Reactions of BF4 with alkynes: synthesis of new hydride-vinyl iridium(III) complexes

Article abstract of DOI:10.1016/0022-328X(94)88052-2

One of the two acetone ligands in the complex BF4 (1) is displaced by pyrazole (Hpz) to give BF4 (2).Treatment of 2 with methyl propiolate and acetylenedicarboxylic dimethyl ester leads to the cationic complexes (3), (4) and (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 P2₁/m with a=9.661(3) Angstroem, b=22.903(3) Angstroem, c=11.056(3) Angstroem and β=99.82(1)^o.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 α-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 <4-1,5-COD)>2> to give, via a redistribution reaction, (6) and <4-1,5-COD)>2>.The methanol molecule of 6 is displaced by P(OMe)3 and CO to yield (L=P(OMe)3 (7) or CO (8)).The vinyl complexes BF4 (9) and (10) were prepared by reaction of 3 with P(OMe)3 and Cl^- respectively.Complex 10 reacts with <4-1,5-COD)>2> to afford the heterobimetallic compound 4-1,5-COD)> (11). Key words: Iridium; Hydride; Vinyl; Alkyne