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The catalytic regioselective C–H silylation of a wide range of alkoxy-substituted benzene derivatives with primary hydrosilane was achieved by the use of scorpionate-supported calcium benzyl comple...

The first examples of scandium methylidyne complexes [(Cp*)Sc(μ2-X)]3(μ3-CH) (Cp* = C5Me5; X = Br, Me, OMe), free of Lewis acids, can be achieved in high yields from [(Cp*)ScMe2]2 through a facile route. The chemical and geometrical flexibility to incorporate organic substrates indicates a rich chemistry of complex [(Cp*)Sc(μ2-OMe)]3(μ3-CH).

Hydrogenolysis of the scorpionate-supported calcium benzyl complex [(TpAd,iPr)Ca(p-CH2C6H4-Me)(THP)] (TpAd,iPr = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate, THP = tetrahydropyran) (2-THP) afforded the mononuclear calcium hydrido complex [(TpAd,iPr)Ca(H)(THP)] (3). Under mild conditions (40 °C, 10 atm H2, 5 mol% cat.), complex 3 effectively catalyzed the hydrogenation of a variety of alkenes, including activated alkenes, semi-activated alkenes, non-activated terminal and internal alkenes. Mononuclear calcium unsubstituted alkyl complex [(TpAd,iPr)Ca{(CH2)4Ph}(THP)] (6), proposed as the catalytic hydrogenation intermediate, was isolated and structurally characterized.

International audience; The first mononuclear divalent ytterbium hydride complex [(Tp(Ad,iPr))Yb(H)(THF)] (Tp(Ad,iPr) = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate) (2) bearing a terminal hydrido ligand was obtained by hydrogenolysis of the benzyl precursor in hexane. Complex 2 exhibited two different reaction patterns towards allenes: Yb-H addition with cyclohexylallene and deprotonation of 1,1-dimethylallene.

International audience; Hydrogenolysis of the half-sandwich penta-arylcycopentadienyl-supported rare-earth metal dibenzyl complexes [(Cp-Ar5)Ln(p-CH2-C6H4-Me)(2)(THF)] (Cp-Ar5 = C5Ar5, Ar = 3,5-Pr-i(2)-C6H3; Ln = Sc, La) afforded a bimetallic scandium complex [(Cp-Ar5)Sc(H)(mu-OC4H9)](2) (2) with two terminal hydrido ligands, and a double-sandwich bimetallic lanthanum hydride complex [(Cp-Ar5)La(mu-H)](2) (4) bearing the reduced Cp-Ar5 ligand. DFT calculations were conducted to elucidate the reaction profiles.

A heteroleptic barium aminobenzyl complex [(TpAd,iPr)Ba(o-CH2C6H4-NMe2)] (1) was obtained in excellent yield from a simple one-pot reaction. Treatment of [(TpAd,iPr)Ba(o-CH2C6H4-NMe2)] (1) with two equivalents of AlR3 (R = Me, Et) led to the formation of barium tetraalkylaluminate complexes [(TpAd,iPr)Ba(AlR4)]n (R = Me, n = 2, 2; R = Et, n = 1, 3) as dimers or monomers in the solid state. The TpAd,iPr ligand-free peralkylated barium complex [Ba(AlEt4)2]n was isolated by the addition of ten equivalents of AlEt3 under the same conditions. The donor-induced aluminate cleavage is not applicable when donor solvents are added to complexes 2 and 3. In the solution of complexes 2 and 3, the alkylaluminate moieties and TpAd,iPr ligands show a rapid fluxional behavior in [D8]toluene solution over the temperature range of -70 to 25 °C, without any significant decoalescence of the corresponding proton signals.

International audience; The monomeric actinide dihydrido complex [(Cp-Ar*)(Cp*)ThH2(THF)] (2) bearing the super-bulky penta-arylcyclopentadienyl (Cp-Ar* = C5Ar*(5), Ar* = 3,5-Bu-t(2)-C6H3) and pentamethylcyclopentadienyl (Cp* = C5Me5) ligands was obtained for the first time. Complex 2 underwent unique Th-H addition reactions with various unsaturated compounds to afford the corresponding five-membered metallacycles, including the first example of actinide metallacyclopentyne [(Cp-Ar*)(Cp*)Th(PhCH-CC-CHPh)] (4).

Under mild conditions (25 °C, 5 mol% cat.), highly selective homo- and cross-desilacoupling of aryl and benzyl primary silanes to secondary silanes was achieved by the use of the heteroleptic barium aminobenzyl complex [(TpAd,iPr)Ba(CH2C6H4NMe2-o)] (TpAd,iPr = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate) (1) as a catalyst. Dihydrosilanes originating from catalytic redistribution and cross-desilacoupling reactions were isolated in fine yields, which demonstrates the feasible application of the barium complex in the syntheses of secondary aryl- and benzylsilanes.

Hydrogenolysis of the scorpionate-supported barium alkyl complex (Tp^Ad,iPr)Ba[CH(SiMe3)2](THF) (Tp^Ad,iPr = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate) afforded the dinuclear barium hydrido complex [(Tp^Ad,iPr)Ba(µ-H)]2 (2), which was characterized by NMR spectroscopy and single crystal X-ray analysis. Exposure of 2 with 1 atm of CO resulted in a reductive coupling process to form the cis-ethendiolate dianion (3). Reaction of 2 with one equivalent of PhCC-CCPh gave barium 1,4-diphenyl-2-butyne-1,4-diyl complex {[(Tp^Ad,iPr)Ba]2(PhCH-CC-CHPh) (4).

Treatment of the barium hydride complex [(TpAd,iPr)Ba(μ-H)]2 (TpAd,iPr = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate) (1) with an excess amount of 1,1-diphenylethylene (DPE) afforded the corresponding mono-DPE adduct [(TpAd,iPr)Ba(η6-Ph)C(Ph)Me] (2) and di-DPE adduct [(TpAd,iPr)Ba(η6-Ph)C(Ph)-CH2-C(Ph)2Me] (3), which could convert to each other through a reversible equilibrium reaction. Complex 1 catalysed DPE hydrogenation under mild conditions (30 °C, 6 atm, 5 mol% cat.).

A series of titanium and zirconium complexes with ligands based on di-isopropyl phosphorus-phenylamine and their derivatives were synthesized and characterized. These catalysts were utilized to catalyze the copolymerization of ethylene with N-acetyl-O-(dec-9-enyl)-L-tyrosine ethyl ester with high catalytic activity of 6.63 × 104 g P (mol Ti)−1 h−1 after activation by methylaluminoxane (MAO). The effects of ligand structure, metal atoms (Ti, Zr) and polymerization conditions were investigated in detail. The obtained polymers were characterized by 13C-NMR, DSC, FT-IR, and GPC. The results showed that the obtained copolymer had a high comonomer incorporation rate of 2.56 mol % within the copolymer chain. The melting temperature of the copolymer was up to 138.9 °C, higher than that of the obtained homopolyethylene.