Organometallic Solutions: #11

11.* (1994 2 4) The following is a list of reaction classes which encompasses the majority of the transformations of organometallic compounds: (a) ligand substitution or dissociation, (b) oxidative addition, (c) reductive elimination, (d) migratory insertion, (e) electrocyclization. Now consider the catalytic cycle of reactions which are known to occur in the Monsanto acetic acid process in which methanol combines with CO to form acetic acid:

CH₃OH + CO ---(Rh catalyst, I^-)--> CH₃CO₂H

The steps in this cycle are labeled (1), (2), (3), and (4); the intermediate complexes are labeled I, II, III, and IV. Over the arrow for each step put the letter from the above list indicating the nature of that step. Under each intermediate complex put the formal oxidation state and d electron configuration of the central metal (i.e. Mo(II) d⁴). Place an asterisk beside each coordinatively unsaturated ("16-electron") complex.