Abstract
Peroxynitrite (-OON=O, PN) is a reactive nitrogen species (RNS) which can effect deleterious nitrative or oxidative (bio)chemistry. It may derive from reaction of superoxide anion (O2 •-) with nitric oxide (·NO) and has been suggested to form an as-yet unobserved bound heme-iron-PN intermediate in the catalytic cycle of nitric oxide dioxygenase (NOD) enzymes, which facilitate a ·NO homeostatic process, i.e., its oxidation to the nitrate anion. Here, a discrete six-coordinate low-spin porphyrinate-FeIII complex [(PIm)FeIII(-OON=O)] (3) (PIm a porphyrin moiety with a covalently tethered imidazole axial "base" donor ligand) has been identified and characterized by various spectroscopies (UV-vis, NMR, EPR, XAS, resonance Raman) and DFT calculations, following its formation at -80 °C by addition of ·NO(g) to the heme-superoxo species, [(PIm)FeIII(O2 •-)] (2). DFT calculations confirm that 3 is a six-coordinate low-spin species with the PN ligand coordinated to iron via its terminal peroxidic anionic O atom with the overall geometry being in a cis-configuration. Complex 3 thermally transforms to its isomeric low-spin nitrato form [(PIm)FeIII(NO3 -)] (4a). While previous (bio)chemical studies show that phenolic substrates undergo nitration in the presence of PN or PN-metal complexes, in the present system, addition of 2,4-di-tert-butylphenol (2,4DTBP) to complex 3 does not lead to nitrated phenol; the nitrate complex 4a still forms. DFT calculations reveal that the phenolic H atom approaches the terminal PN O atom (farthest from the metal center and ring core), effecting O-O cleavage, giving nitrogen dioxide (·NO2) plus a ferryl compound [(PIm)FeIV=O] (7); this rebounds to give [(PIm)FeIII(NO3 -)] (4a).The generation and characterization of the long sought after ferriheme peroxynitrite complex has been accomplished.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 17421-17430 |
| Number of pages | 10 |
| Journal | Journal of the American Chemical Society |
| Volume | 139 |
| Issue number | 48 |
| DOIs | |
| State | Published - Dec 6 2017 |
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ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
A Six-Coordinate Peroxynitrite Low-Spin Iron(III) Porphyrinate Complex - The Product of the Reaction of Nitrogen Monoxide (·NO(g)) with a Ferric-Superoxide Species. / Sharma, Savita K.; Schaefer, Andrew W.; Lim, Hyeongtaek; Matsumura, Hirotoshi; Moenne-Loccoz, Pierre; Hedman, Britt; Hodgson, Keith O.; Solomon, Edward I.; Karlin, Kenneth D.
In: Journal of the American Chemical Society, Vol. 139, No. 48, 06.12.2017, p. 17421-17430.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A Six-Coordinate Peroxynitrite Low-Spin Iron(III) Porphyrinate Complex - The Product of the Reaction of Nitrogen Monoxide (·NO(g)) with a Ferric-Superoxide Species
AU - Sharma, Savita K.
AU - Schaefer, Andrew W.
AU - Lim, Hyeongtaek
AU - Matsumura, Hirotoshi
AU - Moenne-Loccoz, Pierre
AU - Hedman, Britt
AU - Hodgson, Keith O.
AU - Solomon, Edward I.
AU - Karlin, Kenneth D.
PY - 2017/12/6
Y1 - 2017/12/6
N2 - Peroxynitrite (-OON=O, PN) is a reactive nitrogen species (RNS) which can effect deleterious nitrative or oxidative (bio)chemistry. It may derive from reaction of superoxide anion (O2 •-) with nitric oxide (·NO) and has been suggested to form an as-yet unobserved bound heme-iron-PN intermediate in the catalytic cycle of nitric oxide dioxygenase (NOD) enzymes, which facilitate a ·NO homeostatic process, i.e., its oxidation to the nitrate anion. Here, a discrete six-coordinate low-spin porphyrinate-FeIII complex [(PIm)FeIII(-OON=O)] (3) (PIm a porphyrin moiety with a covalently tethered imidazole axial "base" donor ligand) has been identified and characterized by various spectroscopies (UV-vis, NMR, EPR, XAS, resonance Raman) and DFT calculations, following its formation at -80 °C by addition of ·NO(g) to the heme-superoxo species, [(PIm)FeIII(O2 •-)] (2). DFT calculations confirm that 3 is a six-coordinate low-spin species with the PN ligand coordinated to iron via its terminal peroxidic anionic O atom with the overall geometry being in a cis-configuration. Complex 3 thermally transforms to its isomeric low-spin nitrato form [(PIm)FeIII(NO3 -)] (4a). While previous (bio)chemical studies show that phenolic substrates undergo nitration in the presence of PN or PN-metal complexes, in the present system, addition of 2,4-di-tert-butylphenol (2,4DTBP) to complex 3 does not lead to nitrated phenol; the nitrate complex 4a still forms. DFT calculations reveal that the phenolic H atom approaches the terminal PN O atom (farthest from the metal center and ring core), effecting O-O cleavage, giving nitrogen dioxide (·NO2) plus a ferryl compound [(PIm)FeIV=O] (7); this rebounds to give [(PIm)FeIII(NO3 -)] (4a).The generation and characterization of the long sought after ferriheme peroxynitrite complex has been accomplished.
AB - Peroxynitrite (-OON=O, PN) is a reactive nitrogen species (RNS) which can effect deleterious nitrative or oxidative (bio)chemistry. It may derive from reaction of superoxide anion (O2 •-) with nitric oxide (·NO) and has been suggested to form an as-yet unobserved bound heme-iron-PN intermediate in the catalytic cycle of nitric oxide dioxygenase (NOD) enzymes, which facilitate a ·NO homeostatic process, i.e., its oxidation to the nitrate anion. Here, a discrete six-coordinate low-spin porphyrinate-FeIII complex [(PIm)FeIII(-OON=O)] (3) (PIm a porphyrin moiety with a covalently tethered imidazole axial "base" donor ligand) has been identified and characterized by various spectroscopies (UV-vis, NMR, EPR, XAS, resonance Raman) and DFT calculations, following its formation at -80 °C by addition of ·NO(g) to the heme-superoxo species, [(PIm)FeIII(O2 •-)] (2). DFT calculations confirm that 3 is a six-coordinate low-spin species with the PN ligand coordinated to iron via its terminal peroxidic anionic O atom with the overall geometry being in a cis-configuration. Complex 3 thermally transforms to its isomeric low-spin nitrato form [(PIm)FeIII(NO3 -)] (4a). While previous (bio)chemical studies show that phenolic substrates undergo nitration in the presence of PN or PN-metal complexes, in the present system, addition of 2,4-di-tert-butylphenol (2,4DTBP) to complex 3 does not lead to nitrated phenol; the nitrate complex 4a still forms. DFT calculations reveal that the phenolic H atom approaches the terminal PN O atom (farthest from the metal center and ring core), effecting O-O cleavage, giving nitrogen dioxide (·NO2) plus a ferryl compound [(PIm)FeIV=O] (7); this rebounds to give [(PIm)FeIII(NO3 -)] (4a).The generation and characterization of the long sought after ferriheme peroxynitrite complex has been accomplished.
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UR - http://www.scopus.com/inward/citedby.url?scp=85037531563&partnerID=8YFLogxK
U2 - 10.1021/jacs.7b08468
DO - 10.1021/jacs.7b08468
M3 - Article
C2 - 29091732
AN - SCOPUS:85037531563
VL - 139
SP - 17421
EP - 17430
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 48
ER -