ring system. The reaction leading to 1 is accompanied with the formation of the by-product Me₂(Cl)-Si–(tBuP)₄–Si(Cl)Me₂ 1a (5:1), which has a chain structure. On warming to 100°C 1a decomposes to 1 and Me₂SiCl₂. The compounds 2 and 3 do not react further with an excess of 7 due to strong steric shielding of the ring Si atoms by the t-butyl groups. 1, 2 and 3 could be obtained in a pure form and characterized NMR spectroscopically; 2 was also characterized by a single crystal structure analysis. 1a was identified by NMR spectroscopy only.     

Bestimmung von Methylchlorsilanen in Chlorsilanen mit Hilfe eines Systems Gas-Chromatograph und Massenspektrometer

Zusammenfassung Die Verbindungen (CH₃)₂SiHCl, CH₃SiHCl₂ und (CH₃)₃SiCl wurden in SiHCl₃/SiCl₄-Gemischen gas-chromatographisch analysiert, wobei ein Massenspektrometer mit fester Masseneinstellung als Detektor eingesetzt wurde. Die Nachweisgrenze liegt bei ca. 1 Gew.-ppm für diese Verbindungen.

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Determination of methylchlorosilanes in chlorsilanes with a gas-chromatograph/ mass spectrometer system

Summary The compounds (CH₃)₂SiHCl, CH₃SiHCl₂ and (CH₃)₃SiCl were analyzed in SiHCl₃/SiCl₄ mixtures by gas chromatography using a mass spectrometer being focused on definite peaks as detector. The detection limit was found to be about 1 ppm (wt) of these compounds.

     

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.     

Zur Bildung cyclischer Silylphosphane Umsetzung von Li-Phosphiden mit R2SiCl2 (R = Me,Et, t-Bu)

Formation of Cyclic Silylphosphanes. Reaction of Li-Phosphides with R₂SiCl₂ (R? Me, Et, t-Bu) The reaction of Me₂SiCl₂ with Li-phosphides (mixture of LiPH₂, Li₂PH) leads to the formation of Me₂Si(PH₂)Cl 1 , Me₂Si(PH₂)₂ 2 , H₂P? SiMe₂? PH? SiMe₂Cl 3 , (H₂P? SiMe₂)₂PH 4 , (HP? SiMe₂)₃ 6 , 5 , 7 , 8 , 9 , 10 , 40 . Excess of phosphides in Et₂O – as well as excess of LiPH₂ – favourably forms 10 . Li₂PH (virtually free of Li₃P and LiPH₂) is obtained by reaction of LiPH₂ · DME with LiBu; Li₃P by reaction of PH₃ with LiBu in toluene. Isomerization by Li/H migration determines the course of reaction of the PH-bearing compounds with Li-phosphides. With Me₂SiCl₂ Li₃P mainly generates compound 10 . The reaction of the Li-phosphides with Et₂SiCl₂ mainly leads to (HP? SiEt₂)₃ 18 and (HP? SiEt₂)₂ 17 as well as to Et₂Si(PH₂)Cl 11 , Et₂Si(PH₂)₂ 12 , (ClEt₂Si)₂PH 13 , H₂P? SiEt₂? PH? SiEt₂Cl 14 , (H₂P? SiEt₂)₂PH 15 and 16 . In the reaction with LiPH₂ · DME the same compounds are obtained and isomerization by Li/H migration (formation of PH₃) already begins at ?70°C. In toluene ClEt₂Si? P(SiEt₂)₂P? SiEt₂Cl is additionally formed. Derivatives of 9, 10, 40 are not observed. The reaction of (t-Bu)₂SiCl₂ with LiPH₂ leads to HP[Si(t-Bu)₂]₂PH 20 (yield 76%) and formation of PH₃, the reaction with Li₂PH to 20 (54%) besides HP[Si(t-Bu)₂]₂PLi 21 .     

Some chemical transformations of 5-(propyn-2-yl)bicyclo[2.2.1]-2-heptene

Conclusions The Grignard reagent, obtained from 5-(propyn-2-yl)bicyclo[2.2.1]-2-heptene, reacts easily with Ac₂O, Et₂SiCl₂, Me₃SiCl, and acrolein to give in high yields [2.2.1]bicyclo-2-heptene derivativesthat contain in the side chain either an acetyl, diethylsilyl, trimethylsilyl, or a hydroxypropen-1-yl group. The Mannich reaction was also run with 5-(propyn-2-yl)bicyclo[2.2.1]-2-heptene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2586–2589, November, 1982.     

