Observation of a Significantly Reduced1JC-HCoupling Constant in an Agostic f-Element Complex: X-ray Crystal Structure of (ArO)Sm[(μ-OAr)(μ-Me)AlMe2]2(Ar = 2,6-i-Pr2C6H3)

Reaction of [Sm(OAr) 3 ] 2 with 4 equiv of trimethylaluminum leads to formation of the bis-trimethylaluminum adduct (ArO)Sm[(μ-OAr)(μ-Me)AlMe 2 ] 2, which exhibits very short Sm−C(bridging) distances of 2.620(5) and 2.632(5) Å. A reduced 1 J C - H coupling constant of 106 Hz and a low ν(C−H) stretch in the solution and solid-state IR spectrum are indicative of a strong agostic Sm···H−C interaction in solution.