Electronic structure of six-coordinate iron(III) monoazaporphyrins

Kenichiro Nakamura, Akira Ikezaki, Yoshiki Ohgo, Takahisa Ikeue, Saburo Neya, Mikio Nakamura

研究成果: Article

29 引用 (Scopus)

抄録

The electronic structures of six-coordinate iron(III) octaethylmonoazaporphyrins, [Fe(MAzP)L2]± (1), have been examined by means of 1H NMR and EPR spectroscopy to reveal the effect of meso-nitrogen in the porphyrin ring. The complexes carrying axial ligands with strong field strengths such as 1-Melm, DMAP, CN-, and tBuNC adopt the low-spin state with the (dxy) 2(dxz, dyz)3 ground state in a wide temperature range where the 1H NMR and EPR spectra are taken. In contrast, the complexes with much weaker axial ligands, such as 4-CNPy and 3,5-Cl2Py, exhibit the spin transition from the mainly S = 3/2 at 298 K to the S = 1/2 with the (dxy)2(dxz, d yz)3 ground state at 4 K. Only the THF complex has maintained the S = 3/2 throughout the temperature range examined. Thus, the electronic structures of 1 resemble those of the corresponding iron(III) octaethylporphyrins, [Fe(OEP)L2] ± (2). A couple of differences have been observed, however, in the electronic structures of 1 and 2. One of the differences is the electronic ground state in low-spin bis( tBuNC) complexes. While [Fe(OEP)(tBuNC)2] + adopts the (dxz, dyz)4(d xy)1 ground state, like most of the bis(tBuNC) complexes reported previously, [Fe(MAzP)(tBuNC)2] + has shown the (dxy)2(dxz, d yz)3 ground state. Another difference is the spin state of the bis(3,5-Cl2Py) complexes. While [Fe(OEP)(3,5-Cl 2Py)2]+ has maintained the mixed S = 3/2 and 5/2 spin state from 298 to 4 K, [Fe(MAzP)(3,5-Cl2Py) 2]+ has shown the spin transition mentioned above. These differences have been ascribed to the narrower N4 cavity and the presence of lower-lying π* orbital in MAzP as compared with OEP.

元の言語English
ページ(範囲)10299-10307
ページ数9
ジャーナルInorganic Chemistry
47
発行部数22
DOI
出版物ステータスPublished - 2008 11 17

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Ground state
Electronic structure
Iron
electronic structure
iron
ground state
Paramagnetic resonance
Nuclear magnetic resonance
Ligands
Porphyrins
nuclear magnetic resonance
ligands
porphyrins
Nitrogen
Spectroscopy
field strength
Temperature
octaethylporphyrin
nitrogen
orbitals

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry

これを引用

Nakamura, K., Ikezaki, A., Ohgo, Y., Ikeue, T., Neya, S., & Nakamura, M. (2008). Electronic structure of six-coordinate iron(III) monoazaporphyrins. Inorganic Chemistry, 47(22), 10299-10307. https://doi.org/10.1021/ic800674d

Electronic structure of six-coordinate iron(III) monoazaporphyrins. / Nakamura, Kenichiro; Ikezaki, Akira; Ohgo, Yoshiki; Ikeue, Takahisa; Neya, Saburo; Nakamura, Mikio.

:: Inorganic Chemistry, 巻 47, 番号 22, 17.11.2008, p. 10299-10307.

研究成果: Article

Nakamura, K, Ikezaki, A, Ohgo, Y, Ikeue, T, Neya, S & Nakamura, M 2008, 'Electronic structure of six-coordinate iron(III) monoazaporphyrins', Inorganic Chemistry, 巻. 47, 番号 22, pp. 10299-10307. https://doi.org/10.1021/ic800674d
Nakamura K, Ikezaki A, Ohgo Y, Ikeue T, Neya S, Nakamura M. Electronic structure of six-coordinate iron(III) monoazaporphyrins. Inorganic Chemistry. 2008 11 17;47(22):10299-10307. https://doi.org/10.1021/ic800674d
Nakamura, Kenichiro ; Ikezaki, Akira ; Ohgo, Yoshiki ; Ikeue, Takahisa ; Neya, Saburo ; Nakamura, Mikio. / Electronic structure of six-coordinate iron(III) monoazaporphyrins. :: Inorganic Chemistry. 2008 ; 巻 47, 番号 22. pp. 10299-10307.
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abstract = "The electronic structures of six-coordinate iron(III) octaethylmonoazaporphyrins, [Fe(MAzP)L2]± (1), have been examined by means of 1H NMR and EPR spectroscopy to reveal the effect of meso-nitrogen in the porphyrin ring. The complexes carrying axial ligands with strong field strengths such as 1-Melm, DMAP, CN-, and tBuNC adopt the low-spin state with the (dxy) 2(dxz, dyz)3 ground state in a wide temperature range where the 1H NMR and EPR spectra are taken. In contrast, the complexes with much weaker axial ligands, such as 4-CNPy and 3,5-Cl2Py, exhibit the spin transition from the mainly S = 3/2 at 298 K to the S = 1/2 with the (dxy)2(dxz, d yz)3 ground state at 4 K. Only the THF complex has maintained the S = 3/2 throughout the temperature range examined. Thus, the electronic structures of 1 resemble those of the corresponding iron(III) octaethylporphyrins, [Fe(OEP)L2] ± (2). A couple of differences have been observed, however, in the electronic structures of 1 and 2. One of the differences is the electronic ground state in low-spin bis( tBuNC) complexes. While [Fe(OEP)(tBuNC)2] + adopts the (dxz, dyz)4(d xy)1 ground state, like most of the bis(tBuNC) complexes reported previously, [Fe(MAzP)(tBuNC)2] + has shown the (dxy)2(dxz, d yz)3 ground state. Another difference is the spin state of the bis(3,5-Cl2Py) complexes. While [Fe(OEP)(3,5-Cl 2Py)2]+ has maintained the mixed S = 3/2 and 5/2 spin state from 298 to 4 K, [Fe(MAzP)(3,5-Cl2Py) 2]+ has shown the spin transition mentioned above. These differences have been ascribed to the narrower N4 cavity and the presence of lower-lying π* orbital in MAzP as compared with OEP.",
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AU - Neya, Saburo

