Structure and Dynamics of Half-Sandwich Ruthenium(IV) Alkynyl Hydrido Complexes (original) (raw)

2 O have been structurally characterized, and their crystal structures show a transoid disposition of the hydride and alkynyl ligands. These compounds are stereochemically nonrigid and undergo a rapid equilibrium between possible stereoisomers in solution, which has been studied by variabletemperature NMR spectroscopy and computer simulation. The dynamic NMR study for these processes indicates energy barriers of ca. 11 kcal mol -1 , and moreover the differences in energy for the possible stereoisomers are very small (ca. 1 kcal mol -1 ). The alkynyl hydrido complexes rearrange to their more stable vinylidene or hydroxyvinylidene tautomers. Spontaneous dehydration of the latter leads to either vinylvinylidene or allenylidene complexes. . † Dedicated to Professor G. Jeffery Leigh, as recognition of his career and outstanding contribution to inorganic and organometallic chemistry.