Synthesis, structure, and reactions of a dimeric rhodium(I) complex with bridging ?- and ?-bonded 2,5-dimethylpyrrolido ligands

Article abstract of DOI:10.1016/0022-328X(87)80290-5

Lithium 2,5-dimethylpyrrolide reacts with 2 in THF to give the novel dimeric Rh-carbonyl (1).The X-ray structure of 1 shows that two Rh(CO)2 moieties are coordinated by two bridging pyrrole rings, where each ring acts as both a ? and a ? donor.Reactions of 1 with either PPh3(2) or AsPh3 (3) proceed rapidly and produce yellow air stable compounds.The X-ray structure of 2 confirms that it is a square-planar Rh^I complex with two PPh3 groups in trans positions and the remaining positions occupied by CO and a ?-bonded pyrrolide ion.Corresponding reactions with lithium 2,5-dimethylpyrrolide and n yield products very similar to compounds 1-3.Preliminary investigations of reactions between 2 and the anions of 3,4-dimethylpyrrole and of pyrrole suggested that the products were a mixture of compounds which were not identified.