Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex
Experimental and computational results for the electron-deficient porphyrin complex [Fe(NO)(TFPPBr8)] (1; TFPPBr8=2,3,7,8,12,13,17, 18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) are reported with respect to its electron-transfer behavior. Complex 1 undergoes three one-electron proces...
Guardado en:
| Autores principales: | , |
|---|---|
| Publicado: |
2011
|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09476539_v17_n28_p7868_Pellegrino http://hdl.handle.net/20.500.12110/paper_09476539_v17_n28_p7868_Pellegrino |
| Aporte de: |
| id |
paper:paper_09476539_v17_n28_p7868_Pellegrino |
|---|---|
| record_format |
dspace |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
density functional calculations iron nitric oxide porphyrins spectroelectrochemistry Cationic forms Complex 1 Computational results DFT calculation Electron-accepting Electron-deficient Electron-transfer Ferric porphyrin High spin state High-energy shifts Higher frequencies Irreversible oxidation Lower frequencies Pentafluorophenyl Porphyrin complexes Porphyrin vibration Reversible reduction Spectroelectrochemical Spectroelectrochemical measurements Time-scales Electrons Mica Nitric oxide Oxidation Porphyrins Spectroelectrochemistry Spin dynamics Reduction iron nitric oxide porphyrin article chemical model chemical structure chemistry electrochemistry oxidation reduction reaction Electrochemistry Iron Models, Chemical Molecular Structure Nitric Oxide Oxidation-Reduction Porphyrins |
| spellingShingle |
density functional calculations iron nitric oxide porphyrins spectroelectrochemistry Cationic forms Complex 1 Computational results DFT calculation Electron-accepting Electron-deficient Electron-transfer Ferric porphyrin High spin state High-energy shifts Higher frequencies Irreversible oxidation Lower frequencies Pentafluorophenyl Porphyrin complexes Porphyrin vibration Reversible reduction Spectroelectrochemical Spectroelectrochemical measurements Time-scales Electrons Mica Nitric oxide Oxidation Porphyrins Spectroelectrochemistry Spin dynamics Reduction iron nitric oxide porphyrin article chemical model chemical structure chemistry electrochemistry oxidation reduction reaction Electrochemistry Iron Models, Chemical Molecular Structure Nitric Oxide Oxidation-Reduction Porphyrins Pellegrino, Juan Doctorovich, Fabio Ariel Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex |
| topic_facet |
density functional calculations iron nitric oxide porphyrins spectroelectrochemistry Cationic forms Complex 1 Computational results DFT calculation Electron-accepting Electron-deficient Electron-transfer Ferric porphyrin High spin state High-energy shifts Higher frequencies Irreversible oxidation Lower frequencies Pentafluorophenyl Porphyrin complexes Porphyrin vibration Reversible reduction Spectroelectrochemical Spectroelectrochemical measurements Time-scales Electrons Mica Nitric oxide Oxidation Porphyrins Spectroelectrochemistry Spin dynamics Reduction iron nitric oxide porphyrin article chemical model chemical structure chemistry electrochemistry oxidation reduction reaction Electrochemistry Iron Models, Chemical Molecular Structure Nitric Oxide Oxidation-Reduction Porphyrins |
| description |
Experimental and computational results for the electron-deficient porphyrin complex [Fe(NO)(TFPPBr8)] (1; TFPPBr8=2,3,7,8,12,13,17, 18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) are reported with respect to its electron-transfer behavior. Complex 1 undergoes three one-electron processes: two reversible reductions and one irreversible oxidation. Spectroelectrochemical measurements (IR and UV/Vis/NIR spectroscopy) of 14NO- and 15NO-containing material indicate that the first reduction to 1- occurs largely on the NO ligand to produce nitroxyl anion (NO-) character, as evident from the considerable change in νNO from 1715 to around 1550 cm-1. The second reduction to 12- does not result in a further shift of νNO to lower frequencies, but to a surprising high-energy shift to 1590 cm-1. This and the notable changes of the characteristic