Germa‐ closo ‐dodecaborate: An Ambident and Flexible Coordinating Ligand

By following a simple one‐pot procedure that starts with FeBr 2 and triphos [MeC(CH 2 PPh 2 ) 3 ] or the dimer [Ru 2 (μ‐Cl) 3 (triphos) 2 ]Cl in reaction with the nucleophile [Bu 3 MeN] 2 [GeB 11 H 11 ] in acetonitrile, the zwitterionic acetonitrile adducts [M(GeB 11 H 11 )(triphos)(MeCN) 2 ] [M = Fe ( 1 ), M = Ru ( 2 )] were isolated in good yield. By means of a facile η 1 (Ge) to η 3 (B–H) rearrangement, 1 and 2 can be converted into [M(GeB 11 H 11 )(triphos)] [M = Fe ( 3 ), M = Ru ( 4 )]. The nucleophilicity of the germanium cluster vertex in the iron derivative 3 is high enough to react with [Mo(CO) 5 (thf)] to give the bimetallic complex [(triphos)Fe(GeB 11 H 11 )(MoCO) 5 ] ( 5 ), which contains an ambident coordinating germaborate moiety. The new compounds have been characterized by single‐crystal X‐ray diffraction and elemental analysis. Soluble complexes were also investigated by 1 H, 11 B, and 31 P NMR spectroscopy in solution. In the case of the insoluble complex 1 , solid‐state 31 P NMR spectroscopy was carried out.