Spin density distribution in five- and six-coordinate iron(II)-porphyrin NO complexes evidenced by magnetic circular dichroism spectroscopy

被引:75
作者
Praneeth, VKK
Neese, F
Lehnert, N
机构
[1] Univ Kiel, Inst Anorgan Chem, D-24098 Kiel, Germany
[2] Max Planck Inst Bioanorgan Chem, D-45470 Mulheim, Germany
关键词
D O I
10.1021/ic050144k
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Using magnetic circular dichroism (MCD) spectroscopy together with DFT calculations, the spin density distributions in five-coordinate [Fe(TPP)(NO)] (I) and six-coordinate [Fe(TPP)(MI)(NO)] (II, MI = 1-methylimidazole) are defined. In the five-coordinate complex, a strong Fe-NO sigma bond between pi*(h) and d(z)(2) is present that leads to a large transfer of spin density from the NO ligand to Fe(II) corresponding to an electronic structure with noticeable Fe(I)-NO+ character. Consequently, the MCD spectrum is dominated by paramagnetic C-term contributions. On coordination of the sixth ligand, the spin density is pushed back from the iron toward the NO ligand, resulting in an Fe(II)-NO(radical) type of electronic structure. This is reflected by the fact that the MCD spectrum is dominated by diamagnetic contributions.
引用
收藏
页码:2570 / 2572
页数:3
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