Synthesis, structure and reactivity of μ-SnH capped trinuclear nickel cluster.

Treatment of the trichlorotin-capped trinuclear nickel cluster, [Ni(dppm)(μ-Cl)(μ-SnCl)], 1, with 4 eq. NaHB(Et) yields a μ-SnH capped trinuclear nickel cluster, [Ni(dppm)(μ-H)(μ-SnH)], 2 [dppm = bis(diphenylphosphino)methane]. Single-crystal X-ray diffraction, nuclear magnetic resonance (NMR) spectroscopy, and computational studies together support that cluster 2 is a divalent tin hydride. Complex 2 displays a wide range of reactivity including oxidative addition of bromoethane across the Sn center. Addition of 1 eq. iodoethane to complex 2 releases H (g) and generates an ethyltin-capped nickel cluster with a μ-iodide, [Ni(dppm)(μ-I)(μ-Sn(CHCH))], 4. Notably, insertion of alkynes into the Sn-H bond of 2 can be achieved addition of 1 eq. 1-hexyne to generate the 1-hexen-2-yl-tin-capped nickel cluster, [Ni(dppm)(μH)(μ-Sn(CH))], 5. Addition of H (g) to 5 regenerates the starting material, 2, and hexane. The formally 44-electron cluster 2 also displays significant redox chemistry with two reversible one-electron oxidations ( = -1.3 V, -0.8 V Fc) and one-electron reduction process ( = -2.7 V Fc) observed by cyclic voltammetry.