μ-Alkylidyne and μ-Alkylidene Complexes from a Bridging Side-on Vinylidene Sulfur-Rich Dimolybdenum Precursor

Reaction of the μ-vinylidene complexes [Mo2(η5-C5H5)2(μ-SMe)3(μ-η1:η2-CCHR)](BF4) (1; R = Tol (1a),
n-Pr (1b)) with NaBH4 produced the μ-alkylidyne derivatives [Mo2(η5-C5H5)2(μ-SMe)3(μ-CCH2R)] (2; R = Tol
(2a), n-Pr (2b)) in good yields. Upon treatment with
HBF4·Et2O 2a and 2b were readily converted into the
μ-alkylidene species [Mo2(η5-C5H5)2(μ-SMe)3(μ-η1:η2-CHCH2R)](BF4) (R = Tol (3a), n-Pr (3b)). NMR studies
on these μ-alkylidene complexes revealed α-agostic interactions.