REACTIONS OF [IRH2(ME(2)CO)(HPZ)(PPH(3))(2)]BF4 WITH ALKYNES - SYNTHESIS OF NEW HYDRIDE VINYL IRIDIUM(III) COMPLEXES

One of the two acetone ligands in the complex [IrH2(Me(2)CO)(2)(PPh(3))(2)]BF4 (1) is displaced by pyrazole (Hpz) to give [IrH2(Me(2)CO)(Hpz)(PPh(3))(2)]BF4 (2). Treatment of 2 with methyl propiolate and acetylenedicarboxylic dimethyl ester leads to the cationic complexes [IrH(C(COOCH3)=CH2)(Hpz)(PPh(3))(2)]BF4 (3), [IrH(CH=CHCOOCH3)(Hpz)(PPh(3))(2)]BF4 (4) and [IrH(C(COOCH3)=CH(CO2CH3))(Hp)(PPh(3))(2)]BF4 (5). The molecular structure of 3 has been determined by X-ray analysis. 3 crystallizes with an acetone molecule in the lattice, in the space group P2(1)/m with a = 9.661(3) Angstrom, b = 22.903(3) Angstrom, c = 11.056(3) Angstrom and beta = 99.82(1)degrees. The coordination around the iridium atom is a distorted octahedron with the two phosphorus atoms of the triphenylphosphine ligands occupying trans positions. The equatorial plane is formed by the cu-C atom, the oxygen atom of the carbonyl group of the ester, the hydride and a nitrogen atom of the pyrazole ligand. 3 reacts with [{Rh(mu(4)-OMe)(eta(4)-1,5-COD)}(2)] to give, via a redistribution reaction, [IrH(CH=CHCOOCH3)(MeoH)(PPh(3))(2)]BF4 (6) and [{Rh(mu-pz)(eta(4)-1,5-COD)}(2)]. The methanol molecule of 6 is displaced by P(OMe)(3) and CO to yield [IrH(CH=CHCOOCH3)L(PPh(3))(2)]BF4 (L = P(OMe)(3) (7) or CO (8)). The vinyl complexes [IrH(C(CO2CH3)=CH2)(Hpz)(P(OMe)(3))(PPh(3))(2)]BF4 (9) and [IrH(C(CO2CH3)=CH2)Cl(Hpz)(PPh(3))(2)] (10) were prepared by reaction of 3 with P(OMe)(3) and Cl- respectively. Complex 10 reacts with [{Rh(mu-OMe)(eta(4)-1,5-COD)}(2)] to afford the heterobimetallic compound [H(C(CO2CH3)=CH2)(PPh(3))(2) Ir(mu-pz)(mu-Cl)Rh(eta(4)-1,5-COD)] (11).