First Observation of Photoinduced Nitrosyl Linkage Isomers of Iron Nitrosyl Porphyrins

Cheng, Lin; Novozhilova, Irina V.; Kim, Christopher; Kovalevsky, Andrey; Bagley, Kimberly A.; Coppens, Philip; Richter‐Addo, George B.

doi:10.1021/ja001243u

Cited by 81 publications

(100 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The existence of these isomers is also consistent with spectroscopic investigations on model compounds. [36] The Fe III -NO conformation is predicted to be lowest in energy, in agreement with experimental results from X-ray crystallography on NP4-NO. [43] Time-resolved IR spectroscopy should allow the detection and differentiation of the three conformations due to the different peak positions of the vibrational bands and their dynamics.…”

Section: Resultssupporting

confidence: 79%

“…In their analysis of the nitroprusside ion, Boulet et al propose that isomerization from the Fe-NO minimum to the two metastable states [Fe-ON and Feh 2 (NO)] occurs via electronically excited states. [28,29] Indeed, radiation with a xenon arc lamp has been used to prepare linkage isomers in Fe II A C H T U N G T R E N N U N G (por)(NO) compounds, [36] and the metastable states in the ferric nitroprusside ion can be prepared by irradiation. [37] Since 532 nm light induces cleavage of the FeÀNO bond in Fe III NO hemoproteins, photodissociation must occur via a low-lying electronically excited state with an asymptotic energy below that for ground-state dissociation.…”

Section: Dynamic Stability Of the Minimamentioning

confidence: 99%

See 1 more Smart Citation

Ferric and Ferrous Iron in Nitroso‐Myoglobin: Computer Simulations of Stable and Metastable States and Their Infrared Spectra

Nutt

Meuwly

2007

ChemPhysChem

View full text Add to dashboard Cite

The binding of NO to iron is involved in the biological function of many heme proteins. Contrary to ligands like CO and O(2), which only bind to ferrous (Fe(II)) iron, NO binds to both ferrous and ferric (Fe(III)) iron. In a particular protein, the natural oxidation state can therefore be expected to be tailored to the required function. Herein, we present an ab initio potential-energy surface for ferric iron interacting with NO. This potential-energy surface exhibits three minima corresponding to eta(1)-NO coordination (the global minimum), eta(1)-ON coordination and eta(2) coordination. This contrasts with the potential-energy surface for Fe(II)-NO, which exhibits only two minima (the eta(2) coordination mode for Fe(II) is a transition state, not a minimum). In addition, the binding energies of NO are substantially larger for Fe(III) than for Fe(II). We have performed molecular dynamics simulations for NO bound to ferric myoglobin (Mb(III)) and compare these with results obtained for Mb(II). Over the duration of our simulations (1.5 ns), all three binding modes are found to be stable at 200 K and transiently stable at 300 K, with eventual transformation to the eta(1)-NO global-minimum conformation. We discuss the implication of these results related to studies of rebinding processes in myoglobin.

show abstract

Section: Resultssupporting

confidence: 79%

Section: Dynamic Stability Of the Minimamentioning

confidence: 99%

Ferric and Ferrous Iron in Nitroso‐Myoglobin: Computer Simulations of Stable and Metastable States and Their Infrared Spectra

Nutt

Meuwly

2007

ChemPhysChem

View full text Add to dashboard Cite

show abstract

“…Thus, there appears to be little doubt that the active mode at 1842 cm À1 pertains to the NO stretching vibration of FeÀ heme(NO) + , excluding at the same time the possible occurrence of an isonitrosyl isomer, expected to absorb at a distinctly lower wavenumber. [12] Rather, this IRMPD feature falls close to the nitrosyl absorption displayed by a model complex (FeÀ OEP(NO) + ClO 4 À , OEP= octaethylporphyrinato dianion) whose solid state structure and NO stretching frequencies have been thoroughly examined. The n NO value occurs at 1838 and 1868 cm…”

mentioning

confidence: 67%

Direct Probe of NO Vibration in the Naked Ferric Heme Nitrosyl Complex

et al. 2008

View full text Add to dashboard Cite

“…8. As such, the Franck-Condon driven progressions appear formally similar to those common in electronic excitation between states with different geometries (36)(37)(38)(39)(40)(41) Witkowski, and coworkers (42,43). This feature of the surface is included in an approximate interpolation of the behavior along each of the three OHO directions displayed in SI Appendix, Fig.…”

Section: Strong Anharmonic Coupling Inmentioning

confidence: 79%

Hidden role of intermolecular proton transfer in the anomalously diffuse vibrational spectrum of a trapped hydronium ion

Craig

Menges

Duong

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

We report the vibrational spectra of the hydronium and methylammonium ions captured in the C 3v binding pocket of the 18-crown-6 ether ionophore. Although the NH stretching bands of the CH 3 NH 3 + ion are consistent with harmonic expectations, the OH stretching bands of H 3 O + are surprisingly broad, appearing as a diffuse background absorption with little intensity modulation over 800 cm −1 with an onset ∼400 cm −1 below the harmonic prediction. This structure persists even when only a single OH group is present in the HD 2 O + isotopologue, while the OD stretching region displays a regular progression involving a soft mode at about 85 cm −1. These results are rationalized in a vibrationally adiabatic (VA) model in which the motion of the H 3 O + ion in the crown pocket is strongly coupled with its OH stretches. In this picture, H 3 O + resides in the center of the crown in the vibrational zeropoint level, while the minima in the VA potentials associated with the excited OH vibrational states are shifted away from the symmetrical configuration displayed by the ground state. Infrared excitation between these strongly H/D isotope-dependent VA potentials then accounts for most of the broadening in the OH stretching manifold. Specifically, low-frequency motions involving concerted motions of the crown scaffold and the H 3 O + ion are driven by a Franck-Condon-like mechanism. In essence, vibrational spectroscopy of these systems can be viewed from the perspective of photochemical interconversion between transient, isomeric forms of the complexes corresponding to the initial stage of intermolecular proton transfer.vibrational spectroscopy | hydrogen bonding | vibrationally adiabatic | proton transfer

show abstract

First Observation of Photoinduced Nitrosyl Linkage Isomers of Iron Nitrosyl Porphyrins

Cited by 81 publications

References 19 publications

Ferric and Ferrous Iron in Nitroso‐Myoglobin: Computer Simulations of Stable and Metastable States and Their Infrared Spectra

Ferric and Ferrous Iron in Nitroso‐Myoglobin: Computer Simulations of Stable and Metastable States and Their Infrared Spectra

Direct Probe of NO Vibration in the Naked Ferric Heme Nitrosyl Complex

Hidden role of intermolecular proton transfer in the anomalously diffuse vibrational spectrum of a trapped hydronium ion

Contact Info

Product

Resources

About