Reaktionen von R4Sb2 (R = Me,Et) mit (Me3SiCH2)3M (M = Ga,In) und Kristallstrukturen von [(Me3SiCH2)2InSbMe2]3 und [(Me3SiCH2)2GaOSbEt2]2

Reactions of R₄Sb₂ (R = Me, Et) with (Me₃SiCH₂)₃M (M = Ga, In) and Crystal Structures of [(Me₃SiCH₂)₂InSbMe₂]₃ and [(Me₃SiCH₂)₂GaOSbEt₂]₂ The reaction of (Me₃SiCH₂)₃In with Me₂SbSbMe₂ gives [(Me₃SiCH₂)₂InSbMe₂]₃ ( 1 ) and Me₃SiCH₂SbMe₂. [(Me₃SiCH₂)₂GaOSbEt₂]₂ ( 2 ) is formed by the reaction of (Me₃SiCH₂)₃Ga with Et₂SbSbEt₂ and oxygen. The syntheses and the crystal structures of 1 and 2 are reported.     

Darstellung und Kristallstruktur von [(Me3SiCH2)2InP(H)Ad]2

Preparation and Crystal Structure of [(Me₃SiCH₂)₂InP(H)Ad]₂ Reaction of (Me₃SiCH₂)₃ In with AdPH₂ (Ad = adamantyl) in the presence of AgNO₃ leads to [(Me₃SiCH₂)₂InP(H)Ad]₂ 1 in 30% yield. The crystal structure of 1 is discussed.     

Spektroskopische Untersuchungen zu Substituenteneffekten in Silylmethylsilanen

Spectroscopic Investigations on Substituent Effects in Silylmethylsilanes The silanes Me_3?n(Me₃SiCH₂)_nSiH (n = 1–3), (RMe₂SiCH₂)₃SiH (R = n-Bu, n-Pr, Et, PhCH₂, Ph) and Me₃ElCH₂SiMe₂H (El = Ge, Sn) were prepared. The frequencies of the Si? H stretching vibration, the ²⁹Si? ¹H coupling constants and the ²⁹Si n.m.r. chemical shifts were measured. The ?(SiH) and J(²⁹Si? ¹H) values in the silanes Me_3?n(Me₃SiCH₂)_nSiH depend on the number of trimethylsilymethyl groups. There is hardly an influence of the substituents R on these values in the silanes (RMe₂SiCH₂)₃SiH. The frequencies of the Si? H stretching vibrations in the silanes Me₃ElCH₂SiMe₂H (El = Si, Ge, Sn) show the order Si?Ge > Sn. The ₂₉Si n.m.r. chemical shifts of the Si(H) signals are approximately equal in the silanes Me_3?n(Me₃SiCH₂)_nSiH and (RMe₂SiCH₂)₃SiH.     

Reaktionen eines Dibismutans und von Cyclobismutanen mit Metallcarbonylen ‐ Synthesen von Komplexen mit R2Bi‐, RBi‐, Bi2‐ und Bin‐Liganden (R = Me3CCH2, Me3SiCH2)

Reactions of a Dibismuthane and of Cyclobismuthanes with Metal Carbonyls ‐ Syntheses of Complexes with R₂Bi‐, RBi‐, Bi₂‐ and Bi_n‐ligands (R = Me₃CCH₂, Me₃SiCH₂) Reactions of [Fe₂(CO)₉] with [(Me₃CCH₂)₄Bi]₂ or cyclo‐(Me₃SiCH₂Bi)_n (n = 3 ‐ 5) lead to the complexes [(R₂Bi)₂Fe(CO)₄], [RBiFe(CO)₄]₂[R = Me₃CCH₂, Me₃SiCH₂] and [Bi₂Fe₃(CO)₉]. [Bi₂{Mn(CO)₂C₅H₄CH₃}₃] forms in a photochemical reaction of [Mn(CO)₃C₅H₄CH₃] with cyclo‐(Me₃SiCH₂Bi)_n.     

Destruction reactions of some σ-derivatives of vanadium

The interactions of (Me₃SiCH₂)₄V and (Me₃SiCH₂)₃V·THF with cyclopentadiene have been studied. Me₄Si and Cp₂V were isolated. A scheme of the reactions was proposed which involves formation of unstable monocyclopentadienyl derivatives of vanadium. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1542–1544, August, 1997.     

