72895-16-0

Upstream product

• 16591-56-3 5,10,15,20-tetraphenyl porphyrin iron 
• 10102-44-0 Nitrogen dioxide 

Downstream Products

• 84152-32-9 Fe(IV)=O(tetraphenylporphinate) 
• 102494-81-5 Fe((C₆H₅)4C₂₀H₈N₄)(NO₂)2^(1-) 
• 16591-56-3 5,10,15,20-tetraphenyl porphyrin iron 

Relevant academic research and scientific papers

Reactions of nitrogen oxides with heme models. Characterization of NO and NO2 dissociation from Fe(TPP)(NO2)(NO) by flash photolysis and rapid dilution techniques: Fe(TPP)(NO2) as an unstable intermediate

Described are studies directed toward elucidating the controversial chemistry relating to the solution phase reactions of nitric oxide with the iron(II) porphyrin complex Fe(TPP)(NO) (1, TPP = mesotetraphenylporphinato2-). The only reaction observable with clean NO is the formation of the diamagnetic dinitrosyl species Fe(TPP)(NO)2 (2), and this is seen only at low temperatures (K1 -1 at ambient temperature). However, 1 does readily react reversibly with N2O3 in the presence of excess NO to give the nitro nitrosyl complex Fe(TPP)(NO2)(NO) (3), suggesting that previous claims that 1 promotes NO disproportionation to give 3 may have been compromised by traces of air in the nitric oxide sources. It is also noted that 3 undergoes reversible loss of NO to give the elusive nitro species Fe(TPP)(NO2) (4), which has been implicated as a powerful oxygen atom transfer agent in reactions with various substrates. Furthermore, in the presence of excess NO2, the latter undergoes oxidation to the stable nitrato analogue Fe(TPP)(NO3) (5). Owing to such reactivity of Fe(TPP)(NO2), flash photolysis and stopped-flow kinetics rather than static techniques were necessary for the accurate measurement of dissociation equilibria characteristic of Fe(TPP)(NO2)(NO) in 298 K toluene solution. Flash photolysis of 3 resulted in competitive NO2 and NO dissociation to give Fe(TPP)(NO) and Fe(TPP)(NO2), respectively. The rate constant for the reaction of 1 with N2O3to generate Fe(TPP)(NO2)(NO) was determined to be 1.8 × 106 M-1 s-1, and that for the NO reaction with 4 was similarly determined to be 4.2 × 105 M-1 s-1. Stopped-flow rapid dilution techniques were used to determine the rate constant for NO dissociation from 3 as 2.6 s-1. The rapid dilution experiments also demonstrated that Fe(TPP)(NO2) readily undergoes further oxidation to give Fe-(TPP)(NO3). The mechanistic implications of these observations are discussed, and it is suggested that NO2 liberated spontaneously from Fe(P)(NO2) may play a role in an important oxidative process involving this elusive species.

Spectroscopic study of the interaction between nitrogen dioxide and sublimed layers of iron(II) mesotetraphenylporphyrin

IR and electronic absorption spectroscopies with the use of isotopically substituted 15NO2 have shown that the reaction of nitrogen dioxide with sublimed layers of iron(II) mesotetraphenylporphyrin (FeTPP) has complex character and yields nitrato complex FeIIITPP · NO3-. The spectroscopic data obtained suggest that the initial stages of reaction results in structures in which NO2 is coordinated to FeTPP through the oxygen atom. Treatment of the sublimed FeTPP layers with a mixture of nitrogen oxide and dioxide result in the formation of the nitrosyl (FeTPP · NO) and nitro-nitrosyl (O2N · FeTPP · NO) complexes in the sublimed layer.