Silicon Carbide Nanostructures from Reactions between Vapors of Organochlorosilanes and Liquid of Sodium‐Factors Affecting Morphology and Composition

Cubic shells and spherical nanoparticles of β‐SiC were produced at 1273 K by processing the ceramic precursors formed from the reactions between vapors of organochlorosilanes, Me₂SiCl₂, MeSiCl₃, MeSiHCl₂, and PhSiCl₃, and liquid Na at 523‐723 K. From Me₂SiCl₂, a flexible linear polycarbosilane precursor was synthesized and covered the NaCl byproduct surface to form a cubic shape. Hollow cubic β‐SiC shells were produced after the NaCl templates were removed. From MeSiCl₃, a rigid cross‐linked polycarbosilane was produced and phase segregated from the NaCl byproduct. The precursor was transformed into nanoparticles without special morphology. MeSiHCl₂ produced a cross‐linked polysilane precursor at low temperatures, which can be converted into a mixture of β‐SiC and Si nanoparticles. At high temperatures, the polysilane converted to polycarbosilane and produced hollow cubic β‐SiC shells. The carbon‐rich PhSiCl₃ generated cube‐like particles as the final product, which contained β‐SiC and carbon.     

Synthesis and Reactions of P-Rich Silylphosphanes

Abstract

The formation of P-rich compounds like (Me₃Si)₃P₇ 1 and P₄(SiMe₂)₃ 2 generated from Na/K-alloy, white phosphorus, Me₃SiCl and Me₂SiCl₂, resp., or the formation of 1 from P₄, lithiumalkyles and Me₃SiCl on the other hand occurs in several reaction steps₁.     

Reaktion von Bis(trimethylsilylamino)dichlorsilan mit Titantetrachlorid ‐ Synthese und Kristallstruktur von [μ‐ClTiCl2N(SiMe3)SiCl2NH2]2

TiCl₄ reacts quantitatively with Cl₂Si(NHSiMe₃)₂ in n‐pentane under evolution of Me₃SiCl yielding [μ‐ClTiCl₂N(SiMe₃)‐SiCl₂NH₂]₂ ( 1 ), which is obtained as a yellow, crystalline solid forming small intergrown needles, that rapidly hydrolyse. The product 1 shows a thermal stability up to 80?C. The molecular structure of 1 has been solved by X‐ray powder diffraction methods and it could be confirmed by single‐crystal X‐ray structure determination at ‐70 ?C. Accordingly, in the solid 1 is a dimer ([μ‐ClTiCl₂N(SiMe₃)SiCl₂NH₂]₂, P2₁/n (no. 14), Z = 2, a = 1504.89(6), b = 1296.33(6), c = 710.90(4) pm, and β = 91.276(2)?).     

SiCl 3 + and SiCl+ affinities for pyridines determined by using the kinetic method with multiple stage mass spectrometry: Agostic effects in the gas phase

