New Multinuclear Copper and Silver Clusters Protected by Phosphine Ligands

Inspired by the research work about coinage metal chalcogenide clusters, the synthesis and structures of a series of silver or copper chalcogenide compounds have been reported in this thesis. In addition, the photoluminescence properties of several compounds have been explored.
In the first part, the synthesis of smaller copper clusters obtained from copper thiolates and phosphine ligands is described. The solubility of copper thiolates in common solvents is low. But by the addition of phosphine ligands, copper thiolates phosphine oligomers can be dissolved. Then these species can be crystallized by layering with non-polar solvents. This kind of compound can be understood as precursors of the following larger clusters. Nine combinations have been selected to carry out luminescence measurements. It is observed that their optical properties are influenced by the size of the clusters, shape of the core, nature of the ligands, etc. A possible reason for the light emission is a ligand to metal charge transfer (LMCT), which has been discussed in literature before.
In the second part, the synthetic approach was widened from the isolation of binary to that of ternary compounds using an additional polyoxomolybdate source. ... mehrSome new compounds are successfully obtained with copper cations and polyoxomolybdate anions but others are binary copper thiolate compounds.
In the third part E(SiMe3)2 (E = S, Se) has been added to the reactions. This E(SiMe3)2 acts as a chalcogenide source yielding metal-rich copper or silver chalcogenide clusters. Finally, these thermodynamically metastable clusters are protected by phosphine ligands or/and thiolates and isolated from solutions.