Synthesis and characterization of [(Me3SiCH2)2GaP(SiMe3)2]2, an example of a gallium-phosphorus dimer obtainable only through an indirect reaction pathway

The dimeric gallium-phosphorus compound [(Me₃Si-CH₂)₂GaP(SiMe₃)₂]₂ ( 1 ) was prepared from the 1:1 mole ratio lithium-halide elimination reaction of (Me₃SiCH₂)₂GaP(SiMe₃)₂Ga(CH₂SiMe₃)₂Cl with LiP-(SiMe₃)₂ in benzene solution and has been characterized through multinuclear solution NMR, partial elemental analysis, and single-crystal X-ray analysis. Compound 1 could not be obtained from the direct reactions of (Me₃SiCH₂)₂GaCl with P(SiMe₃)₃ or LiP(SiMe₃)₂. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:147–150, 1998     

Synthesis and Structures of ansa‐Titanocene Complexes with Diatomic Bridging Units for Overall Water Splitting

The synthesis of a series of ansa‐titanocene dichlorides [Cp′₂TiCl₂] (Cp′=bridged η⁵‐tetramethylcyclopentadienyl) and the corresponding titanocene bis(trimethylsilyl)acetylene complexes [Cp′₂Ti(η²‐Me₃SiC₂SiMe₃)] is described. The ethanediyl‐bridged complexes [C₂H₄(C₅Me₄)₂TiCl₂] ( 2 ‐Cl₂) and [C₂H₄(C₅Me₄)₂Ti(η²‐Me₃SiC₂SiMe₃)] ( 2‐ btmsa; btmsa=η²‐Me₃SiC₂SiMe₃) can be obtained from the hitherto unknown calcocenophane complex [C₂H₄(C₅Me₄)₂Ca(THF)₂] ( 1 ). Furthermore, a heterodiatomic bridging unit containing both, a dimethylsilyl and a methylene group was introduced to yield the ansa‐titanocene dichloride [Me₂SiCH₂(C₅Me₄)₂TiCl₂] ( 3 ‐Cl₂) and the bis(trimethylsilyl)acetylene complex [Me₂SiCH₂(C₅Me₄)₂Ti(η²‐Me₃SiC₂SiMe₃)] ( 3 ‐btmsa). Besides, tetramethyldisilyl‐ and dimethylsilyl‐bridged metallocene complexes (structural motif 4 and 5 , respectively) were prepared. All ansa‐titanocene alkyne complexes were reacted with stoichiometric amounts of water; the hydrolysis products were isolated as model complexes for the investigation of the elemental steps of overall water splitting. Compounds 1 , 2 ‐btmsa, 2 ‐(OH)₂, 3 ‐Cl₂, 3 ‐btmsa, 4 ‐(OH)₂, 3 ‐alkenyl and 5 ‐alkenyl were characterised by X‐ray diffraction analysis.     

Preparation and reactivity of the new cyclopentadienyl-bridged complex (Me2SiCH2CH2SiMe2)(C5H4Fe(CO)2)2

A new metal-metal bonded binuclear iron system [Me₂SiCH₂CH₂SiMe₂][η⁵-C₅H₄Fe(CO)₂]₂ (2) has been prepared by treating two equivalents of NaCp with one equivalent of ClSi(Me)₂CH₂CH₂SiClMe₂ obtaining the intermediate (C₅H₅)Si(Me)₂CH₂CH₂Si(Me)₂(C₅H₅) which then is directly allowed to react with Fe(CO)₅ given 2 in 30% yield. From this cyclopentadienyldisilyl linked system three new binuclear irom complexes are formed. Treatment of 2 with Na/Hg in THF produced the dianion [Me₂SiCH₂CH₂SiMe₂][η⁵-C₅H₄Fe(CO)₂^?]₂ which is quenched with CH₃I giving [Me₂SiCH₂CH₂SiMe₂][η⁵-C₄H₄Fe(CO)₂CH₃]₂ (4) in 76% yield. Complex 2 is oxidized with 1.2 equivalent of I₂ to give [Me₂SiCH₂CH₂SiMe₂][η⁵-C₅H₄Fe(CO)₂I]₂ (5) in 85% yield. Photolysis of 5 (1 equiv.) and PPh₃ (3 equiv.) results in the formation of the bis-substituted compound [Me₂SiCH₂CH₂SiMe₂][η⁵-C₅H₄Fe(CO)(PPh₃)I]₂ (6). These four new binuclear iron complexes are characterized by ¹H, ¹³C, and ³¹P NMR and IR spectroscopy.     

