SYNTHESIS AND REACTIONS OF NEW HYDRIDOSILYLIRIDIUM(III) COMPLEXES CONTAINING THE DIOLEFIN TETRAFLUOROBENZOBARRELENE

Treatment of the complex [Ir(mu-OMe)(TFB)]2 (1) with acetic acid leads to the dimeric carboxylate compound [Ir(mu,eta2-O2CCH3)(TFB)]2 (2). The acetate bridges of 2 are split by monodentate ligands to give the square-planar derivatives Ir(OCOCH3)(TFB)L (L = py (3), PPh3 (4), PCY3 (5), PiPr3 (6)). The complexes 4-6 react with HSiEt3, HSiPh3, and H2SiPh2 to give the dihydride silyl complexes IrH2(SiR3') (TFB) (PR3) (R' = Et (7, 9, 11), Ph (8, 10, 12); R = Ph (7,8), Cy (9, 10), iPr (11, 12)) and IrH2(Ph2SiOCOCH3)(TFB)(PR3) (R = Ph (13), Cy (14), (i)Pr(15)). In the presence of 7, 9, and 11, phenylacetylene undergoes reaction with triethylsilane. In all experiments carried out PhCH=CH2, PhC=CSiEt3, cis-PhCH=CH(SiEt3), trans-PhCH=CH(SiEt3), and Ph(SiEt3)C=CH2 were obtained. Reactions of 7-12 with CO cause reductive elimination of HSiR3' and the formation of Ir(eta1:eta2-C12F4H7)(CO)2(PR3) (R = Ph (16), Cy (17), (i)Pr (18)). The molecular structure of 17 has been determined by X-ray investigation. 17 crystallizes with a toluene molecule in the monoclinic space group P2(1)/n with a = 10.158(3) angstrom, b = 15.075(2) angstrom, c = 21.539(7) angstrom, and beta = 92.50(2)-degrees. The coordination geometry around the iridium center can be described as a distorted trigonal bipyramid with the phosphorus atom of the phosphine ligand and the C-Ir carbon atom occupying the axial positions. The equatorial plane is defined by the two carbon monoxide ligands and by the midpoint of the double carbon-carbon bond of the carbocyclic ligand.