porphyrin vibrations as well as significant changes of the UV/Vis absorptions indicate a porphyrin-centered process; DFT calculations predict the shift of νNO to higher frequencies for the intermediate- and high-spin states of 12-. The oxidation of 1 is irreversible on the voltammetry timescale, but chemically reversible in spectroelectrochemical experiments, suggesting that the cationic form dissociates to the corresponding ferric porphyrin and NO. DFT calculations support the interpretation of the experimental results. En este trabajo se estudia el comportamiento redox del complejo {FeNO}7 con sustituyentes atractores de electrones, [Fe(NO)(TFPPBr8)]=1 (TFPPBr8=2,3,7,8,12,13,17,18- octabromo-5,10,15,20-tetrakis(pentafluorofenil)porfirina) mediante experimentos de espectroelectroquímica y cálculos computacionales. El complejo 1 presenta tres procesos electroquímicos de un electrõn: dos reducciones reversibles y una oxidaciõn irreversible. El considerable cambio de νNO de 1715 cm-1 a ≈ 1550 cm-1 indica que la primera reducciõn a 1- involucra en gran medida al ligando NO. Para la segunda reducciõn a 12- se observa, sorprendentemente, un cambio de νNO a ≈ 1590 cm-1. Este pequeño corrimiento de νNO y los cambios notables de las vibraciones asociadas a modos de la porfirina, así como los cambios significativos en la banda UV/Vis de Soret, indican un proceso centrado en la porfirina; los cálculos DFT predicen el corrimiento de νNO a mayores frecuencias para los estados de spin intermedio y alto de 1 2-. En cuanto a la oxidaciõn de 1, la onda irreversible en la voltametría cíclica sugiere que la forma catiõnica 1 + se disocia dando la porfirina de hierro(III) y NO; sin embargo, en el experimento espectroelectroquímico el proceso resulta reversible, recuperándose la νNO de 1 al reducir. Los cálculos DFT apoyan la interpretaciõn de los resultados experimentales. All in a spin: IR and UV/Vis spectroelectrochemistry reveal that the oxidation and the first reduction of [Fe(NO)(TFPPBr8)] (TFPPBr8= 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) mainly affect the FeNO moiety. In the two-electron-reduced form, the added electrons appear mainly located on the porphyrin, and DFT calculations suggest an intermediate- or high-spin state (see figure). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
| author |
Pellegrino, Juan Doctorovich, Fabio Ariel |
| author_facet |
Pellegrino, Juan Doctorovich, Fabio Ariel |
| author_sort |
Pellegrino, Juan |
| title |
Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex |
| title_short |
Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex |
| title_full |
Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex |
| title_fullStr |
Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex |
| title_full_unstemmed |
Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex |
| title_sort |
spectroelectrochemical evidence for the nitrosyl redox siblings no +, no., and no- coordinated to a strongly electron-accepting feii porphyrin: dft calculations suggest the presence of high-spin states after reduction of the feii-no - complex |
| publishDate |
2011 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09476539_v17_n28_p7868_Pellegrino http://hdl.handle.net/20.500.12110/paper_09476539_v17_n28_p7868_Pellegrino |
| work_keys_str_mv |
AT pellegrinojuan spectroelectrochemicalevidenceforthenitrosylredoxsiblingsnonoandnocoordinatedtoastronglyelectronacceptingfeiiporphyrindftcalculationssuggestthepresenceofhighspinstatesafterreductionofthefeiinocomplex AT doctorovichfabioariel spectroelectrochemicalevidenceforthenitrosylredoxsiblingsnonoandnocoordinatedtoastronglyelectronacceptingfeiiporphyrindftcalculationssuggestthepresenceofhighspinstatesafterreductionofthefeiinocomplex |
| _version_ |
1768541996165627904 |
| spelling |