Cluster ions, Py₁SiCl ₃ ⁺ Py₂ and Py₁SiCl⁺Py₂, where Py₁ and Py₂ represent substituted pyridines, formed upon reactive collisions of mass-selected SiCl ₃ ⁺ or SiCl⁺ cations with a mixture of pyridines, are shown to have loosely bound structures by multiple stage mass spectrometry experiments in a pentaquadrupole mass spectrometer. The fragment ion abundance ratio, ln([Py₁SiCl _n ⁺ ]/[Py₂SiCl _n ⁺ ]) (n=1 or 3) is used to estimate the relative SiCl ₃ ⁺ or SiCl⁺ affinities of the constituent pyridines by the kinetic method. In the case of clusters comprised of meta- and/or para-substituted pyridines (unhindered pyridines), the SiCl ₃ ⁺ and SiCl⁺ affinities are shown to display excellent linear correlations with the proton affinities (PAs). On the assumption that the effective temperatures of the SiCl ₃ ⁺ - and SiCl⁺-bound dimers are 555 K (i. e., the same as those of the corresponding Cl⁺-bound dimers), SiCl ₃ ⁺ and SiCl⁺ affinities of the substituted pyridines, relative to pyridine, are estimated to be 3-MePy (2.1 kcal/mol), 4-MePy (3.2 kcal/mol), 3-EtPy (3.7 kcal/mol), 4-EtPy (4.2 kcal/mol), 3,5-diMePy (4.8 kcal/mol), and 3,4-diMePy (5.4 kcal/mol). The SiCl ₃ ⁺ and SiCl⁺ cation affinities are related to the proton affinities by the expressions: relative (SiCl ₃ ⁺ ) affinity = 0.95 ΔPA and relative (SiCl⁺) affinity = 0.60 ΔPA. The smaller constant in the relationship between the relative SiCl affinity and the relative proton affinity is the result of weaker bonding. Steric effects between the ortho-substituted alkyl group and the central SiCl ₃ ⁺ cation reduce the SiCl ₃ ⁺ affinities of dimers that contain ortho-substituted pyridines. The magnitude of the steric acceleration of fragmentation is used to measure a set of gas-phase steric parameters (S ^k). The steric effects in the SiCl ₃ ⁺ dimers are similar in magnitude to those in the corresponding Cl⁺-bound dimers but weaker than those produced by the bulky [OCNCO]⁺ group. An inverted steric effect is observed in those SiCl⁺-bound dimers that incorporate ortho-substituted pyridines and is ascribed to auxiliary Si-H-C bonding, which stabilizes the ortho-substituted pyridine-SiCl⁺ bond. This auxiliary bonding appears to correspond to agostic bonding, which is well characterized in solution and occurs in competition with steric effects that weaken the pyridine-SiCl⁺ interaction. Ion-molecule reactions of pyridines with halosilicon radical cations SiCl ₂ ⁺ and SiCl ₄ ⁺ as well as alkylated halosilicon cations Si(CH₃)₂Cl⁺ and Si(CH₃)Cl ₂ ⁺ also are investigated. In these cases, charge exchange and associated reactions are the main reaction channels, and clustering is not observed.     

Reaktionen des Gallium‐haltigen Heterocyclus [Me2Ga{HNC(Me)}2CCN]

Reactions of the Gallium‐containing Heterocycle [Me₂Ga{HNC(Me)}₂CCN] The reaction of [Me₂Ga{HNC(Me)}₂CCN] ( 1 ) with fac‐[Mo(CO)₃(MeCN)₃] leads after addition of TMEDA to the molybdenum complex fac‐[Mo(CO)₃( 1 )(TMEDA)] ( 2 ). Under identical reaction conditions with fac‐[W(CO)₃(MeCN)₃] only the tetracarbonyle complex [W(CO)₄(TMEDA)] ( 3 ) could be isolated. Treatment of dilithiated 1 with Me₂SiCl₂ or InCl₃ initiate a fragmentation of the skeleton in 1 . Obtained were the salt [Me₂Ga(TMEDA)][Me₂GaCl₂] ( 4 ) and the indium complex [Me₂InCl(TMEDA)] ( 5 ), respectively. 2 — 5 were investigated by spectroscopical and spectrometrical methods as well as by X‐ray structure determinations. According to these 1 occupies a facial site in 2 by donation of the N‐Atom from the NC group in 1 . The molecules 2 are forming a network of hydrogen bonds. In 3 , the TMEDA ligand acts as an intramolecular chelate ligand. In the salt 4 , the cation as well as the anion are coordinated in a distorted tetrahedral environment, while in 5 a distorded trigonal‐bipyramidal coordination‐sphere is present, leading to a elongated In1‐Cl1 distance of 261.74(9) pm.     

Activation of reducing agents. Sodium hydride containing complex reducing agents 24. Beneficial effect of Me3SiCl on the reducing properties of NiCRA

Reduction of carbon-carbon double bonds can be achieved with either NiCRA or NiCRASi (nickel containing Complex Reducing Agent activated by Me₃SiCl). Selective reduction of polyunsaturated hydrocarbons or unsaturated ketones are easily performed with both reagents.     

