Dehydrogenative Double C-H Bond Activation in a Germylene-Rhodium Complex**

Transition metal tetrylene complexes offer great opportunities for molecular cooperation due to the ambiphilic character of the group 14 element. Here we focus on the coordination of germylene [(Ar-Mes2)(2)Ge :] (Ar-Mes=C6H3-2,6-(C6H2-2,4,6-Me-3)(2)) to [RhCl(COD)](2) (COD=1,5-cyclooctadiene), which yields a neutral germyl complex in which the rhodium center exhibits both eta(6)- and eta(2)-coordination to two mesityl rings in an unusual pincer-type structure. Chloride abstraction from this species triggers a singular dehydrogenative double C-H bond activation across the Ge/Rh motif. We have isolated and fully characterized three rhodium-germyl species associated to three C-H cleavage events along this process. The reaction mechanism has been further investigated by computational means, supporting the key cooperative action of rhodium and germanium centers.

Automated summary

Transition metal tetrylene complexes show great potential for molecular cooperation, with the coordination of germylene leading to the formation of unique rhodium-germyl species and the discovery of a distinctive dehydrogenative double C-H bond activation mechanism. Computational studies support the key cooperative action of rhodium and germanium centers in this process.