Synthesis, Characterization, and Reactivity of Iron Trisamidoamine Complexes That Undergo Both Metal- and Ligand-centered Oxidative Transformations

Author

Remle Çelenligil-Çetin
Patrina Paraskevopoulou
Rupam Dinda
Richard J. Staples
Ekkehard Sinn, Missouri University of Science and TechnologyFollow
Nigam P. Rath
Pericles Stavropoulos, Missouri University of Science and TechnologyFollow

Abstract

Functional systems that combine redox-active metals and noninnocent ligands are no longer rare chemical oddities; they are instead emerging as significant components of catalytic and enzymatic reactions. The present work examines the synthetic and functional aspects of iron compounds ligated by a family of new trisamidoamine ligands of the type [(RNC₆H₄) ₃N]^3- (L¹). When R is the electron-rich 4-t-Bu-Ph moiety, the ligand can undergo oxidative rearrangement and store oxidizing equivalents under specific conditions. Starting ferrous complexes of the general formula [(L¹)Fe^IIsolv]^- (solv = CH₃CN, dimethylformamide) can be easily oxidized (a) by dioxygen to afford the corresponding [(L¹)Fe^IIIOH]^- complexes, featuring several cases of terminal hydroxo units, and (b) by organochlorides (R-Cl) to provide [(L¹)Fe^IIIsolv] congeners and coupled R-R products. Efforts to synthesize [(L ¹)Fe^III-O-Fe^III(L¹)]^2- by using [Cl₃Fe^III-O-Fe^IIICl₃] ^2- indicate that intrinsic Fe^IIICl units can oxidatively rearrange the ligand to afford [(L¹ _re)(Cl)Fe ^II][Et₄N]₂, although the oxidizing equivalent is not retained. Compound [(L¹ _re)(Cl)Fe ^II][Et₄N]₂ can be further oxidized to [(L ¹ _re-2)(Cl)Fe^III][Et₄N] by CH ₂Cl₂. Finally, oxidation of [(L¹)Fe ^IIIsolv] by FeCl₃ affords [(L¹ _reH)(Cl)Fe^II(μ -Cl)₂Fe^II(Cl) (L¹ _re-2H)], which features a similar ligand rearrangement that also gives rise to a diamagnetic, doubly oxidized moiety. These results underscore the complexity of chemical transformations available to systems in which both the metal and the ligand are redox-active entities.

Recommended Citation

R. Çelenligil-Çetin et al., "Synthesis, Characterization, and Reactivity of Iron Trisamidoamine Complexes That Undergo Both Metal- and Ligand-centered Oxidative Transformations," Inorganic Chemistry, vol. 47, no. 3, pp. 1165 - 1172, American Chemical Society (ACS), Feb 2008.

The definitive version is available at https://doi.org/10.1021/ic702154z

Department(s)

Chemistry

Sponsor(s)

National Institutes of Health (U.S.)
National Science Foundation (U.S.)

Keywords and Phrases

Amine; Iron; Ligand; Metal; chemical Structure; Chemistry; Electrochemistry; Oxidation Reduction Reaction; Electrochemistry; Models, Molecular; Iron compounds

International Standard Serial Number (ISSN)

0020-1669

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2008 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Feb 2008