Heterometallic d 8 –d 10 Coupling of Rh(I) and M(0) (M=Pd, Pt) in a Sandwich Framework of π‐Conjugated Ligands

A heterometallic M−M′ bond formation is a key to construct atomically precise bimetallic clusters and materials. However, it is sometimes not straightforward to construct a heterometallic M−M′ bond through conventional methods including redox condensation. Here, we found that a sandwich framework of π‐conjugated unsaturated hydrocarbon ligands provides a unique coordination environment that facilitates unusual coupling of d 8 Rh I and d 10 M 0 (M=Pd, Pt). The molecular orbital analysis showed that the electron‐accepting ability of the sandwich framework through back‐donation allows the formation of a dσ‐type Rh−Pd bond in a (d–d) 18 electron system.