83705-82-2Relevant academic research and scientific papers
Solvento complexes of tungsten, rhenium, osmium, and iridium and the X-ray crystal structure of [IrH2(Me2CO)2(PPh3) 2]BF4
Crabtree, Robert H.,Hlatky, Gregory G.,Parnell, Charles P.,Segmüller, Brigitte E.,Uriarte, Richard J.
, p. 354 - 358 (2008/10/08)
[WH6(PMe2Ph)3], [ReH5(PMe2Ph)3], [ReH7(PPh3)2], [OsH4(PMe2Ph)3], and [IrH5(PPh3)2] react with HBF4 in MeCN (=S) to give [WH2S3(PMe2Ph)3]2+, [ReHS3(PMe2Ph)3]2+, [ReHS4(PPh3)2]2+, [OsS3(PMe2Ph)3]2+, and [IrH2S2(PPh3)2]+ as the BF4 salts. The reaction mechanism and evidence for the initial protonation of some of the d0 polyhydrides at an M-H bond is discussed. In all but the iridium case, MeOH and Me2CO failed to give analogous complexes and no alkane or alkene dehydrogenation reactions were ever observed with the acetonitrile complexes. In the iridium case a variety of solvento complexes can be obtained. Where S = Me2CO, these are active in alkene and alkane dehydrogenation, and in this case a single-crystal X-ray diffraction study was performed: monoclinic unit cell; a = 10.565 (2) ?; b = 25.315 (7) ?; c = 15.460 (4) ?; β = 95.74 (2)°; V = 4114 (4) ?3; space group P21/c; Z = 4; R = 5.6%. The trans influence of the hydride ligands on the O-bound acetone groups was pronounced: Ir-O = 2.228 (5) ? (av), ca. 10% longer than the expected 2.02 ?. This is consistent with the high reactivity of the acetone complex.
Dihydrido Olefin and Solvento Complexes of Iridium and the Mechanisms of Olefin Hydrogenation and Alkane Dehydrogenation
Crabtree, Robert H.,Demou, Peter C.,Eden, Don,Mihelcic, Jean M.,Parnell, Charles A.,et al.
, p. 6994 - 7001 (2007/10/02)
Tests for homogeneity are applied to the catalysts L2>A/CH2Cl2/H2 (cod-1,5-cyclooctadiene; A = BF4; L=PPh3, PMePh2) and their possible generality is discussed. L2>A (L=PPh3) reacts with H2 and S (S=solvent) to give the isolable complexes IrH2S2L2>A (1) in which the displacement order of the M-S groups is H2O ca.THF2L2>A (ol = C2H4, C3H8) and L2>A (ol = PhCH=CH2, C5H8, t-BuCH=CH2).Their role in hydrogenation is discussed in the light of stepwise catalytic 1H NMR studies at -80 to +25 deg C, in which they appear to be intermediates in catalysis.A catalytic cycle is proposed.Selectivity in competitive experiments is discussed.The rhodium analogues do no exhibit similar properties.
