Guanidinate borohydride derivatives of lanthanides: synthesis and molecular structures of the [(Me3Si)2NC(NCy)2]Gd(BH4)2DME and [{(Me3Si)2NC(NPri)2}2Sm(BH4)2]−[Li(DME)3]+ complexes. Catalytic activity of the [(Me3Si)2NC(NCy)2]2Ln(BH4)2Li(THF)2 complexes (Ln = Nd, Sm, or Yb) in methyl methacrylate polymerization

The reaction of Gd(BH₄)₃(THF)₂ with two equivalents of sodium N,N′-dicyclohexyl-N″-bis(trimethylsilyl)guanidinate in THF followed by the treatment of the reaction product with 1,2-dimethoxyethane produced the monoguanidinate bis(borohydride) complex [(Me₃Si)₂NC(NCy)₂]Gd(BH₄)₂DME (1) (Cy is cyclohexyl). The treatment of the heterobimetallic samarium complex {(Me₃Si)₂NC(NPrⁱ)₂}₂Sm(BH₄)₂Li(THF)₂, in which the lanthanide and lithium atoms are linked by two bridging borohydride groups, with 1,2-dimethoxyethane afforded the ionic complex [{(Me₃Si)₂NC(NPrⁱ)₂}₂Sm(BH₄)₂]^?[Li(DME)₃]⁺ (2). The structures of complexes 1 and 2 were established by X-ray diffraction. The [(Me₃Si)₂NC(NCy)₂]₂Ln(BH₄)₂Li(THF)₂ complexes (Ln = Nd (3), Sm (4), or Yb (5)) were found to catalyze methyl methacrylate polymerization.     

Syntheses and molecular structures of mono(guanidinate) lanthanide borohydrides and their catalytic activity for MMA-polymerization

The mono(guanidinate) lanthanide borohydride complexes of [(Me₃Si)₂NC(NCy)₂]Ln(BH₄)₂(THF)₂ (Ln = Yb (1), Er (2)) have been synthesized by the reactions of corresponding Ln(BH₄)₃(THF)₃ with sodium guanidinate of [(Me₃Si)₂NC(NCy)₂]Na in a 1:1 molar ratio in THF. They were characterized by elemental analysis, infrared spectrum and X-ray diffraction analysis. 1 and 2 have similar structures. The lanthanide ion was bonded by an η²-guanidinate ligand, two η³-BH₄ ligands and two THF molecules as a distorted octahedron. The two BH₄ ligands in a complex are equivalent and cis to each other. The structure of solvated sodium guanidinate of {[(Me₃Si)₂NC(NCy)₂]Na(THF)}₂ (3) was also presented. In a dimeric molecule of 3, each Na atom is bound to three nitrogen atoms from two guanidinate groups and one oxygen atom from the THF molecule. 1 and 2 displayed moderate high catalytic activity for the polymerization of methyl methacrylate. The Er complex is more active than the Yb complex.     

Mixed-ligand guanidinate derivatives of rare-earth metals. Molecular structures of { (Me3Si)2NC(N-cyclo-Hex)2}Y[N(SiMe3)2]2, [{ (Me3Si)2NC(N-cyclo-Hex)2}YbI(THF)2]2, and [{(Me3Si)2N} Y(THF)(µ-Cl)]2 complexes

The insertion of N,N′-dicyclohexylcarbodiimide at one of the Y-N bonds of the [(Me₃Si)₂N]₃Y complex in toluene at 70 °C afforded the monoguanidinate diamide derivative { (Me₃Si)₂NC(N-cyclo-Hex)₂}Y[N(SiMe)₃]₂ (1) (cyclo-Hex is cyclohexyl) in 72% yield. The reaction of equimolar amounts of sodium N,N′-dicyclohexyl-N″-bis(trimethylsilyl)guanidinate, which was prepared in situ from {(Me₃Si)₂N}Na and N,N′-dicyclohexylcarbodiimide, and YbI₂(THF)₂ in THF gave the [{(Me₃Si)₂NC(N-cyclo-Hex)₂}YbI(THF)₂]₂ complex (2). An attempt to use this procedure for the synthesis of the yttrium compound { (Me₃Si)₂NC(NSiMe₃)₂}₂YCl containing the sterically more hindered guanidinate ligand unexpectedly led to the formation of the diamide chloride complex [{(Me₃Si)₂N}₂Y(THF)(µ-Cl)]₂ (3). The structures of complexes 1–3 were established by X-ray diffraction. Compound 1 is mononuclear. Complexes 2 and 3 are dinuclear and contain two µ²-bridging halide ligands.     

