Amine-boranes reactions promoted by lanthanide(II) ions.

The catalytic activity in amine-borane dehydrogenation is shown for the first time for Ln(II) species using complexes [{(Bu-CH)CH}M·L] (M = Yb, Sm, L = (DME), TMEDA). The protonation of M(II)-C bonds with HNRRBH affords amidoborane complexes [M(NRRBH)L], which under excess HNMeBH transform to [NMeBHNMeBH] derivatives, both serving as the dehydrocoupling intermediates.

Bifunctional activation of amine-boranes by the W/Pd bimetallic analogs of "frustrated Lewis pairs".

The reaction between basic [(PCP)Pd(H)] (PCP = 2,6-(CHP(-CH))CH) and acidic [LWH(CO)] (L = Cp (), Tp (); Cp = η-cyclopentadienyl, Tp = κ-hydridotris(pyrazolyl)borate) leads to the formation of bimolecular complexes [LW(CO)(μ-CO)⋯Pd(PCP)] (, ), which catalyze amine-borane (MeNHBH, BuNHBH) dehydrogenation. The combination of variable-temperature (H, P{H}, B NMR and IR) spectroscopies and computational (ωB97XD/def2-TZVP) studies reveal the formation of an η-borane complex [(PCP)Pd(MeNHBH)][LW(CO)] () in the first step, where a BH bond strongly binds palladium and an amine group is hydrogen-bonded to tungsten. The subsequent intracomplex proton transfer is the rate-determining step, followed by an almost barrierless hydride transfer.

Stereoisomerism as an Origin of Different Reactivities of Ir(III) PC(sp)P Pincer Catalysts.

Two stereoisomers of pentacoordinate iridium(III) hydridochloride with triptycene-based PC(sp)P pincer ligand (1,8-bis(diisopropylphosphino)triptycene), and , differ by the orientation of hydride ligand relative to the bridgehead ring of triptycene. According to DFT/B3PW91/def2-TZVP calculations performed, an equatorial Cl ligand can relatively easily change its position in , whereas that is not the case in . Both complexes and readily bind the sixth ligand to protect the empty coordination site.

Coordination and organometallic chemistry of relevance to the rhodium-based catalyst for ethylene hydroamination.

The RhCl(3)·3H(2)O/PPh(3)/nBu(4)PI catalytic system for the hydroamination of ethylene by aniline is shown to be thermally stable by a recycle experiment and by a kinetic profile study. The hypothesis of the reduction under catalytic conditions to a Rh(I) species is supported by the observation of a high catalytic activity for complex [RhI(PPh(3))(2)](2). New solution equilibrium studies on [RhX(PPh(3))(2)](2) (X = Cl, I) in the presence of ligands of relevance to the catalytic reaction (PPh(3), C(2)H(4), PhNH(2), X(-), and the model Et(2)NH amine) are reported.