The iridium hexachloride anion reacts with triphenylphosphin

The iridium hexachloride anion reacts with triphenylphosphine in diethylene glycol under an atmosphere of CO to give Vaska\'s compound (Compound A). Addition of excess CO produces a five-coordinate species (Compound B). Treatment of B with NaBH4 in ethanol gives Compound O (a) Draw the structures of the three complexes. (Show metal stereocentres) (b) Predict the number of CO stretching frequencies in the Infrared spectrum of each complex.

Solution

9) (a) Compound A:

        Vaska\'s complex trans-carbonylchlorobis(triphenylphosphine)iridium(I) IrCl(CO)[P(C₆H₅)₃]₂

Compound B:

Dicarbonylchlorobis(triphenylphosphine)iridium(I)

Compound C:

Dicarbonylhydridobis(triphenylphosphine)iridium(I)

(b) Number of CO stretching frequencies in the IR spectrum of each compound:

    Compound A: 1 at 1967 cm^-1

    Compound B: 2 at 1934, 1988 cm^-1                   

    Compound C: 2