Synthesis and properties of guanidinate derivatives of rare-earth metals. Molecular structures of the { (Me3Si)2NC(NPri)2}2Y(µ-Cl)2Li(THF)2, [{ (Me3Si)2NC(NPri)2}2SmCl]2 and {(Me3Si)2NC(NPri)2} Sm(µ3-BH4)2(DME) complexes

The reaction of anhydrous SmCl₃ with two equivalents of lithium N,N′-diisopropyl-N″-bis(trimethylsilyl)guanidinate in THF afforded the [{(Me₃Si)₂NC(NPrⁱ)₂}₂SmCl]₂ complex (1) in 82% yield. Analogous reactions with YCl₃ and GdCl₃ produced the ate-complexes { (Me₃Si)₂NC(NPrⁱ)₂}₂Ln(µ-Cl)₂Li(THF)₂ (Ln = Y (2) and Gd (3)). The structures of complexes 1 and 2 were established by X-ray diffraction. The reaction of complex 1 with NaBH₄ in hexane (20 °C) followed by treatment with dimethoxyethane yielded the unexpected product, { (Me₃Si)₂NC(NPrⁱ)₂}Sm(µ³-BH₄)₂(DME) (5). X-ray diffraction study showed that both borohydride ligands in complex 5 are tridentate.     

Postmetallocene lanthanide-hydrido chemistry: A new family of complexes [{Ln{(Me3Si)2NC(NiPr)2}2(mu-H)}2] (Ln = Y, Nd, Sm, Gd, Yb) supported by guanidinate ligands-synthesis, structure, and catalytic activity in olefin polymerization

The new family of Lewis base free hydrido complexes of rare-earth metals supported by guanidinate ligands [{Ln{(Me3Si)2NC(NiPr)2}2(mu-H)}2] (Ln = Y, Nd, Sm, Gd, Yb) was synthesized and structurally characterized. Single-crystal X-ray and solution NMR studies revealed that these complexes are dimeric in both solid state and in [D6]benzene. The dimeric hydrido complexes can adopt eclipsed (Nd, Sm, Gd) or staggered (Y, Yb, Lu) conformations depending on the metal-atom size. Catalytic activity of these [{Ln{(Me3Si)2NC(NiPr)2}2(mu-H)}2] complexes in the polymerization of ethylene, propylene, and styrene has been investigated. Complexes of Sm and Y have high catalytic activity in ethylene polymerization (1268 and 442 g mmol(-1) atm(-1) h(-1), respectively).     

Rare-earth metal amido complexes supported by bridged bis(β-diketiminato) ligand as efficient catalysts for hydrophosphonylation of aldehydes and ketones

A series of rare-earth metal amides supported by a cyclohexyl-linked bis(β-diketiminato) ligand were synthesized,and their catalytic activities for hydrophosphonylation of aldehydes and ketones were developed.Reaction of [(Me3Si)2N]3 RE(Cl)Li(THF)3 with the cyclohexyl-linked bis(-diketimine) H2L(1)(L=Cy[NC(Me)CHC(Me)NAr]2,Cy = cyclohexyl,Ar=2,6-i-Pr2C6H3) gave the rare-earth metal amides LREN(SiMe3)2(RE = Nd(2),Sm(3),Dy(4),Er(5),Y(6)).All complexes were fully characterized by elemental,spectroscopic and single-crystal X-ray analyses.Investigation of the catalytic properties of the complexes reveals that these complexes exhibited a high catalytic activity towards the hydrophosphonylation of aldehydes and ketones in the presence of a very low loading of rare-earth metal amides(0.1-1 mol%) at room temperature in a short time.     

