Quasi-Three-Coordinate Iron and Cobalt Terphenoxide Complexes {AriPr8OM(-O)}₂ (AriPr8 = C₆H-2,6-(C₆H₂-2,4,6-iPr₃)₂-3,5-iPr₂; M = Fe or Co) with M(III)₂(-O)₂ Core Structures and the Peroxide Dimer of 2-Oxepinoxy Relevant to Benzene Oxidation

Author

Pei Zhao
Hao Lei
Chengbao Ni
Jingdong Guo
Saeed Kamali
James C. Fettinger
Fernande Grandjean, Missouri University of Science and TechnologyFollow
Gary J. Long, Missouri University of Science and TechnologyFollow
Shigeru Nagase
Philip P. Power

Abstract

The bis(-oxo) dimeric complexes {Ar^iPr8OM(-O)}2 (Ar^iPr8 = C6H-2,6-(C6H2-2,4,6-ⁱPr3)2-3,5-ⁱPr2; M = Fe (1), Co (2)) were prepared by oxidation of the M(I) half-sandwich complexes {Ar^iPr8M(η⁶-arene)} (arene = benzene or toluene). Iron species 1 was prepared by reacting {Ar^iPr8Fe(η⁶-benzene)} with N2O or O2, and cobalt species 2 was prepared by reacting {Ar^iPr8Co(η⁶-toluene)} with O2. Both 1 and 2 were characterized by X-ray crystallography, UV-vis spectroscopy, magnetic measurements, and, in the case of 1, Mössbauer spectroscopy. The solid-state structures of both compounds reveal unique M2(-O)2 (M = Fe (1), Co(2)) cores with formally three-coordinate metal ions. The Fe… Fe separation in 1 bears a resemblance to that in the Fe2(-O)2 diamond core proposed for the methane monooxygenase intermediate Q. The structural differences between 1 and 2 are reflected in rather differing magnetic behavior. Compound 2 is thermally unstable, and its decomposition at room temperature resulted in the oxidation of the Ar^iPr8 ligand via oxygen insertion and addition to the central aryl ring of the terphenyl ligand to produce the 5,5'-peroxy-bis[4,6-ⁱPr2-3,7-bis(2,4,6-ⁱPr3-phenyl)oxepin-2(5H)-one] (3). The structure of the oxidized terphenyl species is closely related to that of a key intermediate proposed for the oxidation of benzene.

Recommended Citation

P. Zhao and H. Lei and C. Ni and J. Guo and S. Kamali and J. C. Fettinger and F. Grandjean and G. J. Long and S. Nagase and P. P. Power, "Quasi-Three-Coordinate Iron and Cobalt Terphenoxide Complexes {AriPr8OM(-O)}₂ (AriPr8 = C₆H-2,6-(C₆H₂-2,4,6-iPr₃)₂-3,5-iPr₂; M = Fe or Co) with M(III)₂(-O)₂ Core Structures and the Peroxide Dimer of 2-Oxepinoxy Relevant to Benzene Oxidation," Inorganic Chemistry, vol. 54, no. 18, pp. 8914 - 8922, American Chemical Society (ACS), Sep 2015.

The definitive version is available at https://doi.org/10.1021/acs.inorgchem.5b00930

Department(s)

Chemistry

International Standard Serial Number (ISSN)

0020-1669

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2015 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Sep 2015