meso Substituent Effects on the Geometric and Electronic Structures of High-Spin and Low-Spin Iron (III) Complexes of Mono-meso-Substituted Octaethylporphyrins

Heather Kalish, Jason E. Camp, Marcin Stȩpień, Lechoslaw Latos-Grazyński, Marilyn M. Olmstead, Alan L. Balch

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Introduction of a single meso substituent into ClFeIII(OEP) or K[(NC)2Fe(OEP)] results in significant changes in the geometric and/or spectroscopic properties of these complexes. The mono-meso-substituted iron(III) complexes ClFeIII(meso-Ph-OEP), ClFeIII(meso-n-Bu-OEP), ClFeIII(meso-MeO-OEP), ClFeIII(meso-Cl-OEP), ClFeIII(meso-NC-OEP), ClFeIII(meso-HC(O)-OEP), and ClFeIII(meso-O2N-OEP) have been isolated and characterized by their UV/vis and paramagnetically shifted 1H NMR spectra. The structures of both ClFeIII(meso-Ph-OEP) and ClFeIII(meso-NC-OEP) have been determined by X-ray crystallography. Both molecules have five-coordinate structures typical for high-spin (S = 5/2) iron(III) complexes. However, the porphyrins themselves no longer have the domed shape seen in ClFeIII(OEP), and the N4 coordination environment possesses a slight rectangular distortion. These high-spin, mono-meso-substituted iron(III) complexes display 1H NMR spectra in chloroform-d solution which indicate that the conformational changes seen in the solid-state structures are altered by normal molecular motion to produce spectra consistent with Cs molecular symmetry. In pyridine solution the high-spin six-coordinate complexes {(py)-ClFeIII(meso-R-OEP)} form. In methanol solution in the presence of excess potassium cyanide, the low-spin six-coordinate complexes K[(NC)2FeIII(meso-R-OEP)] form. The 1H NMR spectra of these show that electron-donating substituents produce an upfield relocation of the meso-proton chemical shifts. This relocation is interpreted in terms of increased contribution from the less common (dxz,dyz)4(dxy)1 ground electronic state as the meso substituent becomes more electron donating.

LanguageEnglish
Pages989-997
Number of pages9
JournalInorganic Chemistry
Volume41
Issue number4
Early online date31 Jan 2002
DOIs
Publication statusPublished - 1 Feb 2002
Externally publishedYes

Fingerprint

Electronic structure
Relocation
Iron
Nuclear magnetic resonance
electronic structure
iron
relocation
Potassium Cyanide
nuclear magnetic resonance
Electrons
X ray crystallography
Porphyrins
Chemical shift
Electronic states
Chloroform
Methanol
Protons
cyanides
chloroform
porphyrins

Cite this

Kalish, Heather ; Camp, Jason E. ; Stȩpień, Marcin ; Latos-Grazyński, Lechoslaw ; Olmstead, Marilyn M. ; Balch, Alan L. / meso Substituent Effects on the Geometric and Electronic Structures of High-Spin and Low-Spin Iron (III) Complexes of Mono-meso-Substituted Octaethylporphyrins. In: Inorganic Chemistry. 2002 ; Vol. 41, No. 4. pp. 989-997.
@article{3264c783b77048318e56ed3a527cda84,
title = "meso Substituent Effects on the Geometric and Electronic Structures of High-Spin and Low-Spin Iron (III) Complexes of Mono-meso-Substituted Octaethylporphyrins",
abstract = "Introduction of a single meso substituent into ClFeIII(OEP) or K[(NC)2Fe(OEP)] results in significant changes in the geometric and/or spectroscopic properties of these complexes. The mono-meso-substituted iron(III) complexes ClFeIII(meso-Ph-OEP), ClFeIII(meso-n-Bu-OEP), ClFeIII(meso-MeO-OEP), ClFeIII(meso-Cl-OEP), ClFeIII(meso-NC-OEP), ClFeIII(meso-HC(O)-OEP), and ClFeIII(meso-O2N-OEP) have been isolated and characterized by their UV/vis and paramagnetically shifted 1H NMR spectra. The structures of both ClFeIII(meso-Ph-OEP) and ClFeIII(meso-NC-OEP) have been determined by X-ray crystallography. Both molecules have five-coordinate structures typical for high-spin (S = 5/2) iron(III) complexes. However, the porphyrins themselves no longer have the domed shape seen in ClFeIII(OEP), and the N4 coordination environment possesses a slight rectangular distortion. These high-spin, mono-meso-substituted iron(III) complexes display 1H NMR spectra in chloroform-d solution which indicate that the conformational changes seen in the solid-state structures are altered by normal molecular motion to produce spectra consistent with Cs molecular symmetry. In pyridine solution the high-spin six-coordinate complexes {(py)-ClFeIII(meso-R-OEP)} form. In methanol solution in the presence of excess potassium cyanide, the low-spin six-coordinate complexes K[(NC)2FeIII(meso-R-OEP)] form. The 1H NMR spectra of these show that electron-donating substituents produce an upfield relocation of the meso-proton chemical shifts. This relocation is interpreted in terms of increased contribution from the less common (dxz,dyz)4(dxy)1 ground electronic state as the meso substituent becomes more electron donating.",
author = "Heather Kalish and Camp, {Jason E.} and Marcin Stȩpień and Lechoslaw Latos-Grazyński and Olmstead, {Marilyn M.} and Balch, {Alan L.}",
year = "2002",
month = "2",
day = "1",
doi = "10.1021/ic011034q",
language = "English",
volume = "41",
pages = "989--997",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "4",

}

meso Substituent Effects on the Geometric and Electronic Structures of High-Spin and Low-Spin Iron (III) Complexes of Mono-meso-Substituted Octaethylporphyrins. / Kalish, Heather; Camp, Jason E.; Stȩpień, Marcin; Latos-Grazyński, Lechoslaw; Olmstead, Marilyn M.; Balch, Alan L.

