Bonding of heme Fe-III with dioxygen: observation and characterization of an incipient bond

作者：Ferrand Lea; Soorkia Satchin; Gregoire Gilles; Broquier Michel; Soep Benoit; Shafizadeh Niloufar^*

来源：Physical Chemistry Chemical Physics, 2015, 17(39): 25693-25699.

DOI：10.1039/c5cp01585e

While ferrous heme (Fe-II) within hemoproteins binds dioxygen efficiently, it has not yet been possible to observe the analog complex with ferric heme (Fe-III). We present the first observation and characterization of the latter complex in a cooled ion trap. The bond formation enthalpy of ferric heme-O-2 has been derived from the Van't Hoff equation by means of temperature dependent measurements. The binding energy of the [heme Fe-III-O-2](+) ionic complex is rather strong as compared to that of [heme Fe-III-N-2](+), showing the formation of an incipient Fe-O bond, which is confirmed by the electronic absorption spectra of the two complexes. This first observation of the [heme Fe-III-O-2](+) complex lays the basis for the precise description of its electronic states.

• 出版日期2015
• 单位中国地震局