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 [(ArMes2)2Ge :] (ArMes=C6H3‐2,6‐(C6H2‐2,4,6‐Me3)2) to [RhCl(COD)]2 (COD=1,5‐cyclooctadiene), which yields a neutral germyl complex in which the rhodium center exhibits both η6‐ and η2‐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. [ABSTRACT FROM AUTHOR]