Nitrogen atom transfer from iron (IV) nitrogen complexes
The mechanism of nitrogen atom transfer from four-coordinate tris (carbene) borate iron (IV) nitride complexes to phosphines, and phosphates has been investigated. In the absence of limiting steric effects, the rate of nitrogen atom transfer to phosphines increases with decreasing phosphine σ-basicity. This trend has been quantified by a Hammett study with para-substituted triarylphosphines, and is contrary to the expectations of an electrophilic nitrido ligand. On the basis of electronic structure calculations, a dual-nature transition state for nitrogen atom transfer is proposed, in which a key interaction involves the transfer of electron density from the nitride highest occupied molecular orbital (HOMO) to the phosphine lowest unoccupied molecular orbital (LUMO).
The mechanism of nitrogen atom transfer from four-coordinate tris (carbene) borate iron (IV) nitride complexes to phosphines, and phosphates has been investigated. In the absence of limiting steric effects, the rate of nitrogen atom transfer to phosphines increases with decreasing phosphine σ-basicity. This trend has been quantified by a Hammett study with para-substituted triarylphosphines, and is contrary to the expectations of an electrophilic nitrido ligand. On the basis of electronic structure calculations, a dual-nature transition state for nitrogen atom transfer is proposed, in which a key interaction involves the transfer of electron density from the nitride highest occupied molecular orbital (HOMO) to the phosphine lowest unoccupied molecular orbital (LUMO).
