Homobimetallic

Homobimetallic refers to a molecular species that contains two equivalent metal centers. In such compounds, both metal atoms are the same element and typically occupy the same oxidation state. Homobimetallic compounds are contrasted with heterobimetallic compounds, which contain two different metal elements.

These compounds are common in inorganic and organometallic chemistry and include dinuclear carbonyls, arene or phosphine-bridged complexes, and metal-metal bonded clusters. A characteristic feature is the presence of a direct metal-metal bond in many examples, though some rely on bridging ligands to connect the two centers.

Typical ligands include carbonyls (CO), phosphines, and hydrides. Electron counting can often be done by considering the metal centers separately with shared ligands or by using cluster electron-counting methods.

Well-known examples of homobimetallic carbonyls are Fe2(CO)9 and Co2(CO)8; dinickel or dimolybdenum carbonyls such as Mo2(CO)10 are also cited. These compounds have served as models for metal-metal bonding and for exploring redox properties, reactivity, and catalysis in homogeneous systems.

Applications include catalysis for hydroformylation, hydrogenation, and small-molecule activation, where two identical metal sites cooperate. In research, homobimetallic complexes help elucidate principles of metal-metal bonding, electron delocalization, and dinuclear reactivity.