N,N'-diisopropyl-N'-bis(trimethylsilyl)guanidinate ligand as a supporting coordination environment in yttrium chemistry. Synthesis, structure, and properties of complexes [(Me(3)Si)(2)NC(Ni-Pr)(2)]YCl(2)(THF)(2), [(Me(3)Si)(2)NC(Ni-Pr)(2)]Y(CH(2)SiMe(3))(2)(THF)(2), and [(Me(3)Si)(2)NC(Ni-Pr)(2)]Y[(mu-H)(mu-Et)(2)BEt](2)(THF)

The reaction of anhydrous YCl3 with an equimolar amount of lithium N,N'-diisopropyl-N' '-bis(trimethylsilyl)guanidinate, Li[(Me3Si)2NC(Ni-Pr)2], in tetrahydrofuran (THF) afforded the monomeric monoguanidinate dichloro complex {(Me3Si)2NC(Ni-Pr)2}YCl2(THF)2 (1). Alkylation of complex 1 with 2 equiv of LiCH2SiMe3 in hexane at 0 degrees C yielded the monomeric salt-free dialkyl complex {(Me3Si)2NC(Ni-Pr)2}Y(CH2SiMe3)2(THF)2 (2). The bis(triethylborohydride) complex [(Me3Si)2NC(Ni-Pr)2]Y[(mu-H)(mu-Et)2BEt]2(THF) (5) was prepared by the reaction of complex 1 with 2 equiv of LiBEt3H in a toluene-THF mixture at 0 degrees C. The complexes 1, 2, and 5 were structurally characterized. Complex 2 as well as the systems 2-Ph3B, 2-Ph3B-MAO, and 1-MAO (MAO = methylaluminoxanes) in toluene were inactive in ethylene polymerization, while the product obtained in situ from the reaction of complex 2 with a 2-fold molar excess of PhSiH3 in toluene polymerized ethylene with moderate activity.     

Bulk polymerization of rac-lactide initiated by guanidinate alkoxide complexes of rare earth metals. The molecular structure of the cluster [{(Me3Si)2NC(NPri)2}Nd]4(μ3-OPri)8Li7(μ2-Cl)3(μ3-Cl)2(μ4-Cl)2

The complexes {(Me₃Si)₂NC(NPrⁱ)₂}₂LnOBu^t (Ln = Y (1), Lu (2)) initiate the bulk polymerization of racemic lactide (LA) at 130 °C. At the monomer: initiator molar ratio ([LA]: 1) equal to 1000: 1, the quantitative conversion of the monomer is achieved within 6 h. The resulting polymers are characterized by a rather narrow monomodal molecular weight distribution (M _w/M _n = 1.46–1.82) and molecular weights up to 33400 g mol^?1. The molecular weights of the resulting polylactides measured by gel permeation chromatography are 3–11 times lower than the values calculated from the monomer: initiator ratio on the assumption of one growing polymer chain per catalytic center. The reaction of the in-situ prepared complex [(Me₃Si)₂NC(NPrⁱ)₂]NdCl₂ with 2 equiv. of PrⁱOLi produced the 11-nuclear cluster [{(Me₃Si)₂NC(NPrⁱ)₂}Nd]₄(μ³-OPrⁱ)₈Li₇(μ²-Cl)₃(μ³-Cl)₂(μ⁴-Cl)₂ (3), which was isolated in 62% yield. The structure of compound 3 was established by X-ray diffraction. Complex 3 initiates both the bulk and solution polymerization of rac-lactide. In the bulk polymerization at the molar ratio [LA]: [Nd] = 500: 1, the 89% conversion of the monomer was achieved within one hour. The polylactide thus synthesized has the molecular weight M _n = 19720 g mol^?1 and a rather narrow polydispersity M _w/M _n = 1.54.     

Synthesis, characterization of homoleptic guanidino lanthanide complexes and their catalytic activity for the ring-opening polymerization of ε-caprolactone

A series of homoleptic lanthanide guanidinate (guan)₃Ln · ((C₂H₅)₂O)_n (Ln=Yb, n=1 guan=(CyN)₂CNiPr₂, (1); Ln=Nd, n=0, guan=(CyN)₂CNiPr₂, (2); (iPrN)₂CNiPr₂, (3); (iPrN)₂CN(CH₂)₅, (4)); (iPr=isopropyl, Cy=Cyclohexyl) were synthesized by the reaction of THF solution of lithium guanidinate with anhydrous lanthanide trichlorides in THF in 3:1 molar ratio. The molecular structures of 2 and 3 were determined to be monomeric in solid state with a six coordinate lanthanide metal ligated by six nitrogens of three guanidinate groups. All the complexes exhibited extremely high activity for the ring-opening polymerization of ε-caprolactone and the polymerization gave the polymers with high molecular weights. The different substituents at guanidino ligands have great effect on the catalytic activity. The mechanism of the polymerization was presented.     

