Reversible Dihydrogen Activation and Catalytic H/D Exchange with Group 10 Heterometallic Complexes**

Abstract Reaction of a hexagonal planar palladium complex featuring [PdMg 3 H ] core with 2 is reversible and leads to the formation new 4 tetrahydride species alongside an equivalent magnesium hydride co‐product [MgH]. While reversibility this process prevented isolation ], analogous [PtMg [PtZn complexes could be isolated characterised through independent syntheses. Computational analysis (DFT, AIM, NCIPlot) bonding in series heterometallic compounds (Ni–Pt; Mg Zn) suggests that these are best described as square marginal metal‐metal interactions; strength which increases slightly group 10 descended from Zn. DFT calculations support mechanism for activation involving ligand‐assisted oxidative addition Pd. These findings were exploited develop catalytic protocol H/D exchange into zinc bonds.