paper:paper_09476539_v17_n28_p7868_Pellegrino2023-06-08T15:53:57Z Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex Pellegrino, Juan Doctorovich, Fabio Ariel density functional calculations iron nitric oxide porphyrins spectroelectrochemistry Cationic forms Complex 1 Computational results DFT calculation Electron-accepting Electron-deficient Electron-transfer Ferric porphyrin High spin state High-energy shifts Higher frequencies Irreversible oxidation Lower frequencies Pentafluorophenyl Porphyrin complexes Porphyrin vibration Reversible reduction Spectroelectrochemical Spectroelectrochemical measurements Time-scales Electrons Mica Nitric oxide Oxidation Porphyrins Spectroelectrochemistry Spin dynamics Reduction iron nitric oxide porphyrin article chemical model chemical structure chemistry electrochemistry oxidation reduction reaction Electrochemistry Iron Models, Chemical Molecular Structure Nitric Oxide Oxidation-Reduction Porphyrins Experimental and computational results for the electron-deficient porphyrin complex [Fe(NO)(TFPPBr8)] (1; TFPPBr8=2,3,7,8,12,13,17, 18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) are reported with respect to its electron-transfer behavior. Complex 1 undergoes three one-electron processes: two reversible reductions and one irreversible oxidation. Spectroelectrochemical measurements (IR and UV/Vis/NIR spectroscopy) of 14NO- and 15NO-containing material indicate that the first reduction to 1- occurs largely on the NO ligand to produce nitroxyl anion (NO-) character, as evident from the considerable change in νNO from 1715 to around 1550 cm-1. The second reduction to 12- does not result in a further shift of νNO to lower frequencies, but to a surprising high-energy shift to 1590 cm-1. This and the notable changes of the characteristic porphyrin vibrations as well as significant changes of the UV/Vis absorptions indicate a porphyrin-centered process; DFT calculations predict the shift of νNO to higher frequencies for the intermediate- and high-spin states of 12-. The oxidation of 1 is irreversible on the voltammetry timescale, but chemically reversible in spectroelectrochemical experiments, suggesting that the cationic form dissociates to the corresponding ferric porphyrin and NO. DFT calculations support the interpretation of the experimental results. En este trabajo se estudia el comportamiento redox del complejo {FeNO}7 con sustituyentes atractores de electrones, [Fe(NO)(TFPPBr8)]=1 (TFPPBr8=2,3,7,8,12,13,17,18- octabromo-5,10,15,20-tetrakis(pentafluorofenil)porfirina) mediante experimentos de espectroelectroquímica y cálculos computacionales. El complejo 1 presenta tres procesos electroquímicos de un electrõn: dos reducciones reversibles y una oxidaciõn irreversible. El considerable cambio de νNO de 1715 cm-1 a ≈ 1550 cm-1 indica que la primera reducciõn a 1- involucra en gran medida al ligando NO. Para la segunda reducciõn a 12- se observa, sorprendentemente, un cambio de νNO a ≈ 1590 cm-1. Este pequeño corrimiento de νNO y los cambios notables de las vibraciones asociadas a modos de la porfirina, así como los cambios significativos en la banda UV/Vis de Soret, indican un proceso centrado en la porfirina; los cálculos DFT predicen el corrimiento de νNO a mayores frecuencias para los estados de spin intermedio y alto de 1 2-. En cuanto a la oxidaciõn de 1, la onda irreversible en la voltametría cíclica sugiere que la forma catiõnica 1 + se disocia dando la porfirina de hierro(III) y NO; sin embargo, en el experimento espectroelectroquímico el proceso resulta reversible, recuperándose la νNO de 1 al reducir. Los cálculos DFT apoyan la interpretaciõn de los resultados experimentales. All in a spin: IR and UV/Vis spectroelectrochemistry reveal that the oxidation and the first reduction of [Fe(NO)(TFPPBr8)] (TFPPBr8= 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) mainly affect the FeNO moiety. In the two-electron-reduced form, the added electrons appear mainly located on the porphyrin, and DFT calculations suggest an intermediate- or high-spin state (see figure). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Fil:Pellegrino, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Doctorovich, F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2011 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09476539_v17_n28_p7868_Pellegrino http://hdl.handle.net/20.500.12110/paper_09476539_v17_n28_p7868_Pellegrino |