TY - JOUR
T1 - A high-spin iron(IV)-oxo complex supported by a trigonal nonheme pyrrolide platform
AU - Bigi, Julian P.
AU - Harman, W. Hill
AU - Lassalle-Kaiser, Benedikt
AU - Robles, Damon M.
AU - Stich, Troy A.
AU - Yano, Junko
AU - Britt, R. David
AU - Chang, Christopher J.
PY - 2012/1/25
Y1 - 2012/1/25
N2 - We report the generation and characterization of a new high-spin iron(IV)-oxo complex supported by a trigonal nonheme pyrrolide platform. Oxygen-atom transfer to [(tpa Mes)Fe II] - (tpa Ar = tris(5-arylpyrrol-2-ylmethyl)amine) in acetonitrile solution affords the Fe(III)-alkoxide product [(tpa Mes2MesO)Fe III] - resulting from intramolecular C-H oxidation with no observable ferryl intermediates. In contrast, treatment of the phenyl derivative [(tpa Ph)Fe II] - with trimethylamine N-oxide in acetonitrile solution produces the iron(IV)-oxo complex [(tpa Ph)Fe IV(O)] - that has been characterized by a suite of techniques, including mass spectrometry as well as UV-vis, FTIR, Mössbauer, XAS, and parallel-mode EPR spectroscopies. Mass spectral, FTIR, and optical absorption studies provide signatures for the iron-oxo chromophore, and Mössbauer and XAS measurements establish the presence of an Fe(IV) center. Moreover, the Fe(IV)-oxo species gives parallel-mode EPR features indicative of a high-spin, S = 2 system. Preliminary reactivity studies show that the high-spin ferryl tpa Ph complex is capable of mediating intermolecular C-H oxidation as well as oxygen-atom transfer chemistry.
AB - We report the generation and characterization of a new high-spin iron(IV)-oxo complex supported by a trigonal nonheme pyrrolide platform. Oxygen-atom transfer to [(tpa Mes)Fe II] - (tpa Ar = tris(5-arylpyrrol-2-ylmethyl)amine) in acetonitrile solution affords the Fe(III)-alkoxide product [(tpa Mes2MesO)Fe III] - resulting from intramolecular C-H oxidation with no observable ferryl intermediates. In contrast, treatment of the phenyl derivative [(tpa Ph)Fe II] - with trimethylamine N-oxide in acetonitrile solution produces the iron(IV)-oxo complex [(tpa Ph)Fe IV(O)] - that has been characterized by a suite of techniques, including mass spectrometry as well as UV-vis, FTIR, Mössbauer, XAS, and parallel-mode EPR spectroscopies. Mass spectral, FTIR, and optical absorption studies provide signatures for the iron-oxo chromophore, and Mössbauer and XAS measurements establish the presence of an Fe(IV) center. Moreover, the Fe(IV)-oxo species gives parallel-mode EPR features indicative of a high-spin, S = 2 system. Preliminary reactivity studies show that the high-spin ferryl tpa Ph complex is capable of mediating intermolecular C-H oxidation as well as oxygen-atom transfer chemistry.
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U2 - 10.1021/ja207048h
DO - 10.1021/ja207048h
M3 - Article
C2 - 22214221
AN - SCOPUS:84863011881
SN - 0002-7863
VL - 134
SP - 1536
EP - 1542
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 3
ER -