Trichlorostannyl complexes of iridium with both P-donor and N-donor ligands: Preparation and activity as hydrogenation catalysts
作者:Gabriele Albertin、Stefano Antoniutti、Stefano Paganelli
DOI:10.1016/j.jorganchem.2009.05.019
日期:2009.9
Bis(trichlorostannyl) complex IrH(SnCl(3))(2)(PPh(3))(2) (1) was prepared by allowing the chloro-derivative IrHCl(2)(PPh(3))(3) to react with SnCl(2)center dot 2H(2)O in ethanol. Instead, treatment of phosphite complexes IrHCl(2)P(3) [P = P(OEt)(3) and PPh(OEt)(2)] with SnCl(2)center dot 2H(2)O gave stannyl derivatives IrCl(2)(SnCl(3))P(3) (2). Pyrazole-trichlorostannyl complexes IrHCl(SnCl(3))(HRpz)P(2) (3, 4) (R = H, 3-Me; P = PPh(3), PiPr(3)) were prepared by allowing chloro-derivatives IrHCl(2)(HRpz)P(2) to react with SnCl(2)center dot 2H(2)O. 1,2-Bipyridine-trichlorostannyl complexes IrHCl(SnCl(3))(bpy)P (5) (P = PPh(3), P(i)Pr(3)) were also prepared. Complexes 1-5 were characterised spectroscopically (IR, (1)H, (31)P, (119)Sn NMR) and a geometry in solution was also established. The trichlorostannyl iridium complexes were evaluated as catalyst precursors for the hydrogenation of 2-cyclohexen-1-one and cinnamaldehyde. The influence of the stannyl group, as well as the steric hindrance of both N-donor and P-donor ligands in the catalytic activity of the complexes is discussed. (C) 2009 Elsevier B.V. All rights reserved.