Five-, six- and eight-membered ring organosilicon chalcogenides of the types Z2(SiMe2)2E (Z = Me2Si, H2C; E = S, Se, Te), Z(SiMe2E)2MR2 (Z = Me2Si, H2C, O; E = S, Se, Te; M = Si, Ge, Sn, R = Me, Ph) and (SiMe2ZSiMe2E)2 (Z = Me2Si, H2C; E = S, Se)

Reactions of ClMe₂Si–Z–SiMe₂Cl (Z = SiMe₂ (1a), CH₂ (1c), O (1e)) with Li₂E (E = S, Se) yielded eight-membered ring compounds (SiMe₂ZSiMe₂E)₂ (3a–d) as well as acyclic oligomers (SiMe₂ZSiMe₂E)_x of different chain lengths. If 1:1 molar mixtures of 1a, 1c or 1e and a diorganodichlorosilane, -germane or -stannane (R₂MCl₂) are reacted with Li₂E (E = S, Se, Te), six-membered ring compounds Z(SiMe₂E)₂MR₂ (4a–7g) are formed exclusively. Five-membered rings Z₂(SiMe₂)₂E (Z = SiMe₂ (8a–c), CH₂ (9a–c); E = S, Se, Te) are obtained starting from the tetrasilane ClMe₂Si–(SiMe₂)₂–SiMe₂Cl (1b) or the disilylethane ClMe₂Si–(CH₂)₂–SiMe₂Cl (1d) by treatment with Li₂E. All products were characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ²⁹Si, ¹¹⁹Sn, ⁷⁷Se, ¹²⁵Te, including coupling constants) and the effects of the different ring sizes towards NMR chemical shifts are discussed.     

Photochemical synthesis of a palladium dichloromethyl complex, {(hexyl)HC(N-methyl-imidazol-2-yl)2}Pd(CHCl2)Cl.: X-ray molecular structures of {(hexyl)HC(N-methylimidazolyl-2-yl)2}Pd(X)Cl, X=Cl, and CHCl2

The reaction of (hexyl)HC(mim)₂ (1, mim=N-methyl-imidazol-2-yl) with (cod)PdMeCl in C₆H₆ yields {(hexyl)HC(mim)₂}Pd(Me)Cl (3). The photochemical reaction of 3 with CH₂Cl₂ at 23 °C in ambient room light yields {(hexyl)HC(mim)₂}Pd(CHCl₂)Cl (4). It is proposed that this reaction proceeds by homolytic scission of the PdMe bond of 3.     

σ-Bonded organometallic derivatives of yttrium(III) and thulium(III): An unusual ligand coupling reaction mediated by thulium(III)

The reaction between LnI₃(THF)_3.5 and 2 equiv. of {(Me₃Si)₂(Me₂MeOSi)C}K (1) in THF at room temperature yields only the mono-substituted products {(Me₃Si)₂(Me₂MeOSi)C}LnI₂(THF)₂ [Ln = Y (5), Tm (6)]; under more forcing conditions decomposition occurs. In contrast, the metathesis reaction between TmI₃(THF)_3.5 and 2 equiv. of the lithium iodide-containing salt {(Me₃Si)₂(Me₂MeOSi)C}K(LiI)_x yields the highly unusual separated ion pair complex [[{(Me₃Si)₂C(SiMe₂)}₂O]TmI₂{Li(THF)₃}₂][[{(Me₃Si)₂C(SiMe₂)}₂O]TmI₂] (8). The dianionic ligand in 8 is derived from the coupling of 2 equiv. of (Me₃Si)₂(Me₂MeOSi)C⁻, accompanied by the formal elimination of Me₂O. The structures of compounds 5, 6, and 8 have been determined by X-ray crystallography; compound 8 crystallizes as an unusual ion pair, the cation and anion of which differ only in the inclusion of 2 equiv. of Li(THF)₃ in the former, bridged to thulium by iodide ions.     

