The solution behavior of unsaturated molybdenum carbonyl species as evidenced via stereospecific carbon-13 monoxide labeling studies Academic Article uri icon

abstract

  • Stereospecific incorporation of 13CO into the triene complex, (bicyclo[6.1.0]nona-2,4,6-triene)molybdenum tricarbonyl, has been found to occur with the axially labeled 13CO tetracarbonyl derivative being formed where the triene ligand is acting as a four-electron donor. A facile, high-yield synthesis of other stereospecific 13CO-labeled cis-disubstituted derivatives of molybdenum has been developed which involves displacement of the olefin with a variety of incoming ligands, namely, nor-bornadiene, diamines, PPh3, P(OPh)3, SbPh3, and diphos. The retention of the axial 13CO label in these cis-Mo(CO)4L2 derivatives is ascribed to a site preference of these ligands(L) for an equatorial position in the square-pyramidal structure of the five-coordinate intermediates involved in this process where the barrier to CO rearrangement is large. On the other hand, when the incoming ligand is the small, relatively good π acceptor, P(OMe)3, CO rearrangement was found to readily occur. Similarly, reaction of Mo(CO)4(triene) with 13CO afforded a statistical distribution of cis and trans bis-13CO species, thus indicating that the CO groups in the [Mo(CO)s] intermediate lose their stereochemical integrity at a rate which is rapid relative to their solution lifetime. The infrared spectral details in the v(CO) region of the 13CO labeled derivatives prepared in this investigation are discussed. © 1978, American Chemical Society. All rights reserved.

author list (cited authors)

  • Darensbourg, D. J., & Salzer, A

complete list of authors

  • Darensbourg, Donald J||Salzer, Albrecht

publication date

  • January 1, 1978 11:11 AM