Addition of Ethylene or Hydrogen to a Main-Group Metal Cluster under Mild Conditions

Reaction of the tin cluster Sn-8(Ar-Me6)(4)(Ar-Me6=C6H2-2,6-(C6H3-2,4,6-Me-3)(2)) with excess ethylene or dihydrogen at 25 degrees C/1 atmosphere yielded two new clusters that incorporated ethylene or hydrogen. The reaction with ethylene yielded Sn-4(Ar-Me6)(4)(C2H2)(5) that contained five ethylene moieties bridging four aryl substituted tin atoms and one tin-tin bond. Reaction with H-2 produced a cyclic tin species of formula (Sn(H)Ar-Me6)(4), which could also be synthesized by the reaction of {(Ar-Me6)Sn(mu-Cl)}(2) with DIBAL-H. These reactions represent the first instances of direct reactions of isolable main-group clusters with ethylene or hydrogen under mild conditions. The products were characterized in the solid state by X-ray diffraction and IR spectroscopy and in solution by multinuclear NMR and UV/Vis spectroscopies. Density functional theory calculations were performed to explain the reactivity of the cluster.