Multinuclear

Multinuclear denotes phenomena or species involving multiple nuclei. In chemistry, it most often refers to polynuclear metal complexes or clusters containing two or more metal centers connected by bridging ligands, but can also describe techniques such as multinuclear NMR spectroscopy that observe several nuclei.

Polynuclear metal complexes are organized around two or more metal centers that may be directly bonded or linked through μ-bridging ligands such as oxo, hydroxo, cyanide, sulfide, or carboxylate. The centers can be of the same element or different elements, and their proximity allows electronic communication, leading to collective redox behavior, distinctive magnetic properties, and cooperative catalysis. Nuclearity is typically established by structural characterization, most reliably by X-ray crystallography.

Synthesis and characterization: Polynuclear systems are often prepared by self-assembly of metal salts with multidentate bridging ligands or by templated strategies that direct assembly into a desired nuclearity. Characterization relies on crystallography to confirm the number and arrangement of metal centers, and on magnetic, spectroscopic, and electrochemical methods to probe electronic structure and reactivity. Multinuclear NMR spectroscopy, observing more than one type of nucleus (for example 1H, 13C, 31P), provides complementary structural and dynamic information.

Applications and examples: Multinuclear motifs appear across catalysis, coordination chemistry, and materials science. The cooperative action of adjacent metal centers enables multi-electron transformations relevant to hydrogen evolution, oxygen reduction, and hydrofunctionalization. In bioinorganic chemistry, multinuclear iron–sulfur clusters model natural enzymes. In materials chemistry, polynuclear clusters contribute to molecular magnets and cluster-based materials with tunable magnetic and electronic properties.