Clusters containing face-bridging N-donor ligands

S Clusters containing face-bridging N-donor ligands 

The cluster complex [Ru3(//-H)(/i3-ampy)(CO)9] (38) (Hampy = 2-amino-6-methylpyridine) (Fig. 7) is an efficient catalyst precursor for the selective 

At room temperature, complex 40 reacts with hydrogen (1 atm), in the absence of diphenylacetylene, to give a mixture of 38, 41, Z- and -stilbene. Although a very slow catalytic hydrogenation reaction can be observed at low [Ph2C2]/[40] ratios, no reaction is observed when more diphenylacetylene is present in solution.These 

The sequential addition of a proton and a hydride to a metal complex may be considered equivalent to an oxidative addition of hydrogen. With this in mind, the cationic hydrido derivative [Ru3(//-H)(/t3-ampy)(/ -PhC=CHPh)(CO)8][BF4] (42) (Fig. 11) was made and subsequently treated with [PPN] BH4]. This latter reaction was found to lead to Z- and -stilbene and to a mixture of cluster decomposition products. However, the cluster 40 is reformed when it is sequentially treated with HBF4 and [PPN][BH4] in the presence of diphenylacetylene. Z- and -stilbene are also produced in this reaction.It should be noted that complex 42 is coor-dinatively saturated and that a vacant site is needed before its reaction with [BH4].  

That 40 and 42 contain the same number of CO ligands supports the hypothesis that the vacant sites needed for the reactions of 40 with hydrogen (at high [Ph2C2]/ [40] ratios) and of 42 with [BH4] arise from bridging to terminal transformations of the alkenyl groups in 40 and 42 instead of from CO dissociation processes. 

---

Clusters containing face-bridging N-donor ligands and phosphine ligands... 

---