OXIDATIVE ADDITION OF HSNR(3) (R=PH, (N)BU) TO THE SQUARE-PLANAR IRIDIUM(I) COMPOUNDS IR(XR)(TFB)(PCY(3)) (XR=OME, OET, (OPR)-PR-I, OPH, (SPR)-PR-N) AND IR(C(2)PH)L(2)(PCY(3)) (L(2)=TFB, 2CO)

The synthesis of the compounds Ir(OR)(TFB)(PCy(3)) (R = Et (2), Pr-i ( 3), Ph (4); TFB = tetrafluorobenzobarrelene), Ir-2(CO)(6)(PCy(3))(2) ( 5), Ir((SPr)-Pr-n)(TFB)(PCy(3)) (6), [Ir(mu-(SPr)-Pr-n)(CO)(PCy(3))](2 ) (7), Ir(C(2)R)(TFB)(PCy(3)) (R = Ph (9), Cy (10), CO(2)Me (11), SiMe (3) (12)), and Ir(C(2)Ph)(CO)(2)(PCy(3)) (13) is described. The comple xes 2-4 and 6 react with HSnR'(3) in a 1:2 molar ratio to give IrH2(Sn R'(3))(TFB)(PCy(3)) (R' = Ph (14), (n)Bu (15)) and RXSnR'(3) (X = O, S ). The structure of 14 was determined by an X-ray investigation. Compo und 14 crystallizes in the space group P $$($) over bar 1 (No. 2) with a = 10.923(1) Angstrom, b = 10.943(1) Angstrom, c = 19.679(1) Angstro m, alpha = 75.076(5)degrees, beta = 77.504(5)degrees, gamma = 72.606(5 )degrees, and Z = 2. The coordination geometry around the iridium atom could be rationalized as being derived from a highly distorted octahe dron with the triphenylstannyl group and the tricyclohexylphosphine li gand occupying pseudo-trans positions (Sn-Ir-P = 129.46(3)degrees). In solution 14 and 15 are fluxional. The fluxional process, with values for Delta H-double dagger of 13.4 +/- 0.9 (14) and 12.7 +/- 0.7 (15) k cal/mol and for Delta S-double dagger of 3.0 +/- 3.0 (14) and -1.6 +/- 2.0 (15) eu, involves the relative positions of the diolefin atoms. T he alkynyl derivative 9 reacts with HSnR'(3) to afford IrH(C(2)Ph)(SnR '(3))(TFB)(PCy(3)) (R' = Ph (19), (n)Bu (20)). Under carbon monoxide a tmosphere, 19 leads to IrH(C(2)Ph)(SnPh(3))(CO)(2)(PCy(3)) (21) and te trafluorobenzobarrelene. Compound 21, and the related derivative IrH(C (2)Ph)(Sn(n)Bu(3))(CO)(2)(PCy(3)) (22) can be also obtained by oxidati ve addition of the corresponding stannanes to 13. The complexes 14, 19 , and 21 catalyze the addition of HSnPh(3) to phenylacetylene, and fro m all experiments cis-PhCH=CH(SnPh(3)) and trans-PhCH=CH(SnPh(3)) were obtained.