Six-coordinate nitro complexes of iron(III) porphyrins with trans S-donor ligands. Oxo-transfer reactivity in the solid state.

Spectroscopic studies demonstrate that the 5-coordinate O-nitrito complexes Fe(Por)(eta(1)-ONO) (Por--meso-tetraphenyl- or meso-tetra-p-tolyl-porphyrinato dianions) react with the thioethers (R(2)S) dimethylsulfide and tetrahydrothiophene to give the 6-coordinate N-nitrito complexes Fe(Por)(R(2)S)(NO(2)). These reactions were conducted in low-temperature porous layered solids formed in a cryostat; however, with excess R(2)S in the atmosphere, the same species are moderately stable at room temperature. Six-coordinate O-nitrito isomers were not observed with the R(2)S proximal ligands, even though DFT calculations for the Fe(P)(DMS)(eta(1)-ONO) and Fe(P)(DMS)(NO(2)) models (P = porphinato dianion, DMS = dimethyl sulfide) show the latter to be only modestly lower energy (approximately 8 kJ/mol) than the former.