Continuous-Wave and Pulse EPR Study of the Copper(II) Complex of N-Confused Tetraphenylporphyrin: Direct Observation of a Metal-Car
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- 作者：Carlos Calle ; Arthur Schweiger ; George Mitrikas
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：March 5, 2007
- 年：2007
- 卷：46
- 期：5
- 页码：1847 - 1855
- 全文大小：728K
- 年卷期：v.46,no.5(March 5, 2007)
- ISSN：1520-510X
文摘
N-confused or inverted porphyrins, a family of porphyrin isomers that contain a confused pyrrole ring connectedthrough its 
and 
' positions in the macrocycle, exhibit unique physical and chemical properties, like, for instance,the ability to stabilize unusual oxidation states of metals due to the reactivity of the inverted pyrrole. In this Article,a combined multifrequency continuous-wave and pulse electron paramagnetic resonance (EPR) study of the copper(II) complex of N-confused tetraphenylporphyrin (TPP) is presented. By use of pulse EPR methods like ENDORand HYSCORE, the magnetic interactions between the unpaired electron of the compound and the surroundingnitrogen nuclei were revealed. Through 13C labeling of the macrocycle, a detailed study of the carbon hyperfineinteraction became possible and provided further insight into the character of the metal-carbon bond. The observedhyperfine couplings of the ligand atoms in the first coordination sphere showed the presence of a remarkablystrong 
Cu-C bond and allowed for a detailed analysis of the spin delocalization over the porphyrin macrocycle.Interestingly, it was found that the observed delocalization is approximately 11% larger than the corresponding onefor CuTPP.
and ' positions in the macrocycle, exhibit unique physical and chemical properties, like, for instance,the ability to stabilize unusual oxidation states of metals due to the reactivity of the inverted pyrrole. In this Article,a combined multifrequency continuous-wave and pulse electron paramagnetic resonance (EPR) study of the copper(II) complex of N-confused tetraphenylporphyrin (TPP) is presented. By use of pulse EPR methods like ENDORand HYSCORE, the magnetic interactions between the unpaired electron of the compound and the surroundingnitrogen nuclei were revealed. Through 13C labeling of the macrocycle, a detailed study of the carbon hyperfineinteraction became possible and provided further insight into the character of the metal-carbon bond. The observedhyperfine couplings of the ligand atoms in the first coordination sphere showed the presence of a remarkablystrong Cu-C bond and allowed for a detailed analysis of the spin delocalization over the porphyrin macrocycle.Interestingly, it was found that the observed delocalization is approximately 11% larger than the corresponding onefor CuTPP.