Synthesis, X-ray structure, and catalytic activity of the unusual complex [Ir(TFB)(PiPr3)2]BF4 (TFB = tetrafluorobenzobarrelene)

Complex IrCl(TFB)(PiPr(3)) (1) reacts with AgBF4 in the presence of triisopropylphosphine to afford [Ir(TFB)(PiPr(3))(2)]BF4 (2). The structure of 2 was determined by an X-ray diffraction study. The coordination geometry around the iridium center is distorted square-planar with a P-Ir-P angle of 102.7(1)degrees. Complex 2 reacts with molecular hydrogen to give cis-trans-[IrH2(TFB)(PiPr(3))(2)]BF4 (3), and with phenylacetylene to afford Ir(C2Ph)(TFB)(PiPr(3)) (4). Complex 2 is found to be a very active catalyst for the hydrogenation, of olefins and phenylacetylene. In dichloromethane as solvent at 25 degrees C and atmospheric pressure, selectivities close to 80% are achieved for the hydrogenation of the alkyne to alkene.