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 K4 Ge9 . Their reactions towards various transition metal complexes show a large variety of reactive sites. The novel threefold phosphine-functionalized [Ge9 ] clusters [Ge9 {PRRI }3 ]- {R: Ni Pr2 ; RI : Ni Pr2 (1 a) or t Bu (2 a)} are obtained by reaction of pristine [Ge9 ]4- clusters with the respective chlorophosphines. Subsequent reactions with NHCDipp CuCl yield neutral compounds (NHCDipp Cu)[Ge9 {P(Ni Pr2 )2 }3 ] (3) and (NHCDipp Cu)[Ge9 {P(Ni Pr2 )t Bu}3 ] (4), respectively. The reaction of neutral compound 3 with Cr(CO)5 (thf) yields the first uncharged fivefold substituted [Ge9 ] cluster (NHCDipp Cu)2 [Ge9 {P(Ni Pr2 )2 }2 Cr(CO)5 ] (5) via a ligand exchange reaction at the [Ge9 ] cluster core. Compounds 3 and 5 are characterized by single crystal structure determination.