AU - Nakamura, Mikio

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N2 - The electronic structures of six-coordinate iron(III) octaethylmonoazaporphyrins, [Fe(MAzP)L2]± (1), have been examined by means of 1H NMR and EPR spectroscopy to reveal the effect of meso-nitrogen in the porphyrin ring. The complexes carrying axial ligands with strong field strengths such as 1-Melm, DMAP, CN-, and tBuNC adopt the low-spin state with the (dxy) 2(dxz, dyz)3 ground state in a wide temperature range where the 1H NMR and EPR spectra are taken. In contrast, the complexes with much weaker axial ligands, such as 4-CNPy and 3,5-Cl2Py, exhibit the spin transition from the mainly S = 3/2 at 298 K to the S = 1/2 with the (dxy)2(dxz, d yz)3 ground state at 4 K. Only the THF complex has maintained the S = 3/2 throughout the temperature range examined. Thus, the electronic structures of 1 resemble those of the corresponding iron(III) octaethylporphyrins, [Fe(OEP)L2] ± (2). A couple of differences have been observed, however, in the electronic structures of 1 and 2. One of the differences is the electronic ground state in low-spin bis( tBuNC) complexes. While [Fe(OEP)(tBuNC)2] + adopts the (dxz, dyz)4(d xy)1 ground state, like most of the bis(tBuNC) complexes reported previously, [Fe(MAzP)(tBuNC)2] + has shown the (dxy)2(dxz, d yz)3 ground state. Another difference is the spin state of the bis(3,5-Cl2Py) complexes. While [Fe(OEP)(3,5-Cl 2Py)2]+ has maintained the mixed S = 3/2 and 5/2 spin state from 298 to 4 K, [Fe(MAzP)(3,5-Cl2Py) 2]+ has shown the spin transition mentioned above. These differences have been ascribed to the narrower N4 cavity and the presence of lower-lying π* orbital in MAzP as compared with OEP.

AB - The electronic structures of six-coordinate iron(III) octaethylmonoazaporphyrins, [Fe(MAzP)L2]± (1), have been examined by means of 1H NMR and EPR spectroscopy to reveal the effect of meso-nitrogen in the porphyrin ring. The complexes carrying axial ligands with strong field strengths such as 1-Melm, DMAP, CN-, and tBuNC adopt the low-spin state with the (dxy) 2(dxz, dyz)3 ground state in a wide temperature range where the 1H NMR and EPR spectra are taken. In contrast, the complexes with much weaker axial ligands, such as 4-CNPy and 3,5-Cl2Py, exhibit the spin transition from the mainly S = 3/2 at 298 K to the S = 1/2 with the (dxy)2(dxz, d yz)3 ground state at 4 K. Only the THF complex has maintained the S = 3/2 throughout the temperature range examined. Thus, the electronic structures of 1 resemble those of the corresponding iron(III) octaethylporphyrins, [Fe(OEP)L2] ± (2). A couple of differences have been observed, however, in the electronic structures of 1 and 2. One of the differences is the electronic ground state in low-spin bis( tBuNC) complexes. While [Fe(OEP)(tBuNC)2] + adopts the (dxz, dyz)4(d xy)1 ground state, like most of the bis(tBuNC) complexes reported previously, [Fe(MAzP)(tBuNC)2] + has shown the (dxy)2(dxz, d yz)3 ground state. Another difference is the spin state of the bis(3,5-Cl2Py) complexes. While [Fe(OEP)(3,5-Cl 2Py)2]+ has maintained the mixed S = 3/2 and 5/2 spin state from 298 to 4 K, [Fe(MAzP)(3,5-Cl2Py) 2]+ has shown the spin transition mentioned above. These differences have been ascribed to the narrower N4 cavity and the presence of lower-lying π* orbital in MAzP as compared with OEP.

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