Molecular geometry and electronic structures of stable organic derivatives of divalent germanium and tin [(\operatorname{Me} _3 \operatorname{Si} )_2 \operatorname{N} {\kern 1pt} ---{\kern 1pt} Me_2 ]_n (M = Ge, n = 1; M = Sn, n = 2): a theoretical study

The molecular geometry and electronic structure of stable organic derivatives of divalent germanium and tin, [(Me₃Si)₂N-M-OCH₂CH₂NMe₂]_n (M = Ge (4), n = 1; M = Sn (5), n =2) and their isomers with broken (4a, 5a) and closed (4b, 5b) intramolecular coordination bonds M←NMe₂, were studied by the density functional (PBE/TZ2P/SBK-JC) and NBO methods. Factors responsible for stability of their dimers 4c and 5c were established. Dimerization of 5b in the gas phase is a thermodynamically favorable process (ΔG ⁰ = ?2.1 kcal mol^?1) while that of 4b is thermally forbidden (ΔG ⁰ = 10.1 kcal mol^?1), which is consistent with experimental data. The M←NMe₂ coordination bond energies, ΔE ⁰, were found to be ?5.3 and ?8.6 kcal mol^?1 for M = Ge and Sn, respectively. NBO analysis showed that the metal atoms M in molecules 4 and 5 are weakly hybridized. The lone electron pairs of the M atoms have strong s-character while vacant orbitals of these atoms, LP* M, are represented exclusively by the metal np_z-AOs. The strongest orbital interactions between subunits in dimers 4c and 5c involve electron density donation from the lone electron pairs of oxygen atoms (LP O) to the LP* M orbitals.     

Reactivity of lanthanocene hydroxides toward carbodiimide and CO2: Synthesis and characterization of lanthanide ureido and carbonate complexes

[Cp₂Ln(μ-OH)(THF)]₂ react with 2 equiv of CyNCNCy (Cy = cyclohexyl) to form [Cp₂Ln(μ-OC(NHCy)NCy)]₂ (Ln = Er (1-Er), Y (1-Y)), while treatment of [Cp₂Ln(μ-OH)]₂(μ₃-O)LnCp(THF) with CyNCNCy affords the addition/rearrangement products [Cp₂Ln(μ₃-O)(μ-OC(NHCy)NCy)LnCp]₂ (Ln = Yb (3-Yb), Er (3-Er)). Compounds [(Cp₂Ln)₂(μ₃-CO₃)(THF)]₂ (Ln = Yb (4-Yb), Er (4-Er)) can be obtained by treatment of [Cp₂Ln(μ-OH)(THF)]₂ with CO₂ immediately followed by the reaction with the corresponding Cp₃Ln. Complexes 1-4 were characterized by elemental analysis, spectroscopic properties and X-ray single crystal diffraction analysis.     

Tris(trimethylsilyl)methane and tris(dimethylphenylsilyl)methane: Preparation and comparison of some alkene and cyclopropane derivatives

It is known that metalation of (RMe₂Si)₃CH (R: a = Me, b = Ph) with MeLi in THF yields (RMe₂Si)₃CLi, which when reacted with allyl bromide, (RMe₂Si)₃C-CH₂-CH=CH₂ (1a, 1b) are produced. In this study, although (PhMe₂Si)₃CLi does not react with benzyl bromide, under the same conditions (Me₃Si)₃CLi does, giving the expected product. We found that the bromination of 1b was unsuccessful and the reaction of 1a occurs in low yield due to severe steric hindrance. This idea is supported by our results, which show that, when treated with dichlorocarbene and dibromocarbene, 1a and 1b yield the related dihalocyclopropanes. Furthermore, reduction of the obtained products gives the dehalogenated compounds.     

One-dimensional lanthanide complexes bridged by nitronyl nitroxide radical ligands with non-chelating nitrogen donors: Structure and magnetic characterization

A series of new lanthanide-radical complexes [{Ln(hfac)3}2(NITPhIM)2] (Ln = Nd (1), Eu (2), Tb (3), Er (4); hfac = hexafluoroacetylacetonate; NITPhIM = 2-[4-(1-imidazole)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been prepared and characterized. Single crystal X-ray diffraction analyses reveal that these complexes are isostructural with one-dimensional chain structures. These consist in Ln(hfac)3 units bridged by the paramagnetic ligands by the means of coordination of their nitronyl nitroxide groups and imidazole rings. Interestingly, each Ln ion is either bound to two nitronyl nitroxide groups or to two imidazole units, and the different Ln centers alternate along the chain. Magnetic studies show that complex 3 exhibits a single-chain magnet behavior.     

