Synthesis and Reactivity of Multiple Phosphine-Functionalized Nonagermanide Clusters

Area of Science:

• * Inorganic Chemistry
• * Cluster Chemistry
• * Organometallic Chemistry

Background:

• * Nonagermanide clusters ([Ge9]4-) are known precursors in cluster chemistry.
• * Functionalization of these clusters is crucial for exploring their reactivity and potential applications.
• * Previous studies have explored various substitutions, but phosphine-functionalization remains a key area for development.

Purpose of the Study:

• * To synthesize and characterize novel multi-phosphine-substituted nonagermanide clusters.
• * To investigate the reactivity of these functionalized clusters with transition metal complexes.
• * To explore the formation of unprecedented cluster architectures through ligand exchange reactions.

Main Methods:

• * One-step synthesis of phosphine-functionalized [Ge9] clusters from K4Ge9.
• * Reaction of functionalized clusters with chlorophosphines to introduce phosphine ligands.
• * Subsequent reactions with N-heterocyclic carbene copper chloride (NHCDippCuCl) and chromium carbonyl complexes.
• * Characterization of resulting compounds using single-crystal X-ray diffraction.

Main Results:

• * Successful synthesis of the first threefold phosphine-substituted [Ge9] clusters, [Ge9{PRR^I}3]-.
• * Formation of neutral compounds through reaction with NHCDippCuCl.
• * Discovery of the first uncharged fivefold substituted [Ge9] cluster, (NHCDippCu)2[Ge9{P(NiPr2)2}2Cr(CO)5], via ligand exchange.
• * Structural elucidation of key compounds 3 and 5.

Conclusions:

• * The developed method provides access to novel phosphine-functionalized nonagermanide clusters.
• * These clusters display versatile reactivity, enabling the construction of complex organometallic structures.
• * The findings expand the scope of known substituted [Ge9] clusters and highlight their potential in coordination chemistry.