NitrosylStickstoffatom

The nitrosyl nitrogen atom is the nitrogen atom that forms the nitrosyl group NO. In chemistry, NO can act as a ligand, binding to a metal center through the nitrogen atom and forming metal–nitrosyl complexes. The behavior of the nitrosyl ligand is governed by the metal’s oxidation state, the degree of back-donation from metal d orbitals into the NO π* orbitals, and the resulting geometry.

Two common binding modes are observed. In the linear mode, with the N–O–M angle close to 180 degrees, the nitrosyl ligand is often treated as NO+. This mode is associated with substantial π-backbonding from the metal to NO. In the bent mode, with smaller N–O–M angles (typically around 120–140 degrees), the ligand behaves more like neutral NO or NO−, and the electronic structure reflects different electron-counting schemes for the complex.

The nitrosyl nitrogen commonly serves as the donor site, but the ligand’s overall electronic distribution is influenced by back-donation from the metal, which can alter the N–O bond order and affect reactivity. Because NO can participate in various oxidation states within the complex, nitrosyl-bearing compounds are useful as models for studying NO transfer, storage, and release.

Applications of nitrosyl-containing species span inorganic catalysis, materials chemistry, and bioinorganic research. In biology, nitric oxide is a signaling molecule, and synthetic metal nitrosyls are explored as NO donors or probes to understand NO biology and its therapeutic potential.

In summary, the nitrosyl nitrogen atom is the N component of the NO ligand, central to the binding mode, electronic structure, and reactivity of nitrosyl-containing species in chemistry.