Synthesis and Characterization of Molybdenum Carbide Clusters MonC4n, (n = 1 to 4)
Changming Jin 1,
R. E. Haufler 1,
R. L. Hettich 1,
C. M. Barshick 1,
R. N. Compton 2,
A. A. Puretzky 3,
A. V. Dem'yanenko 3, and
A. A. Tuinman 4
1 Oak Ridge National Laboratory, Oak Ridge, TN 37831-6120
2 Oak Ridge National Laboratory, Oak Ridge, TN 37831-6125, and Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600
3 Institute of Spectroscopy, Russian Academy of Sciences, Moscow, Russia
4 Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600
Laser radiation (XeCl laser, 308-nanometer wavelength) focused into a cell containing Mo(CO)6 vapor produced ultrafine particles in the extended waist of the laser beam. Negative ion mass spectrometry revealed molybdenum carbide cluster ions with a stoichiometry MonC4n (n = 1 to 4). The MonC4n– (n = 2 to 4) ions are completely unreactive with NH3, H2O, and O2, suggesting structures in which the molybdenum atoms are unavailable for coordination to additional ligands. Collision-induced dissociation studies of these anions show the loss of MoC4 units as the main fragmentation pathway. This observation, together with the lack of addition reactions, provides a basis for structures in which a planar cluster of two, three, or four molybdenum atoms is surrounded by, and bonded to, carbon dimers.
Submitted on July 6, 1993
Accepted on November 9, 1993
