Tetrahedral gold(I) clusters and related coinage metal clusters stabilized by boranylethynyl ligands

• Applicant: Professor Dr. Maik Finze
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2012 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 228472253

Alkynyl complexes of the coinage metals exhibit a broad structural variety, which is decisively determined by the alkynyl ligands and expanded by weak metal∙∙∙metal bonds. We have shown that gold(I) and silver(I) complexes of carba-closo-dodecaboranylethynyl and related boranylethynyl ligands are accessible. These complexes exhibit unusually high chemical, thermal, and photochemical stabilities and they show promising photoluminescence. Dinuclear phosphane gold(I) complexes are examples for compounds that can be easily synthesized. Such complexes with sterically non-demanding phosphane ligands dimerize to give tetranuclear gold(I) clusters solely based on intermolecular aurophilic interactions. These tetranuclear gold(I) clusters are stable in the solid state and in solution, which provides the rare possibility to study intermolecular metallophilic interactions experimentally. The synthesis, photophysical characterization, and evaluation of metallophilic interactions of further gold clusters of this type with selected boranylethynyl ligands as well as clusters composed of the other coinage metals is one objective of this proposal. Silver(I) clusters and complexes with pyridine and phosphane ligands are a further example for the unusual coordination properties of the carba-closo-dodecaboranylethynyl ligand. Short metal-metal distances are indicative for strong metallophilic interactions. The silver(I) clusters exhibit unexpected room-temperature phosphorescence and one cluster shows an unprecedented phosphorescence quantum yield for this class of compounds. So, the synthesis and photophysical characterization of silver(I) as well as copper(I) complexes and clusters based on boranylethynyl and selected further ligands that are stabilized by metallophilic interactions is another objective. In continuation of our preliminary work, the study of mixed coinage metal complexes with boranylethynyl ligands is part of this study, as well.

• DFG Programme: Research Grants