Syntheses of Iminophosphomamido Chlorogermylenes and Their Complexation with a Rhodium(I) Complex

Three-coordinated chlorogermylenes of the type [Ph₂ P(RN)₂ ]GeCl (3: R=^t Bu; 4: R=Dip=2,6-ⁱ Pr₂ C₆ H₃ ), which bear an N,N-substituted iminophosphonamide ligand, were synthesized. The coordination behavior of 3 and 4 toward rhodium(I) complex was investigated. When 3 was treated with 1/2 of an equivalent of [RhCl(cod)]₂ (cod=1,5-cyclooctadiene), the corresponding chlorogermylene-Rh(I) complex 5 was obtained as orange crystals. In contrast, the reaction of 4 with a half equivalent of [RhCl(cod)]₂ under a CO atmosphere resulted in the formation of a five-membered germarhodacycle 7. Compounds 3, 4, 5, and 7 were characterized using NMR spectroscopies and single-crystal X-ray diffraction. Complex 5 can be employed as a catalyst for the hydrosilylation and hydroboration reactions of diphenylacetylene, thus demonstrating the utility of germylene ligands comparable to those of NHCs in the major transition metal catalytic processes.