Reaction Of Trimethylaluminium Research Articles

Alkylsilazalanes. Reaction of trimethylaluminium with silazanes: Synthesis and molecular structure of [Al(CH 3) 2] 2[C 12H 32N 2Si 4] and [Al(CH 3) 2] 2[C 8H 28N 2Si 4

The crystalline product [Al(CH 3) 2] 2[C 12H 32N 2Si 4] ( I), obtained from reaction of 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentane with trimethylaluminium in a heptane-chlorobenzene mixture, crystallizes in the orthorhombic space group Pbca (No. 61) with unit-cell parameters a = 15.393(3), b = 12.987(2), c = 13.189(4) Å, V = 2637.4(2) Å 3 and D c = 1.06 g cm −3 for Z = 4. Full-matrix least-squares refinement based on 1549 observed reflections with intensities in the range 4.00 < 2θ < 50.0° converged at R = 0.048 ( R w = 0.064). Compound I resides about a crystallographic centre of symmetry and contains a planar Al 2N 2 four-membered ring with an Al⋯Al contact of 2.790(3) Å. Reaction of trimethylaluminium with 1,1,3,3-tetramethyldisilazane in heptane affords the crystalline product [Al(CH 3) 2] 2[C 8H 28N 2Si 4] ( II). Compound II crystallizes in the triclinic space group P 1 (No. 2) with unit-cell parameters a = 9.354(2), b = 14.670(3), c = 17.536(4) Å, α = 91.24(2), β = 90.63(2), γ = 99.46(2)°, V = 2372.7(9) Å 3 and D c = 1.06 g cm −3 for Z = 4. Full-matrix least-squares refinement based upon 5033 observed reflections with intensities in the range 3.50 < 2θ < 45.0° converged at R = 0.035 ( R w = 0.048). The mean Al ⋯ Al contact across the Al 2N 2 four-membered ring in II is 2.813(1) Å. The mean AlN bond distance in I is 2.005(3) Å while the mean AlN bond distance in II is 1.992(3) Å.

Reaction of trimethylaluminium with a tridentate open-chain amine. Synthesis and molecular structure of [Al(CH 3)] 2[C 12H 28N 6][Al(CH 3) 2] 2

Reaction of 3,3′-iminobispropylamine with trimethylaluminium affords the crystalline complex [Al(CH 3)] 2[C 12H 28N 6][Al(CH 3) 2] 2. The title compound crystallizes in the monoclinic space group P2 1/ n, with unit cell parameters a = 8.334(2), b = 11.099(3), c = 14.264(4) Å, β = 90.99(2)°, V = 1319.2 A 3, and ϱ = 1.14 g cm −3 for Z = 2. Least-squares refinement based on 1018 observed reflections [ I > 3σ( I)] converged at R = 0.048, R w = 0.053. The title compound, consisting of two amine units bridged by four organoaluminium moieties, has extensive AlN association. The two central aluminium atoms are five-coordinate residing in trigonal bipyramidal environments. The compound contains three Al 2N 2 rings with a mean AlN distance of 1.990(4) Å. The shortest Al … Al contact of 2.830(2) Å does not suggest significant metal-metal interactions.

Radical reactions of trimethylaluminium with a sterically hindered chloro-nitroso-compound

Trimethylaluminium does not methylate 1-chloro-1-nitroso-2,2,6,6-tetramethylcyclohexane (I), but functions as an electron donor and initiator of radical that lead ultimately to products (II)–(V), oxime derivatives, and an imine as outlined in reaction (1). E.s.r. studies support the intermediacy of iminyl radical (VI) which can undergo ring opening to the cyano-substituted radical (VII). For a kinetic e.s.r. study of this isomerisation the iminyl radical (VI) was generated from the diphenylmethyl oxime ether (XI) by reaction with t-butoxyl radicals. Combination of radical (VII) with iminoxyl radicals gives rise to the oxime ether (IV). The same product can be obtained by photolysis of the oxalate (XIII) and this supports the radical nature of the process.

Proton magnetic resonance evidence for the dimethylaluminium hydroxide

The reaction of trimethylaluminium with water has been studied. It was carried out in etheral solvents with a 2 : 1 mol ration of reactants. The resonance of protons of the hydroxyl groups bonded to aluminium was observed. On the basis of the properties of hydrogen bonding the structures of complexes between dimethylaluminiumhydroxide and the solvent have been proposed.

The reaction of trimethyllaluminum with lead sulfide

The reaction of trimethylaluminium with lead sulphide gives tetramethyl-lead, lead and bis(dimethylaluminium) sulphide. Under the experimental conditions the maximum degree of conversion of the methyl groups was 22.5% (0.5 h, 135°). The products were analysed by NMR spectroscopy.

Synthesis and some properties of bis(dimethylaluminium) sulphide

Bis(dimethylaluminium) sulphide, (Me 2Al) 2S, was prepared by a reaction of trimethylaluminium with liquid hydrogen sulphide. The compound is sparingly soluble in aromatic and aliphatic hydrocarbons and soluble in pyridine, benzonitrile and dioxane. The formation of a bis(dimethylaluminium) sulphide/benzonitrile complex has been studied and its relative acid strength compared with those of trimethylaluminium, dimethylaluminium chloride, and methylaluminium dichloride.