Stereo- and regioselective routes to allylic silanes

The Ni- or Pd-catalyzed reaction of alkenyl iodides with Me₃SiCH₂Mgcl provides various types of allytrimethylsilanes in excellent yields in a highly stereo- and regioselective manner, while the Zr-catalyzed carboalumination of Me₃SiCH₂CCH followed by replacement of Al with carbon groups by known reactions produces allylsilanes represented by $\text{2}$.     

Synthesis and properties of alkylvanadium(III) alkoxides

The reactions of R₃V · THF (R  C₆F₅, CH₂SiMe₃) with one t-BuOH equivalent result in formation of unstable R₂V(Ot-Bu)·THF, which disproportionates readily to V^IV and V^II compounds. The interaction of V(Ot-Bu)₃ with Me₃SiCH₂Li in diethyl ether is accompanied by formation of the at-complex [Me₃SiCH₂V(Ot-Bu)₃]^-Li⁺ which decomposes with formation of (Me₃SiCH₂)₂V(Ot-Bu)₂ and [V(Ot-Bu)₃]^-Li⁺. As a result of exchange reaction of V(Ot-Bu)₃ with one mole of RMgX, the complexes RV(Ot-Bu)₂·XMgOt-Bu (R  Me, X  Br, R  CH₂Ph, CH₂SiMe₃, C₆F₅, X  Cl) have been obtained. The insertion of carbon dioxide in vanadiumcarbon and vanadiumoxygen bonds has also been investigated.     

[μ‐(Me3SiCH2Sb)5–Sb1,Sb3–{W(CO)5}2] und [{(Me3Si)2CHSb}3Fe(CO)4] – zwei cyclische Komplexe mit Antimon‐Liganden

Syntheses and Crystal Structures of [μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] and [{(Me₃Si)₂CHSb}₃Fe(CO)₄] – Two Cyclic Complexes with Antimony Ligands cyclo‐(Me₃SiCH₂Sb)₅ reacts with [(THF)W(CO)₅] (THF = tetrahydrofuran) to form cyclo‐[μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] ( 1 ). The heterocycle cyclo‐ [{(Me₃Si)₂CHSb}₃Fe(CO)₄] ( 2 ) is formed by an insertion reaction of cyclo‐[(Me₃Si)₂CHSb]₃ and [Fe₂(CO)₉]. The crystal structures of 1 and 2 are reported.     

Complexes of Cyclostibane-Ligands

The reaction of cyclo-(Me₃SiCH₂Sb)₅ with excess of W(CO)₅thf (thf = tetrahydrofuran), in thf gives the 1:2 complex: cyclo-(Me₃SiCH₂Sb)₅ 1,3-[W(CO)₅]₂. A X-ray crystal structure analysis reveals that the complex contains a five membered antimony ring in the envelope conformation. The W(CO)₅ fragments are in trans positions.     

Synthesis and study of the thermal stability of siliconcontaining esters of phosphorus acids. 4. Thermal rearrangement of trimethylsilylmethyl esters of phosphorus acids

NMR spectroscopy has been used to study the thermal rearrangement of siliconeopentyl esters of phosphorus acids Me₃SiCH₂OP(O)R₂ (I, R=CF₃CH₂O, PhO, t-BuCH₂O, Bu). It has been established that in all cases the products of the rearrangement are the respective silyl esters Me₂EtSiOP(O)R₂ (II). The thermal rearrangement of (Me₃SiCH₂O)₂P(O)OR (III, R'=Ph, t-BuCH₂, Me₃SiCH₂) is similar. It has been shown that electronic and steric attributes of the substituents R and R on the phosphorus atom are practically without effect on the extent of the thermal rearrangement. The presence of acidic additives, and initiators and inhibitors of radical reactions did not significantly influence the course of the rearrangement. It was concluded that this rearrangement apparently takes place as a result of heterolysis of the C-OP bond and simultaneous nucleophilic attack on the silicon atom by the phosphoryl part of the molecule.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1155–1158, May, 1991.     

