The synthesis and X-ray structure of the first exclusively N-based tetrameric complex [RAl]4 (1; R = 2,6-iPr2C6H3N(SiMe3)) are reported. 1 was prepared by the reduction of [RAlI2]2 (2) with Na/K alloy.
The reaction of AlH(3).NMe(3) with RCN proceeds with the evolution of trimethylamine and affords (HAINCH(2)R)(6) (R = Ph (1), p-MeC(6)H(4) (2), p-CF(3)C(6)H(4) (3)). Compounds 1 and 3 are characterized by single-crystal structural analysis. Compound 1 reacts with Me(3)SiBr as well as with PhC[triple bond]CH to give (XAINCH(2)Ph)(6) (X = Br (4), PhC[triple bond]C (5)). Structural data and other characterization data of compounds 4 and 5 show that all the hydridic hydrogen atoms in 1 have been replaced by bromine atoms and PhC[triple bond]C groups, respectively. Compounds 1-5 are potential precursors for the preparation of aluminum nitride. Crystals of 1 are rhombohedral, space group R3 macro, with a = 15.7457(13) A, b = 15.7457(13) A, c = 14.949(2) A, V = 3209.8(5) A(3), and Z = 3. Crystals of 3.(3)/(4)C(7)H(8) are triclinic, space group P1 macro, with a = 17.527(11) A, b = 18.894(12) A, c = 19.246(15) A, alpha = 96.11(7) degrees, beta = 102.23(4) degrees, gamma = 106.79(3) degrees, V = 5867(7) A(3), and Z = 4. Compound 4 crystallizes in the monoclinic space group P2(1)/c, with a = 14.175(4) A, b = 16.678(5) A, c = 10.731(3) A, beta = 106.82(2) degrees, V = 2428.6(11) A(3), and Z = 2. Compound 5. C(7)H(8) crystallizes in the monoclinic space group C2/c, with a = 25.842(5) A, b = 15.443(3) A, c = 20.699(4) A, beta = 105.88(3) degrees, V = 7945(3) A(3), and Z = 4.
The synthesis and characterization of 1,5bis(2,6-diisopropylphenyl)-2,4-diphenyl-1,3,5-triazapenta-1,3diene (L 1 H), a triaza ligand, and Al complexes of its anion are reported. A neat condensation reaction between N-(Dipp)benzamidine (Dipp = 2,6-diisopropylphenyl) and N-(Dipp)benzimidoyl chloride affords L 1 H in good yield. The Al complexes [L 1 AlMe 2 ] (1), [L 1 AlMe(Cl)] (2), and [L 1 AlCl 2 ] (3) are prepared by treating L 1 H with a slight excess of AlMe 3 , AlMe 2 Cl, and AlMeCl 2 , respectively, in toluene. Further, the aluminum complexes [L 2 AlMe 2 ] (5), [L 2 AlMe(Cl)] ( 6), and [L 2 AlCl 2 ] (7) are obtained in good yields from 1,3-bis(2pyridylimino)isoindoline (L 2 H) in a similar fashion. The ligand L 1 H and complexes 1, 2, and 4−6 have been structurally characterized. All of the complexes have been explored for their catalytic activity toward the ring-opening polymerization (ROP) of ε-caprolactone. It has been found that [L 1 AlMe 2 ], upon the addition of cocatalyst (benzyl alcohol), gives a tetranuclear Al alkoxide (8), which is highly efficient in catalyzing the ROP of ε-caprolactone. [L 2 AlMe 2 ] has also been found to be a good catalyst. The crystal structure of 8 and the catalytic activities of all the complexes in detail are reported.
Reactions of the dilithiated diols RCH2P(S)(CH2OLi)2 [R = Fc (1), Ph (2) (Fc = ferrocenyl)] with N3P3F6 in equimolar ratios at -80 degrees C result exclusively in the formation of two structural isomers of ansa-substituted compounds, endo-RCH2P(S)(CH2O)2[P(F)N]2(F2PN) [R = Fc (3a), Ph (4a)] and exo-RCH2P(S)(CH2O)2[P(F)N]2(F2PN) [R = Fc (3b), Ph (4b)], which are separated by column chromatography. Increasing the reaction temperature to -40 degrees C results in more of the exo isomers 3b and 4b at the expense of the endo isomers. The formation of the ansa-substituted compounds is found to depend on the dilithiation of the diols, as a reaction of the silylated phosphine sulfide FcCH2P(S)(CH2OSiMe3)2 (5) with N3P3F6 in the presence of CsF does not yield either 3a or 3b but instead gives the spiro isomer [FcCH2P(S)(CH2O)2 PN](F2PN)2 (6) as the disubstitution product of N3P3F6. The ansa isomers 3a and 3b are transformed into the spiro compound 6 in the presence of catalytic amounts of CsF at room temperature in THF, while 4a and 4b are transformed into the spiro compound [PhCH2P(S)(CH2O)2PN](F2PN)2 (7) under similar conditions. The novel conversions of ansa-substituted phosphazenes into spirocyclic phosphazenes were monitored by time-dependent 31P NMR spectroscopy. The effect of temperature on a transformation was studied by carrying out reactions at various temperatures in the range from -60 to +33 degrees C for 3b. In addition, compounds 3a, 3b, 4a, and 6 were structurally characterized. In the case of the ansa compounds, the nitrogen atom flanked by the bridging phosphorus sites was found to deviate significantly from the plane defined by the five remaining atoms of the phosphazene ring.
The syntheses of the ionic compounds [Li(+).2 dioxane (2,6-iPr(2)C(6)H(3)N(SiMe(3))Al(C triplebond CSiMe(3))(3))(-)].0.75 dioxane (1), [(Li(+))(2).(dioxane)(7)](0.5) [2,6-iPr(2)C(6)H(3)N(SiMe(3))Ga(C triplebond CSiMe(3))(3)(-)].1.5 dioxane (2), and [(Li(+))(2).(dioxane)(7)](0.5) [2,6-iPr(2)C(6)H(3)N(SiMe(3))In(C triplebond CSiMe(3))(3)(-)].1.5 dioxane (3) by the reaction of the corresponding organo metal chloride with LiC triplebond CSiMe(3) are reported. The neutral ethynyl compounds Br-Al(C triplebond CtBu)(2).2 THF (4), Cl-Ga(C triplebond CtBu)(2).THF (5), Cl-In(C triplebond CtBu)(2).2 THF (6), Al(C triplebond CtBu)(3).C[N(Me)CMe](2) (7), Ga(C triplebond CtBu)(3).dioxane (8), and In(C triplebond CtBu)(3).NEt(3) (9) have been obtained in good yields from the reaction of AlBr(3), GaCl(3), and InCl(3) with LiC triplebond CtBu in the presence of a Lewis base. Compound 7 is the first heterocyclic carbene substituted ethynyl derivative. Aluminum and gallium compounds with three terminal ethynyl groups Al(C triplebond CPh)(3).NMe(3) (10) and Ga(C triplebond CPh)(3).NMe(3) (11) have been prepared by the reaction of AlH(3).NMe(3) or GaH(3).NMe(3) with three equivalents of phenylethyne. All the above-mentioned compounds have been structurally studied. In compound 1 the lithium ion is coordinated to the three terminal ethynyl groups, whereas in compounds 2 and 3 the lithium is coordinated to the solvent (dioxane). Compound 8 crystallizes as a coordination polymer with dioxane molecules bridging the individual gallium units.
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