Intra- vs. intermolecular configurations in the three-legged, piano-stool compounds (o, m and p-xylene)Mo(CO)3

The three (η6-xylene)Mo(CO)3 complexes have been prepared and crystallographically characterized to determine the rotational relationship of the arene ring to the undercarriage, as has been suggested by theoretical studies. In fact, no such relationship can be seen, especially when combined with eight examples of structures with Z′ > 1, where both staggered and eclipsed forms are found.