Nickel-Phosphorus Homoleptic Carbonyl Clusters

This project is focused on the synthesis, the characterisation, and the study of the reactivity of a novel group of carbonyl clusters - nickel-phosphorus homoleptic carbonyl clusters. The interest in this couple of elements has risen because of their peculiar characteristics - in the past years nickel-phosphorus binary phases and nanoparticles have been widely used both as hydroprocessing catalysts and for their ceramic properties. In fact, by now nickel is the best transition metal to use in form of phosphide if a catalytic behaviour is expected. A further investigation on nickel-phosphorus molecular compounds could help in understanding how these materials operate. The first part of the work concerns the syntheses of new nickel-phosphorus homoleptic carbonyl clusters, and their structural and spectroscopical characterisations. Several new species will be introduced, as [Ni11P(CO)18]3-, [Ni14P2(CO)22]2-, [Ni23-xP2(CO)30-x]4- (x = 0, 1), [Ni23-xP2(CO)30-x]6- (x = 0, 1), [HNi31P4(CO)39]5-, [H2Ni31P4(CO)39]4-, [Ni29P5(PO)(CO)36]4-, [Ni39P3(CO)39]6-. The second part of the work examines the reactivity and the behaviour of the new nickel-phosphorus homoleptic carbonyl clusters. The species were tested regarding their possible redox properties, their acid-base properties, and their response towards various reactants, and the corresponding results will be reported. Eventually, a further structural analysis will be proposed, which was specifically designed for the comparison of these new nickel-phosphorus homoleptic carbonyl clusters with other heteroatomical nickel clusters, as well as with other transition metal-phosphorus clusters. The collected data will be used to draw some conclusions concerning the characteristics of this novel family of compounds, as well as their possible future applications.