Organothorium complexes

Organothorium complexes such as [Th(r 3-allyI )4] supported on dehydroxylated y-alumina have been shown to exhibit activities rivaling those of the most active platinum metal catalysts.123 Thorium maintains its original +4 oxidation states at all times that is, the mechanism does not follow the usual oxidative addition-reductive elimination pathway. Partially hydrogenated products cannot be detected... 

Kalina, D. G., Marks, T. J. Wachter, W. A. "Photochemical Synthesis of Low-Valent Organothorium Complexes. Evidence for Photoinduced B-Hydride Elimination," J. Amer. Chem. 

Scheme 8 presents a plausible mechanism for the intermolecular hydroamination of terminal alkynes promoted by the organothorium complex 1. The first step in the catalytic cycle involves the N-H a-bond activation of the primary amine by the organothorium complex yielding the bisamido-amine complex Cp2 Th(NHR )2 (H2NR ) (28) and two equivalents of methane (step 1). Complex 22 was found to be in rapid equilibrium with the corresponding bis(amido) complex 18 (step 2) [57, 60]. An additional starting point involved a similar C-H activation of the terminal alkyne with complex 1 yielding methane and the bis(acetylide) complex 17 (step 3). 

The crystal structure of the complex [Cp3U(NCMe)2] [CpThCl4 NCMe] (Rebizant et al. 1987) is unique since it contains simultaneously the well known cation complex of tbp geometry [Cp3U(NCMe)2] with, as the counter anion, an organothorium component of octahedral coordination geometry. 

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