The title complex, Os3(CO)6(PMe3)3(μ 3-η2,η2,η2-C 60) (3), has been prepared by decarbonylation of Os3(CO)9(μ3-η2,η 2,η2-C60) with three equivalents of Me3NO in the presence of excess PMe3 ligand. The solid-state structures of Os3(CO)7(PMe3)2(μ 3-η2,η2,η2-C 60) (2) and 3 have been determined by single-crystal X-ray diffraction studies. Compound 2 has two inequivalent equatorial phosphine ligands on adjacent osmium atoms and compound 3, with a distorted C3 symmetry, has one equivalent equatorial phosphine ligand on each osmium center. The fluxional processes of Os3(CO)8(PMe3)(μ3-η 2,η2,η2-C60) (1), 2, and 3 have been examined by variable-temperature 13C- and 31P-NMR studies. Only one isomer exists in solution and a restricted ligand rotation on each phosphine-substituted osmium center appears to occur for all three compounds, 1-3. Activation barriers for the carbonyl exchange process increase with increasing phosphine substitution, presumably, due to the steric effect of the phosphine ligands.
Bibliographical noteFunding Information:
We are grateful to the Korea Science and Engineering Foundation for financial support of this research (Project no. 1999-1-122-001-5).
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry