THE SYNTHESIS AND N-H ACTIVATION OF TRINUCLEAR OSMIUM ALKYLIDENIMINE COMPLEXES. THE MOLECULAR STRUCTURE OF Os3(CO)11.

Article abstract of DOI:10.1016/S0022-328X(00)87096-5

Trinuclear osmium alkylidenimine complexes of the type Os3(CO)11(NHCR2) were synthesized by condensation of the ammonia complex Os3(CO)11(NH3) with ketones.The structure of the cyclohexylidenimine cluster Os3(CO)11- was determined by a single X-ray structure analysis.The complex crystallizes in space group <*> with a = 8.277(3), b = 11.746(4), c = 12.951(4) Angstroem, α = 98.22(2), β = 95.25(2), γ = 113.81(2)deg, and Z = 2.The structure was refined to R = 0.047 for 3596 observed diffractometer data.In the solid state the osmium atoms define an isosceles triangle with the alkylidenimine ligand in an axial position.The N atom has a planar coordination geometry and the six-membered cyclohexylidene ring adopts the chair conformation.Upon heating, the N-H bond of the alkylidene ligand in Os3(CO)11(NHCR2) is activated, and the hydrogen atom transferred to the metal frame, affording alkylidenimido clusters of the type Os3(CO)10(μ-H)(μ-NCR2).