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One Electron Makes Differences: From Heme {FeNO} 7 to {FeNO} 8
Author(s) -
Hu Bin,
Li Jianfeng
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201505166
Subject(s) - chemistry , crystallography , covalent bond , porphyrin , bent molecular geometry , crystal structure , moiety , ligand (biochemistry) , bond length , oxidation state , heme , spin states , stereochemistry , photochemistry , inorganic chemistry , metal , biochemistry , receptor , enzyme , organic chemistry
The first X‐ray single‐crystal structure of a {FeNO} 8 porphyrin complex [Co(Cp) 2 ][Fe(TFPPBr 8 )(NO)], and the structure of the {FeNO} 7 precursor [Fe(TFPPBr 8 )(NO)] are determined at 100 K. The two complexes are also characterized by FTIR and UV/Vis spectroscopy. [Fe(TFPPBr 8 )(NO)] − shows distinct structural features in contrast to a nitrosyl iron(II) porphyrinate on the FeNO − moiety, which include a much more bent FeNO − angle (122.4(3)°), considerably longer FeNO − (1.814(4)) and NO − (1.194(5) Å) bond distances. These and the about 180 cm −1 downshift ν N‐O stretch (1540 cm −1 ) can be understood by the covalently bonding nature between the iron(II) and the NO − ligand which possesses a two‐electron‐occupied π* orbital as a result of the reduction. The overall structural features of [Fe(TFPPBr 8 )(NO)] − and [Fe(TFPPBr 8 )(NO)] suggest a low‐spin state of the iron(II) atom at 100 K.