TY - JOUR
T1 - Electronic ground states of low-spin iron(III) porphyrinoids
AU - Nakamura, Mikio
AU - Ohgo, Yoshiki
AU - Ikezaki, Akira
N1 - Funding Information:
This work has been supported by the Research Funds for Collaborative Project in Toho University (2007), by the Research Center for Materials with Integrated Properties (High-Tech Research Center), Toho University, and by the Grant in Aid for Scientific Research from Ministry of Education, Culture, Sports, Science and Technology, Japan. The authors thank Professors Saburo Neya of Chiba University and Masashi Takahashi of Toho University for helpful discussions. The authors also thank his current and former graduate students who have significantly contributed to the work reported from this laboratory that is referenced in this review: Takahisa Ikeue, Yumiko Kawasaki, Takashi Saitoh, Mari Fukagawa, Takanori Sakai, Nao Takahashi, Akito Hoshino, Yuya Chiba, and Hajime Eguchi.
PY - 2008/3
Y1 - 2008/3
N2 - Six-coordinate low-spin iron(III) porphyrinates adopt either common (dxy)2(dxz, dyz)3 or less common (dxz, dyz)4(dxy)1 ground state. In this review article, three major factors that affect the electronic ground state have been examined. They are (i) nature of the axial ligand, (ii) electronic effect of peripheral substituents, and (iii) deformation of porphyrin ring. On the basis of the 1H NMR, 13C NMR, and EPR data, it is now clear that (i) the axial ligands with low-lying π* orbitals such as tert-butylisocyanide and 4-cyanopyridine, (ii) the electron donating groups at the meso-carbon atoms, and (iii) the ruffled deformation of porphyrin ring stabilize the (dxz, dyz)4(dxy)1 ground state. By manipulating these factors, we are able to prepare various low-spin iron(III) porphyrinates with unusual electronic structures such as bis(imidazole) complexes with the (dxz, dyz)4(dxy)1 ground state or bis(tert-butylisocyanide) complexes with the (dxy)2(dxz, dyz)3 ground state; bis(imidazole) and bis(tert-butylisocyanide) complexes usually adopt the (dxy)2(dxz, dyz)3 and (dxz, dyz)4(dxy)1 ground state, respectively.
AB - Six-coordinate low-spin iron(III) porphyrinates adopt either common (dxy)2(dxz, dyz)3 or less common (dxz, dyz)4(dxy)1 ground state. In this review article, three major factors that affect the electronic ground state have been examined. They are (i) nature of the axial ligand, (ii) electronic effect of peripheral substituents, and (iii) deformation of porphyrin ring. On the basis of the 1H NMR, 13C NMR, and EPR data, it is now clear that (i) the axial ligands with low-lying π* orbitals such as tert-butylisocyanide and 4-cyanopyridine, (ii) the electron donating groups at the meso-carbon atoms, and (iii) the ruffled deformation of porphyrin ring stabilize the (dxz, dyz)4(dxy)1 ground state. By manipulating these factors, we are able to prepare various low-spin iron(III) porphyrinates with unusual electronic structures such as bis(imidazole) complexes with the (dxz, dyz)4(dxy)1 ground state or bis(tert-butylisocyanide) complexes with the (dxy)2(dxz, dyz)3 ground state; bis(imidazole) and bis(tert-butylisocyanide) complexes usually adopt the (dxy)2(dxz, dyz)3 and (dxz, dyz)4(dxy)1 ground state, respectively.
KW - Deformation of porphyrin ring
KW - EPR spectroscopy
KW - Electronic effects of peripheral substituents
KW - Electronic ground state axial ligands
KW - Iron(III) porphyrinoids
KW - Low-spin complexes
KW - NMR spectroscopy
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U2 - 10.1016/j.jinorgbio.2007.10.024
DO - 10.1016/j.jinorgbio.2007.10.024
M3 - Article
C2 - 18171587
AN - SCOPUS:39249083886
SN - 0162-0134
VL - 102
SP - 433
EP - 445
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
IS - 3
ER -