Synthesis and Reactivity of Multiple Phosphine-Functionalized Nonagermanide Clusters.

Herein we report on the synthesis of the first multiple phosphine-substituted nonagermanide clusters in a one-step reaction from K Ge . Their reactions towards various transition metal complexes show a large variety of reactive sites. The novel threefold phosphine-functionalized [Ge ] clusters [Ge {PRR } ] {R: N Pr ; R : N Pr (1 a) or Bu (2 a)} are obtained by reaction of pristine [Ge ] clusters with the respective chlorophosphines. Subsequent reactions with NHC CuCl yield neutral compounds (NHC Cu)[Ge {P(N Pr ) } ] (3) and (NHC Cu)[Ge {P(N Pr ) Bu} ] (4), respectively. The reaction of neutral compound 3 with Cr(CO) (thf) yields the first uncharged fivefold substituted [Ge ] cluster (NHC Cu) [Ge {P(N Pr ) } Cr(CO) ] (5) via a ligand exchange reaction at the [Ge ] cluster core. Compounds 3 and 5 are characterized by single crystal structure determination.