Reactions of pentafluorophenyltrimethylsilane and cyanomethyltrimethylsilane with carbonyl compounds catalyzed by cyanide anions

Treatment of pentafluorophenyltrimethylsilane (I) and cyanomethyltrimethylsilane (II) with enolizable ketones in the presence of a catalytic amount of potassium cyanide-18-crown-6 complex gave the corresponding trimethylsilyl enol ethers. The same dehydrogenative silylation of acetylacetone and benzoylacetone with silane I was extended to the preparation of 2,4-bis(trimethylsiloxy)-1,3-pentadiene and 1-phenyl-1,3 -bis(trimethylsiloxy)-1,3-butadiene, respectively. The dehydrogenative silylation of acetylacetone and benzoylacetone with dimethylbis(pentafluorophenyl)silane under the same conditions affords novel heterocyles 5-methylene-2,6-dioxa-1-silacylohex-3-enes. In the reaction studied the silylating ability of the silanes increases in the order Me₃SiCN ? Me₂Si(CN)₂ < Me₃SiCH₂CN < Me₃SiC₆F₅ ? Me₂Si(C₆F₅)₂. On the other hand, potassium cyanide-18-crown-6 complex catalyzed the addition of silane I or II to a carbonyl group of non-enolizable compounds such as benzaldehyde, crotonaldehyde, and methyl(triethylgermyl)ketene.     

Schwefeldioxid als Ligand und Synthon. II. Synthese und Reaktionen der Trimethylsilyl-methansulfinsäure und ihrer Derivate

Sulfur Dioxide as Ligand and Synthon. II. Synthesis and Reaction of Trimethylsilyl Methane Sulfinic Acid and its Derivatives Synthesis and reaction of trimethylsilyl methane sulfinic acid and its derivatives, of the type Me₃SiCH₂S(O)? Y (Y = OH, OM, OR, NR₂) synthesized by insertion of SO₂ and R¹NSO, respectively, into Me₃SiCH₂MgCl are described. The compounds obtained are characterized by means of i.r., ¹H, ²⁹Si, and ¹³C n.m.r. spectroscopy.     

Silylmethyl and related complexes II. Preparation,spectra, and thermolysis of the tetraneopentyls of titanium,zirconium, and hafnium

The preparation and characterisation of the Group IVA neopentyls (Me₃CCH₂)₄M (M = Ti, Zr, or Hf) is described. Spectroscopic data (IR, Raman, mass, ¹H NMR, and PE) are provided; IR and Raman bands have been assigned by comparison with results on Group IVB analogues (M = Ge or Sn). MC₄ stretching vibrations fall in the range 540–485 cm^?1, and bending modes at 240–283 cm^?1. Thermal decomposition gives neopentane as the sole detectable product; qualitatively, stability increases in the order M = Ti < Zr < Hf and for R₄M : R = Me ? Me₃CCH₂ ≈ Me₃SiCH₂. (Me₃CCH₂)₄Ti is aerobically oxidised in benzene to give (Me₃CCH₂O)₄Ti     

Die Hydroaluminierung von 1,1,4,4‐Tetramethyl‐2,3‐diazabutadien mit Dialkylaluminiumhydriden – Synthese von Dialkylaluminiumhydrazoniden

The Hydroalumination of 1,1,4,4‐Tetramethyl‐2,3‐diazabutadiene by Dialkylaluminium Hydrides – Synthesis of Dialkylaluminium Hydrazonides 1,1,4,4‐Tetramethyl‐2,3‐diazabutadiene reacted with dimethylaluminium hydride by hydroalumination of only one C=N double bond. The hydrazone derivative [Me₂Al–N(CHMe₂)–N=CMe₂]₂ ( 1 ) was formed which gave a dimer possessing a six‐membered Al₂N₄ heterocycle. The hydroalumination of both C=N double bonds was not observed. Also an excess of di(tert‐butyl)‐ or bis(trimethylsilylmethyl)aluminium hydride afforded only the product of a single hydroalumination step, a second dialkylaluminium hydride molecule was attached via a coordinative interaction between its central aluminium atom and the nitrogen atom of the C=N double bond and in addition via a 3 c‐2 e Al–H–Al bond. Compounds [(Me₃C)₂Al][(Me₃C)₂AlH]N(CHMe₂)NCMe₂ ( 2 ) and [(Me₃SiCH₂)₂Al][(Me₃SiCH₂)₂AlH]N(CHMe₂)NCMe₂ ( 3 ) were formed which have five‐membered Al₂N₂H heterocycles. Thermolysis of 2 gave by C–H activation compound [(Me₃C)₂Al]₂[CH₂C(Me)=N–]₂ ( 4 ) in trace amounts which possesses two anellated AlN₂C₂ rings with a common N–N bond. In contrast, the thermal decomposition of 3 yielded by the cleavage of the N–N bond a dimeric dialkylaluminium methylideneamide ( 5 ) which has two intact C=N double bonds. Up to now our attempts to insert a C=N double bond into an Al–C bond remained unsuccessful, and only the formation of an adduct [(Me₃C)₃Al(–N=CMe₂)₂] ( 6 ) was observed upon treatment of tri(tert‐butyl)aluminium with the diazabutadiene derivative.     

