Isomerization of the osmium–tellurium cluster Os₃(μ-TeR)₂(CO)₁₀: a kinetic and computational study

Abstract

The kinetics for the isomerization of the 50e cluster Os3(μ-TeTol-p)2(CO)10 (), where the tellurides bridge two different Os-Os edges, to one in which the tellurides bridge the same open OsOs edge () have been measured experimentally by (1)H NMR spectroscopy. The determined activation parameters are ΔH(‡) = 77 ± 9 kJ mol(-1) and ΔS(‡) = -12 ± 28 J mol(-1) K. The conversion of to has been computationally investigated by electronic structure calculations using the model compound Os3(μ-TeMe)2(CO)10. The computed isomerization pathway is consistent with the kinetic data and the thermodynamic preference for the product stereoisomer that possesses a slipped, eclipsed conformation for the two p-tolyl groups.

Polyhedral Flexibility in the Sulfido-Capped Cluster H2Ru3(CO)9(μ3-S) on Reaction with 2-(Diphenylphosphino)thioanisole (PS) and Reversible Tripodal Rotation of the Chelated PS Ligand in H2Ru3(CO)7(κ2-PS)(μ3-S)

“…The energy ordering for different PS-chelated and PS-bridged isomers is unknown, and these data could be useful to individuals with an interest in using PS and related donors as ligand auxiliaries. Bidentate coordination of the PS donor by H 2 Ru 3 (CO) 9 (μ 3 -S) furnishes a chiral product with Ru 3 (μ 3 -S) and sulfur (MeS moiety) stereogenic centers . The latter chiral center can exhibit two distinct configurations for the Me group and the sulfur lone pair relative to the cluster polyhedron, and the resulting products are epimers .…”