Synthesis,reactivity and structural characterization of lanthanide hydroxides stabilized by a carbon-bridged bis(phenolate) ligand

The synthesis of lanthanide hydroxo complexes stabilized by a carbon-bridged bis(phenolate) ligand 2,2’-methylene-bis(6-tert-butyl-4-methylphenoxo) (MBMP²⁻) was described, and their reactivity toward phenyl isocyanate was explored. Reactions of (MBMP)Ln(C₅H₅)(THF)₂ with a molar equiv. of water in THF at −78 °C afforded the bis(phenolate) lanthanide hydroxides as dimers [{(MBMP)Ln(μ-OH)(THF)₂}₂] [Ln = Nd (1), Yb (2)] in high yields. Complexes 1 and 2 reacted with phenyl isocyanate in THF, after workup, to give the desired O−H addition products, [(MBMP)Ln(μ-η¹:η²-O₂CNHPh)(THF)₂]₂ [Ln = Nd (3), Yb (4)] in excellent isolated yields. These complexes were well characterized, and the molecular structures of complexes 2 to 4 were determined by X-ray crystallography. The ytterbium atom in complex 2 is coordinated to six oxygen atoms to form a distorted octahedral geometry, whereas each metal center in complexes 3 and 4 is seven-coordinated, and the coordination geometry can be best described as a distorted pentagonal bipyramid.     

Synthesis, molecular structure, and catalytic activity of borohydride complexes [(Me3Si)2NC(NPri)2]2Nd(BH4)2Li(thf)2 and [(Me3Si)2NC(NPri)2]2Sm(BH4)2Li(thf)2

The reactions of lanthanide tris(borohydrides) Ln(BH₄)₃(thf)₃ (Ln = Sm or Nd) with 2 equiv. of lithium N,N′-diisopropyl-N′-bis(trimethylsilyl)guanidinate in toluene produced the [(Me₃Si)₂NC(NPrⁱ)₂]Ln(BH₄)₂Li(thf)₂ complexes (Ln = Sm or Nd), which were isolated in 57 and 42% yields, respectively, by recrystallization from hexane. X-ray diffraction experiments and NMR and IR spectroscopic studies demonstrated that the reactions afford monomeric ate complexes, in which the lanthanide and lithium atoms are linked to each other by two bridging borohydride groups. The complexes exhibit catalytic activity in polymerization of methyl methacrylate. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 441–445, March, 2007.     

Arenechromiumtricarbonyl complexes of silyl(germyl)(stannyl)- and silyl(germyl)(plumbyl)methanes including the unexpected formation of arenechromiumtricarbonyldimethylsilanol, (η-C6H5)Cr(CO)3SiMe2OH

Treatment of PhMe₂SiCH₂GeMe₃ (1) with t-BuLi followed by addition of Me₃ECl, E = Sn, Pb, results in the formation of phenylsilyl(germyl)stannyl- and phenylsilyl(germyl)plumbyl-methanes, PhMe₂Si(Me₃Ge)(EMe₃)CH, E = Sn (2), Pb (3). The thermal reaction of 1, 2 and 3 with Cr(CO)₆ yields the corresponding aryl-Cr(CO)₃ analogs, {(η⁶-C₆H₅)Cr(CO)₃}Me₂Si(Me₃Ge)CH₂ (4) and {(η⁶-C₆H₅)Cr(CO)₃}Me₂Si(Me₃Ge)(EMe₃)CH, E = Sn (5), Pb (6). The thermal treatment of 2 with Cr(CO)₆ in a wet THF/di-n-butyl ether mixture results in the formation of the arenechromiumtricarbonyl silanol {(η⁶-C₆H₅)Cr(CO)₃}Me₂SiOH (7) which exhibits amphiphilic character, forming H-bonded chains in the solid state in a head-to-head arrangement of the areneCr(CO)₃ units.     

Synthesis and characterisation of [AlMen{Si(SiMe3)3}3−n(thf)] (n = 1 or 2)

The crystalline compounds [AlMe_n{Si(SiMe₃)₃}_3−n(thf)] [n = 2 (1) or 1 (2)] were prepared from the lithium sisyl [Li{Si(SiMe₃)₃}(thf)₃] (A) and the appropriate methylaluminium chloride [AlCl_3−nMe_n] in thf. The X-ray structure of 1 is reported. Unlike A or a magnesium sisyl [Mg{Si(SiMe₃)₃}₂(thf)₂] (B), neither 1 nor 2 underwent an insertion reaction with an α-H-free nitrile.