Bimetallic Rare Earth Alkyl Complexes Bearing Bridged Amidinate Ligands: Synthesis and Activity for L-Lactide Polymerization

Four novel bridged‐amidines H₂L {1,4‐R¹[C(=NR²)(NHR²)]₂ [R¹=C₆H₄, R²=2,6‐ⁱPr₂C₆H₃ (H₂L¹); R¹=C₆H₄, R²=2,6‐Me₂C₆H₃ (H₂L²); R¹=C₆H₁₀, R²=2,6‐ⁱPr₂C₆H₃ (H₂L³); R¹=C₆H₁₀, R²=2,6‐Me₂C₆H₃ (H₂L⁴)]} were synthesized in 65%–78% isolated yields by the condensation reaction of dicarboxylic acid with four equimolar amounts of amines in the presence of PPSE at 180°C. Alkane elimination reaction of Ln(CH₂SiMe₃)₃(THF)₂ (Ln=Y, Lu) with 0.5 equiv. of amidine in THF at room temperature afforded the corresponding bimetallic rare earth alkyl complexes (THF)(Me₃SiCH₂)₂LnL¹Ln(CH₂SiMe₃)₂(THF) [Ln=Y ( 1 ), Lu ( 2 )], (THF)(Me₃SiCH₂)₂LnL²Ln‐ (CH₂SiMe₃)₂(THF) [Ln=Y ( 3 ), Lu ( 4 )], (THF)(Me₃SiCH₂)₂YL³Y(CH₂SiMe₃)₂(THF) ( 5 ), (THF)(Me₃SiCH₂)₂YL⁴‐ Y(CH₂SiMe₃)₂(THF) ( 6 ) in 72% –80% isolated yields. These neutral complexes showed activity towards L‐lactide polymerization in toluene at 70°C to give high molecular weight (M>10⁴) and narrow molecular weight distribution (M_w/M_n≦1.40) polymers     

Synthesis of bulky tris[(dimethyl(alkyl/aryl)silyl)methyl]stannanes as radical based reducing agents

The synthesis of novel bulky tris[dimethyl(ethyl/benzyl/p-tolyl/α-naphthyl)silylmethyl]stannanes (1-4) is described. Alkylation of SnCl₄ with Me₂(ethyl/p-tolyl)SiCH₂MgBr (10-11) gave mainly the triorganotin chlorides [(Me₂(ethyl/p-tolyl)SiCH₂)]₃SnCl 14 and 15, which were isolated by silica gel chromatography. Reduction of 14 and 15 with LiAlH₄ in THF gave the corresponding triorganotin hydrides 1 and 2, respectively. [Me₂(benzyl/α-naphthyl)SiCH₂]₃SnCl 16 and 17, generated by the alkylation of SnCl₄ with Me₂(benzyl/α-naphthyl)SiCH₂MgBr 12 and 13, were inseparable from the minor product [Me₂(benzyl/α-naphthyl)SiCH₂]₂SnCl₂18 and 19, respectively. Treatment of the mixtures of 16/18 and 17/19 with NaOH furnished the corresponding mixtures of stannoxanes, from which the hexakisdistannoxanes [Me₂(benzyl/α-naphthyl)SiCH₂]₆Sn₂O 20 and 22 were isolated from the minor dialkyltin oxide derivatives [Me₂(benzyl/α-naphthyl)SiCH₂]₂SnO in good yields. Reduction of 20 and 22 with BH₃ in THF gave [Me₂(benzyl/α-naphthyl)SiCH₂]₃SnH (3 and 4), respectively in good yields. ¹H, ¹³C, ¹¹⁹Sn, ²⁹Si NMR characteristics of the newly synthesized compounds are included.     

Synthesis and molecular structure of chlorotris(trimethylsilylmethyl)trimethylsilyl-methylidyne rhenium(VII)

The complex Re(CSiMe₃)(CH₂SiMe₃)₃Cl has been isolated as yellow crystals in low yield from the reaction of ReCl₄(THF)₂ with Me₃SiCH₂MgCl and characterised by X-ray crystallography. The molecule has a trigonal bipyramidal geometry with the alkylidyne and chlorine ligands axial.