Transition Metal Chemistry

Transition metals occupy the central block of the periodic table, distinguished by their (n–1)d and ns valence orbitals that accommodate variable electron counts and yield multiple accessible oxidation states. This electronic flexibility underpins rich coordination chemistry: metals bind Lewis-basic ligands in geometries ranging from four-coordinate squares and tetrahedra to six-coordinate octahedra and beyond. Ligand-field and molecular-orbital theories describe how d-orbitals split and mix, accounting for observed spin states, magnetic properties and the vivid colours of d–d and charge-transfer transitions. Catalytically, transition metals drive key processes such as water splitting, CO₂ reduction, hydroformylation, C–H activation and cross-coupling, while heterogeneous metal centres facilitate syngas conversion, ammonia synthesis and fuel-cell reactions. In materials science, applications span from single-molecule magnets and metallaaromatic frameworks to metal–organic frameworks for gas storage. In bioinorganic chemistry, iron–sulfur clusters, cytochromes and corrin complexes illustrate how subtle changes in coordination environment tune redox potentials and reactivity. Continued advances in sustainable energy, fine chemical synthesis and quantum technologies highlight the global significance of transition metal chemistry.

Research from Nature Portfolio

A recent study has shown that chemical vapour modification of Fe–N–C electrocatalysts creates a monosymmetric FeN₂+N′₂ active site embedded within a highly graphitised carbon matrix. This tailored architecture suppresses proton-induced leaching and radical attack, delivering negligible loss in half-wave potential after 200 000 accelerated stress cycles and stable performance for over 248 h under operating conditions. In supramolecular chemistry, confinement by matched macrocyclic ligands has enabled the isolation of a cationic {Bi₄} rhomboid ring that sustains σ-aromatic stabilisation in a 16-electron circuit. Crystallography, magnetically induced current mapping and quantum calculations confirm a pronounced ring current, extending the concept of aromaticity into heavy-element clusters.

Transition Metal Chemistry publication trend

The graph below shows the total number of articles in transition metal chemistry across all publications each year (not limited to Nature Index journals).

Technical terms

Ligand-field splitting: Energy separation of metal d-orbitals induced by surrounding ligands, determining spin states and spectroscopic features.

Non-precious metal catalyst: An earth-abundant metal centre (for example Fe, Co or Ni) supported in a carbon or nitrogen-doped matrix for electrocatalytic reactions.

σ-aromaticity: Aromatic character arising from delocalised σ-bonding electrons in a cyclic framework, rather than π-electrons.

Gas-diffusion electrode (GDE): An electrode design facilitating efficient transport of gaseous reactants to catalyst sites under realistic operating conditions.

Supramolecular confinement: Stabilisation of a reactive species by encapsulation within a host assembly via non-covalent interactions.

References

1. Introduction to Transition Metals.
2. Interaction Study of Oxygen and Iron‐Sulfur Clusters Based on the Density Functional Theory. International Journal of Chemical Engineering (2022).
3. Monosymmetric Fe-N4 sites enabling durable proton exchange membrane fuel cell cathode by chemical vapor modification. Nature Communications (2024).
4. Supramolecular trapping of a cationic all-metal σ-aromatic {Bi4} ring. Nature Chemistry (2024).
5. Impact of Carbon Corrosion and Denitrogenation on the Deactivation of Fe–N–C Catalysts in Alkaline Media. ACS Catalysis (2024).
6. Improving the sustainability of the ruthenium-catalysed N -directed C–H arylation of arenes with aryl halides. Green Chemistry (2023).