In: Inorganic Chemistry, Vol. 41, No. 4, 01.02.2002, p. 989-997.

Research output: Contribution to journalArticle

TY - JOUR

T1 - meso Substituent Effects on the Geometric and Electronic Structures of High-Spin and Low-Spin Iron (III) Complexes of Mono-meso-Substituted Octaethylporphyrins

AU - Kalish, Heather

AU - Camp, Jason E.

AU - Stȩpień, Marcin

AU - Latos-Grazyński, Lechoslaw

AU - Olmstead, Marilyn M.

AU - Balch, Alan L.

PY - 2002/2/1

Y1 - 2002/2/1

N2 - Introduction of a single meso substituent into ClFeIII(OEP) or K[(NC)2Fe(OEP)] results in significant changes in the geometric and/or spectroscopic properties of these complexes. The mono-meso-substituted iron(III) complexes ClFeIII(meso-Ph-OEP), ClFeIII(meso-n-Bu-OEP), ClFeIII(meso-MeO-OEP), ClFeIII(meso-Cl-OEP), ClFeIII(meso-NC-OEP), ClFeIII(meso-HC(O)-OEP), and ClFeIII(meso-O2N-OEP) have been isolated and characterized by their UV/vis and paramagnetically shifted 1H NMR spectra. The structures of both ClFeIII(meso-Ph-OEP) and ClFeIII(meso-NC-OEP) have been determined by X-ray crystallography. Both molecules have five-coordinate structures typical for high-spin (S = 5/2) iron(III) complexes. However, the porphyrins themselves no longer have the domed shape seen in ClFeIII(OEP), and the N4 coordination environment possesses a slight rectangular distortion. These high-spin, mono-meso-substituted iron(III) complexes display 1H NMR spectra in chloroform-d solution which indicate that the conformational changes seen in the solid-state structures are altered by normal molecular motion to produce spectra consistent with Cs molecular symmetry. In pyridine solution the high-spin six-coordinate complexes {(py)-ClFeIII(meso-R-OEP)} form. In methanol solution in the presence of excess potassium cyanide, the low-spin six-coordinate complexes K[(NC)2FeIII(meso-R-OEP)] form. The 1H NMR spectra of these show that electron-donating substituents produce an upfield relocation of the meso-proton chemical shifts. This relocation is interpreted in terms of increased contribution from the less common (dxz,dyz)4(dxy)1 ground electronic state as the meso substituent becomes more electron donating.

AB - Introduction of a single meso substituent into ClFeIII(OEP) or K[(NC)2Fe(OEP)] results in significant changes in the geometric and/or spectroscopic properties of these complexes. The mono-meso-substituted iron(III) complexes ClFeIII(meso-Ph-OEP), ClFeIII(meso-n-Bu-OEP), ClFeIII(meso-MeO-OEP), ClFeIII(meso-Cl-OEP), ClFeIII(meso-NC-OEP), ClFeIII(meso-HC(O)-OEP), and ClFeIII(meso-O2N-OEP) have been isolated and characterized by their UV/vis and paramagnetically shifted 1H NMR spectra. The structures of both ClFeIII(meso-Ph-OEP) and ClFeIII(meso-NC-OEP) have been determined by X-ray crystallography. Both molecules have five-coordinate structures typical for high-spin (S = 5/2) iron(III) complexes. However, the porphyrins themselves no longer have the domed shape seen in ClFeIII(OEP), and the N4 coordination environment possesses a slight rectangular distortion. These high-spin, mono-meso-substituted iron(III) complexes display 1H NMR spectra in chloroform-d solution which indicate that the conformational changes seen in the solid-state structures are altered by normal molecular motion to produce spectra consistent with Cs molecular symmetry. In pyridine solution the high-spin six-coordinate complexes {(py)-ClFeIII(meso-R-OEP)} form. In methanol solution in the presence of excess potassium cyanide, the low-spin six-coordinate complexes K[(NC)2FeIII(meso-R-OEP)] form. The 1H NMR spectra of these show that electron-donating substituents produce an upfield relocation of the meso-proton chemical shifts. This relocation is interpreted in terms of increased contribution from the less common (dxz,dyz)4(dxy)1 ground electronic state as the meso substituent becomes more electron donating.

UR - http://www.scopus.com/inward/record.url?scp=0037169655&partnerID=8YFLogxK

UR - http://pubs.acs.org/journal/inocaj

U2 - 10.1021/ic011034q

DO - 10.1021/ic011034q

M3 - Article

VL - 41

SP - 989

EP - 997

JO - Inorganic Chemistry

T2 - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 4

ER -