The stable silylene Si[(NCH2Bu)2C6H4-1,2]: Reactions with Group 14 element halides

Reaction of the thermally stable silylene Si[(NCH₂Bu^t)₂C₆H₄-1,2] (1) [abbrev. as Si(NN)] with SiX₄ (X = Cl or Br) afforded the disilanes (NN)SiX(SiX₃) and [(NN)SiX]₂ (X = Br only), the trisilane (NN)SiX-[(SiX₃)Si(NN)] and the monosilane (NN)SiX₂ (X = Br only), whereas treatment of 1 with MCl₄ (M = Ge or Sn) yielded (NN)SiCl₂ and MCl₂. [(NN)SiBr]₂ and (NN)SiBr₂ were also obtained by reaction of 1 with Br₂. Reaction of 1 with PhSiCl₃ yielded the disilane (NN)SiCl(SiCl₂Ph) and trisilane [(NN)SiCl]₂SiClPh, whereas the disilane (NN)SiCl(SiCl₂Me) was obtained with MeSiCl₃. The trisilane (NN)SiCl-[(SiCl₃)Si(NN)] was thermally labile and converted to [(NN)SiCl]₂SiCl₂.     

Alternativ-Liganden. XXII. Rhodium(I)-Komplexe mit Donor/Akzeptor-Liganden des Typs Me2PCH2CH2SiXnMe3−(X = F,Cl, OMe)

Alternative Ligands. XXII. Rhodium(I) complexes with Donor/Acceptor Ligands of the Typs Me₂PCH₂CH₂SiX_nMe_3?n(X = F, Cl, OMe) Donor/acceptor ligand of the type Me₂PCH₂SiX_nMe_3?n react with [Rh(CO)₂Cl]₂ ( 1 ) to give the mononuclear complexes RhCl(CO)(PMe₂CH₂CH₂SiX_nMe_3?n)₂ ( 2-6 , Table 1) with planar geometry of the donor atoms, one exception being Me₂PCH₂CH₂CH₂SiCl₃, yielding the crystalline Rh^III-complex RhCl₂(CO)(PMe₂CH₂CH₂SiCl₂)(PMe₂CH₂CH₂SiCl₃) ( 7 ) by oxidative addition of one of the SiCl bonds to the Rh¹ precursor. Structures with Rh → Si interaction between the basic central atoms and the acceptor group SiX_nMe_3?n could be detected in the isolated products neither spectroscopically nor by X-ray diffraction of the two representatives RhCl(CO)(PMe₂CH₂CH₂SiF₃)₂ ( 2 ) and RhCl(CO)[PMe₂CH₂CH₂siF₃]₂ ( 2 ) and RhCl(CO) [PMe₂CH₂CH₂Si(OMe₃]₂ ( 6 ). The presence of such acid/base adducts in the reaction mixture is indicated for the more acidic acceptor groups SiX_nMe_3?n byv_co values near 1990cm^?1, (see Table 3). The complex RhCl(CO)PMe₃)(PMe₂CH₂CH₂SiF₃ ( 8 ) is obtained by the reaction of RhCl(CO)(PMe₃)₂ ( 9 ) with Me₂PCH₂SiF₃ and has been identified spectroscopically in a mixture with 2 and 9 .     

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.     

Mechanism of the Reaction of Amines with 5‐[(Aryl‐ or Alkylamino)hydroxymethylene]‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐diones in the Presence of Chlorotrimethylsilane (Me3SiCl)

Addition of chlorotrimethylsilane (Me₃SiCl) to the mixture of a carbamoyl‐substituted Meldrum's acid, i.e., a 5‐[(arylamino)hydroxymethylene]‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione of type 1 and a secondary amine as nucleophile strongly accelerated the rate of their reaction. The reason for this phenomenon observed, during our previous research, remained, however, unclear. To elucidate the mechanism of this reaction, we assumed and verified three possible pathways for the action of Me₃SiCl (cf. Scheme 2): The acceleration of the reaction is caused i) by formation of a O‐trimethylsilylated Meldrum's acid of type 2 , ii) by the silylated amine 3 , or iii) by the presence of HCl liberated from Me₃SiCl. The performed experiments revealed that the faster course of reaction is caused by the formation of N‐trimethylsilylated amines of type 3 .