@article {2622, title = {Bis- and Mono(amidate) Complexes of Yttrium: Synthesis, Characterization, and Use as Precatalysts for the Hydroamination of Aminoalkenes}, journal = {Organometallics}, volume = {28}, number = {14}, year = {2009}, note = {ISI Document Delivery No.: 473AWTimes Cited: 11Cited Reference Count: 47Stanlake, Louisa J. E. Schafer, Laurel L.}, month = {Jul}, pages = {3990-3998}, type = {Article}, abstract = {A high-yielding synthetic route is disclosed for yttrium bis- and mono(amidate) complexes using the reaction of amide proligand and Y(N(SiMe3)(2))(3) starting materials. The structure, bonding, and solution phase characterization data for this new class of complexes are presented. The modular nature of the amidate ligand allows for easy addition of electron-withdrawing CF3 groups in the ligand backbone to tune electronic properties of the resulting precatalysts. The amidate ligands in the bis(amidate) complexes were found to be highly fluxional on the NMR time scale, while the mono(amidate) yttrium complex required heating to 110 degrees C before ligand redistribution was observed. Three bis(amidate) complexes with differing electronic properties and one mono(amidate) complex have been used as precatalysts for hydroamination using a wide range of aminoalkene substrates. Bis(amidate) complexes bearing the more electron-withdrawing amidate ligands were found to be the most active precatalysts for intramolecular alkene hydroamination.}, keywords = {ALKENES, AMIDATE COMPLEXES, ASYMMETRIC HYDROAMINATION, EARTH, GROUP-3, HYDROAMINATION, INTRAMOLECULAR, LANTHANIDE, LIGANDS, metals, OLEFINS, ORGANOLANTHANIDE-CATALYZED HYDROAMINATION}, isbn = {0276-7333}, url = {://000268176700006}, author = {Stanlake, L. J. E. and Schafer, L. L.} } @article {1481, title = {Catalyst poisoning in catalyzed imine hydrogenation: A novel zwitterionic Rh(I)/o-hydroxy-substituted imine complex}, journal = {Journal of Molecular Catalysis a-Chemical}, volume = {257}, number = {1-2}, year = {2006}, note = {ISI Document Delivery No.: 089DITimes Cited: 3Cited Reference Count: 38Marcazzan, Paolo Patrick, Brian O. James, Brian R.}, month = {Sep}, pages = {26-30}, type = {Article}, abstract = {During investigation of the homogeneous H-2-hydrogenation of the ketimine (o-HOC6H4)C(Me)=NCH2Ph catalyzed by the [Rh(COD)(PPh3)(2)]PF6 precursor in MeOH at ambient conditions, we have isolated [Rh{eta(4)-(C6H4O)C(-)(Me)=N(+)(H)CHPh}(PPh3)(2)]PF6 (3), an unusual zwitterionic Rh complex in which the imine is coordinated via the C-4 part of the o-hydroxy-arene moiety in a quinoid form; this tautomer is generated via proton transfer from the O-atom to the N-atom within the molecular, benzenoid form. Precipitation of 3 from the MeOH solution, even under H-2, causes sequestration of the Rh and complete suppression of the catalytic activity. (In a previously studied system with the corresponding, non-hydroxy-substituted ketimine, PhC(Me) = NCH2Ph, the Rh was sequestered as an inactive o-metalated species). The solid state structure of 3 is retained in CH2Cl2 solution, but in MeOH and Me2CO reversible loss of the ketimine generates the cis-[Rh(PPh3)(2)(solvent)(2)]PF6 species. (c) 2006 Elsevier B.V. All rights reserved.}, keywords = {amine, BEHAVIOR, CATALYSIS, CATIONIC RHODIUM COMPLEXES, CHEMICALS, FINE, HYDROGENATION, HYDROLYSIS, imine complex, LIGAND, LIGANDS, OLEFINS, phosphine, RHODIUM COMPLEX, SCHIFF-BASES, SELECTIVE HYDROGENATION, zwitterion}, isbn = {1381-1169}, url = {://000240860100005}, author = {Marcazzan, P. and Patrick, B. O. and James, Brian R.} } @article {440, title = {Synthesis and structure of dimeric Rh-bis(tertiary phosphine) complexes, exceptionally useful synthetic precursors}, journal = {Comptes Rendus Chimie}, volume = {5}, number = {5}, year = {2002}, note = {ISI Document Delivery No.: 617WPTimes Cited: 12Cited Reference Count: 35}, month = {May}, pages = {373-378}, type = {Article}, abstract = {Removal of the MeOH and hydrogen from the known cis, trans, cis-Rh-111-dihydrido complexes [Rh(H)(2)(PR3)(2)(MeOH)(2)]PF6 (R= Ph, p-tolyl) results in formation of the dimeric species [Rh-2(PR3)(4)][PF6](2); X-ray analysis shows the complexes to be [(Ph3P)Rh(mu-PhPPh2)](2)(PF6](2) (and the p-tolyl analogue) containing bridged eta(6)-arene moieties, while H-1 and C-13 NMR data in CD2Cl2 provide evidence for Teta(4)-coordination of the arene within the dimer. In more strongly coordinating solvents, formation of cis-{Rh(PR3)(2)(solvent)(2)}PF6 is observed, while formation of [(PR3)(2)Rh(eta(6)-toluene)]PF6 is evident in toluene solution, and this exists in equilibrium with the bis(solvent) species in the presence, for example, of acetone or MeOH. At ambient conditions, none of the arene-containing complexes effected catalytic H-2-hydrogenation of toluene.}, keywords = {arene complexes, CATIONIC RHODIUM COMPLEXES, EXCHANGE, imines, LIGANDS, METAL-COMPLEXES, OLEFINS, PHOSPHINE COMPLEXES, Rh complexes, SELECTIVE HYDROGENATION, X-ray structures}, isbn = {1631-0748}, url = {://000179384300004}, author = {Marcazzan, P. and Ezhova, M. B. and Patrick, B. O. and James, Brian R.} } @article {6997, title = {RHODIUM(I) COMPLEXES OF BETA-DIKETONATES AND RELATED LIGANDS AS HOMOGENEOUS HYDROGENATION CATALYSTS}, journal = {Journal of Molecular Catalysis}, volume = {66}, number = {3}, year = {1991}, note = {ISI Document Delivery No.: FW904Times Cited: 22Cited Reference Count: 32}, month = {Jun}, pages = {251-269}, type = {Article}, abstract = {{Rhodium(I) complexes of beta-diketonates such as bis(eta-2-ethene)[1,3-(1-phenyl)-butanedionato-O,O{\textquoteright}]rhodium(I) and related (O ... O) ligands are active catalysts for the hydrogenation of unhindered alkenes at 30-degrees-C (1 atm H-2). Substrates such as alpha-acylaminocinnamic acid are not hydrogenated under these conditions, a result that can be used as a test for homogeneity in these catalytic systems. The crystal structures of two catalysts are described: bis(eta-2 -ethene)[1,3-(1-ferrocenyl)-butanedionato-O,O{\textquoteright}] rhodium(I), orthorhombic, space group P2(1)2(1)2(1), with a = 7.8550(4)}, keywords = {DERIVATIVES, IRIDIUM(I), OLEFINS}, isbn = {0304-5102}, url = {://A1991FW90400001}, author = {Cullen, W. R. and Rettig, S. J. and Wickenheiser, E. B.} }