Catalytic Alkyne Semihydrogenation with Polyhydride Ni/Ga Clusters
Maximilian Muhr, Hao Liang, Lars Allmendinger, Raphael Bühler, Fabrizio E. Napoli, Dardan Ukaj, Mirza Cokoja, Christian Jandl, Samia Kahlal, Jean‐Yves Saillard, Christian Gemel, Roland A. Fischer
Abstract
Abstract The bimetallic, decanuclear Ni 3 Ga 7 ‐cluster of the formula [Ni 3 (GaTMP) 3 ( μ 2 ‐GaTMP) 3 ( μ 3 ‐GaTMP)] ( 1 , TMP=2,2,6,6‐tetramethylpiperidinyl) reacts reversibly with dihydrogen under the formation of a series of (poly‐)hydride clusters 2 . Low‐temperature 2D NMR experiments at −80 °C show that 2 consist of a mixture of a di‐ ( 2 Di ), tetra‐ ( 2 Tetra ) and hexahydride species ( 2 Hexa ). The structures of 2 Di and 2 Tetra are assessed by a combination of 2D NMR spectroscopy and DFT calculations. The cooperation of both metals is essential for the high hydrogen uptake of the cluster. Polyhydrides 2 are catalytically active in the semihydrogenation of 4‐octyne to 4‐octene with good selectivity. The example is the first of its kind and conceptually relates properties of molecular, atom‐precise transition metal/main group metal clusters to the respective solid‐state phase in catalysis.