Synthesis, structure and reactivity of μ 3 -SnH capped trinuclear nickel cluster.

Treatment of the trichlorotin-capped trinuclear nickel cluster, [Ni 3 (dppm) 3 (μ 3 -Cl)(μ 3 -SnCl 3 )], 1, with 4 eq. NaHB(Et) 3 yields a μ 3 -SnH capped trinuclear nickel cluster, [Ni 3 (dppm) 3 (μ 3 -H)(μ 3 -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 2 (g) and generates an ethyltin-capped nickel cluster with a μ 3 -iodide, [Ni 3 (dppm) 3 (μ 3 -I)(μ 3 -Sn(CH 2 CH 3 ))], 4. Notably, insertion of alkynes into the Sn-H bond of 2 can be achieved via addition of 1 eq. 1-hexyne to generate the 1-hexen-2-yl-tin-capped nickel cluster, [Ni 3 (dppm) 3 (μ 3 H)(μ 3 -Sn(C 6 H 11 ))], 5. Addition of H 2 (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 ( E = -1.3 V, -0.8 V vs. Fc 0/+ ) and one-electron reduction process ( E = -2.7 V vs. Fc 0/+ ) observed by cyclic voltammetry.