C(sp)-H, S-H, and Sn-H Bond Activation with a Cobalt(I) Pincer Complex.

This study focuses on the stoichiometric reactions of {2,6-(PrPO)CH}Co(PMe) with terminal alkynes, thiols, and tin hydrides as part of an effort to develop catalytic, two-electron processes with cobalt. This specific Co(I) pincer complex proves to be effective for cleaving the C(sp)-H, S-H, and Sn-H bonds to give oxidative addition products with the general formula {2,6-(PrPO)CH}CoHX(PMe) (X = alkynyl, thiolate, and stannyl groups) along with the free PMe. These reactions typically reach completion when the substituents on acetylene, sulfur, and tin are electron-withdrawing groups (e.g., phenyl, pyridyl, and alkenyl groups). In contrast, alkyl-substituted acetylenes, 1-pentanethiol, and tributyltin hydride are partially converted due to the equilibria with the corresponding oxidative addition products. The Co(I) pincer complex is not a hydrothiolation catalyst but capable of catalyzing the hydrostannation of terminal alkynes with PhSnH to produce β-()-alkenylstannanes selectively.