Reaction of trimethylaluminium with lead monoxide

At elevated temperatures, trimethylaluminium reacts with yellow lead oxide to yield tetramethyllead and bis(dimethylaluminium) oxide. The reaction proceeds according to the equation: 4 Me 3Al+2 PbO → Me 4Pb+Pb+2 (Me 2Al) 2O Under the experimental conditions, only one of the trimethylaluminium methyl groups produces a PbC bond (tetramethyllead). The observed maximum conversions of methyl groups were 25.9% (8 h; 135°) and 28.1% (140 h; 80°). In addition to tetramethyllead, the reaction of trimethylaluminium with yellow lead oxide affords some dimethylmethoxyaluminium. Lewis bases, if present in the reaction mixture, inhibit the synthesis of tetramethyllead. The reaction products have been studied by NMR and IR spectral methods and by quantitative analysis.

Darstellung und schwingungsspektren der trimethyl-aluminium-pseudohalogeno-komplexe [(Me 3Al) 2SCN] −, [Me 3AlSCN] −, [(Me 3Al) 2SeCN] − und [(Me 3Al) 2CN] −

By reaction of trimethylaluminium with NMe 4X (X  SCN, SeCN, CN) the complexes listed in the title can be prepared. According to the vibrational spectra (IR and Raman) the AlMe 3 molecules are coordinated to S and Se atoms, respectively, whereas in the case of cyanide ion both C and N atoms are coordinated symmetrically to AlMe 3.

Reactions of methylaluminium compounds with methacrylonitrile

Reactions of trimethylaluminium, dimethylaluminium chloride and methylaluminium dichloride with methacrylonitrile have been investigated. These reactions afford corresponding donor-acceptor complexes. At elevated temperatures they react to yield methyl isopropenyl ketone (upon hydrolysis) and oligomers. During these reactions methane is formed in small amounts. The yield of reaction products has been studied in relation to the nature of methylaluminium compound and the reaction temperature.

Reactions of methylaluminium compounds with acrylonitrile

The reactions of trimethylaluminium, dimethylaluminium chloride, and methylaluminium dichloride with acrylonitrile have been investigated. They have been found to afford equimolecular donor-acceptor complexes. The complexes react at elevated temperatures to yield methane and derivatives of dihydro and hexahydro-pyrimidine. The yields of the products of the methylaluminium compounds investigated have been studied in relation to the reaction temperature. Reaction mechanisms have been discussed in terms of the data obtained.

Hemi-alkoxides from reactions of trimethylaluminium with aldehydes or ketones

One mole of an aldehyde or ketone reacts stoicheiometrically with one mole of trimethylaluminium dimer at ambient temperature in hydrocarbon solvents to form a "hemi-alkoxide" in which an alkoxy group and a methyl group bridge two aluminium atoms. Benzaldehyde, acetone, acetophenone, benzophenone, and cyclohexanone give p-alkoxy-p-methyl-tetramethyldialuminiums (Me2A1.OR.Me.AlMe2; R = CHPhMe, But, CphMea2 CPh2Me, and 1-methylcyclohexyl, respectively). Such compounds can also be prepared in low yields starting from alcohols, rather than aldehydes or ketones. The analogous compound, NezAl.N=CPhMe.Me.AlMez, is formed by reaction of benzonitrile with one mole of trimethylaluminium dimer in the absence of solvent at 100�. Exchange of methyl groups between bridge and terminal sites in these new compounds has been studied by proton magnetic resonance spectroscopy.

Reactions of organoaluminium compounds with cyanides. Part III. Reactions of trimethylaluminium, triethylaluminium, dimethylaluminium hydride, and diethylaluminium hydride with dimethylcyanamide

Dimethylcyanamide reacts with trimethyl- and triethyl-aluminium to form adducts, Me2NC⋮N,AlR3, the i.r. spectra of which show that co-ordination occurs through the cyanide nitrogen. At 115° in a sealed tube, Me2NC⋮N,AlMe3 suffers extensive decomposition to methane, (Me2AlNMe2)2, and polymeric materials, whereas Me2NC⋮N,AlEt3 loses ethylene and rearranges to the dimeric formamidino-derivative (Me2NCH:NAlEt2)2. This last, like its methyl analogue (Me2NCH:NAlMe2)2, is better prepared from Me2NC⋮N +⅓(R2AlH)3, and is believed to have a structure based on an (AlN)2 four-membered ring. Features of the i.r. and 1H n.m.r. spectra of the dimethylcyanamide adducts and formamidino-derivatives are discussed.

β-Dianils from reaction of trimethylaluminium with benzanilides

β-Dianils from reaction of trimethylaluminium with benzanilides

591. Trimethylgallium. Part V. The reactions of trimethylaluminium, -gallium, and -indium with some primary and secondary phosphines and arsines

The first page of this article is displayed as the abstract.

Organoaluminium compounds. IX. Inhibition by coordinating solvents of the reaction of trimethylaluminium with triethylaluminium

Reaction of trimethylaluminium with triethylaluminium to give dimethylethylaluminium and methyldiethylaluminium is complete within a few seconds in mixtures of benzene with ether or tetrahydrofuran at 40�. Reaction in pyridine occurs more slowly and requires several minutes at 90�.