Carboranyl C-σ-bonded and C-functionalized carboranes as ligands in gold and silver chemistry

This report summarizes gold and silver chemistry with C-functionalized carborane ligands and also organometallic complexes with Au–Ccarboranyl σ bonds. The presence of different fragments bonded to the carbon atoms leads to ligands with different coordination preferences. Furthermore, through the partial degradation of the carborane cage the ligand charge can be modified and thus, anionic ligands are afforded. Consequently, for the synthesis of metal complexes, neutral and anionic ligands are available. These two aspects have been used to synthesise and stabilise a wide diversity of gold and silver coordination compounds. The use of carborane fragments as building blocks leads in some cases to unusual structures, clusters, rod like complexes and also to interesting properties like luminescent emissions.