Tetranuclear

Tetranuclear refers to a molecule, cluster, or complex that contains four metal centers or four nuclear cores. In inorganic and organometallic chemistry, tetranuclear clusters are discrete compounds in which four metal atoms are linked by bridging ligands and share bonding interactions that connect all centers.

Common structural motifs include tetrahedral M4 cores, cubane-like M4O4 or M4S4 units, and butterfly or other four-metal arrangements. Bridging ligands such as oxo, hydroxo, carboxylate, sulfide, cyanide and multidentate organic ligands arrange the four metals in compact networks that enable metal–metal communication and varied oxidation states.

Representative examples include Fe4S4 cubane clusters found in iron–sulfur proteins and synthetic models, tetranuclear Mn clusters related to photosynthetic water oxidation chemistry, and various Cu4, Ni4, or Mn4 cores in catalysts and magnetic materials. Tetranuclear species can be discrete molecules or motifs within larger frameworks and are often stabilized by multidentate ligands or inorganic supports.

Synthesis typically involves self-assembly from metal precursors with polydentate ligands under controlled conditions, sometimes employing templating, hydrothermal synthesis, or stepwise assembly. Characterization relies on X-ray crystallography for structure, complemented by magnetic measurements, Mössbauer spectroscopy or EPR for oxidation state information, and UV–visible spectroscopy.

Applications span catalysis, such as small-molecule activation and water oxidation models, molecular magnetism, and the study of electron-transfer processes in biological systems.

See also: metal clusters, polynuclear complexes, cubane.