We report on the influence of phosphanes on the catalytic activity and selectivity of colloidal, tetraoctylammonium bromide (TOAB) stabilised palladium nanoparticles (NPs) in the semi‐hydrogenation of alkynes to olefins. Full characterisation of the catalytic system (HRTEM, EDX, XPS, IR, NMR) confirmed the formation of spherical particles with a narrow size distribution (1.9±0.5 nm). The catalytic performance of the Pd NPs in the semi‐hydrogenation of 1‐octyne, 2‐octyne and phenylacetylene to the respective olefins and the influences on the selectivity was investigated. The system shows high activities and selectivities at mild conditions (0 °C and 1.0 bar H2 pressure). It was shown that generally, phosphanes lead to an increase of both the reaction rate and selectivity towards the olefin where both steric and electronic effects of the ligand play a crucial role for the catalyst performance. A moderate steric demand of the ligand with a rather weak σ‐donating ability turned out to give the highest catalytic performance.

CoAl- and Co3Al-NPs are effective catalysts for alkyne-to-alkane hydrogenation with DIBAL-H as a co-catalyst under mild conditions (2 bar H2, 30 °C).

In order to explain the different catalytic activity in hydrogenation of two new intermetallic Ni/Ga clusters, [Ga 7 ](NiCp*) 6 (1A) and [NiGa 6 ](NiCp*) 6 (1B) (Cp* = C 5 Me 5 ), investigations of structure-function relationship have been performed based on Raman and infrared (IR) spectroscopy and theoretical (density functional theory [DFT] and normal coordinate) calculations. Full interpretation of the Raman, far-IR, and mid-IR spectra of these dark colored solids has been proposed. Based on the overview of metal-Cp* complexes, all the 14 characteristic Cp* À skeletal fundamental modes have been identified. By comparison of the Ni Cp* stretching and tilting external modes (350-380 cm À1), their force constants, and bond lengths, cluster 1B exhibited slightly stronger metal-ligand bonding. Vibrations of Ga 7 and NiGa 6 cluster cores showed that the stretching wavenumbers and force constants of Ni Ga (100-350 cm À1 ) and Ga Ga (60-250 cm À1 ) bonds are higher for cluster 1B, in agreement with the shorter averaged experimental and calculated bond lengths of Ga Ga bonds (2.873 and 2823 Å for clusters 1A and 1B, respectively). Cluster hydrogenation experiments with H 2 and D 2 showed strong Ni H and N D stretching features (at 1750 and 1260 cm À1 , respectively), and at the same time, characteristic bands of self-hydrogenated Cp*H and remained nondegraded clusters have been detected. The extent of H D exchange in cluster deuteration was obtained about 1.5 times more effective with cluster 1B than cluster 1A. The stronger hydrogen or deuterium uptake by cluster 1B and the more intensive self-hydrogenation of Cp* clearly support the higher hydrogenation activity of cluster 1B compared with that of 1A.

Nanoparticles (NPs) of Pd1-xGax (x = 0.67, 0.5, 0.33), stabilized in non-aqueous colloidal solution, were obtained via an organometallic approach under mild conditions using [Pd2(dvds)3] and GaCp* as all-hydrocarbon ligated...