Reactivity of a Fe(III)-Bound Methoxide Supported with a Tris(thiolato)phosphine Ligand: Activation of C–Cl Bond in CH2Cl2 by Nucleophilic Attack of a Fe(III)

Reactivity of a Fe(III)-Bound Methoxide Supported with a Tris(thiolato)phosphine Ligand: Activation of C–Cl Bond in CH2Cl2 by Nucleophilic Attack of a Fe(III)–OCH3 Moiety

Kai-Chun Chang†, Ching-Ju Huang†, Ya-Ho Chang†, Zong-Han Wu†, Ting-Shen Kuo∥, and Hua-Fen Hsu*†

† Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan

∥ Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan

Inorg. Chem., 2016, 55 (2), pp 566–572

DOI: 10.1021/acs.inorgchem.5b02135

Publication Date (Web): December 23, 2015

*E-mail: konopka@mail.ncku.edu.tw.

http://pubs.acs.org/doi/10.1021/acs.inorgchem.5b02135

Synopsis

A five-coordinate iron(III) methoxide complex supported by a tris(thiolato)phosphine ligand is obtained. The iron(III) center adopts a trigonal-bipyramidal geometry with the electronic structure of an intermediate-spin state (S = 2/3). The redox chemistry to access an iron(II) complex and an iron(IV) complex is also established. The iron(III)-bound methoxide demonstrates a strong nucleophilic reactivity to activate the C−Cl bond in CH2Cl2, leading to the formation of an iron(III) chloride complex that is isolated and characterized.

Abstract

Two mononuclear nonheme FeIII complexes, [PPh4][FeIII(PS3″)(OCH3)] (1) and [PPh4][FeIII(PS3″)(Cl)] (2), supported by a tris(benzenethiolato)phosphine derivative PS3″ (PS3″ = P(C6H3-3-Me3Si-2-S)33–) have been synthesized and characterized. The structures resolved from X-ray crystallography show that FeIII centers in both complexes adopt distorted trigonal-bipyramidal geometry with a methoxide or a chloride binding in the axial position. The magnetic data for both are consistent with intermediate-spin FeIII centers with a C3 symmetry (S = 3/2 ground state). The bound methoxide in 1 is labile and can be replaced by a CH3CN molecule. The forming FeIII–CH3CN species can be further reduced by cobaltcene quantitatively to a stable FeII–CH3CN complex, [Fe(PS3″)(CH3CN)]−. One-electron oxidation of 2 by ferrocenium gave a FeIVanalogue, [FeIV(PS3″)(Cl)]. Importantly, the FeIII–OCH3 moiety in complex 1 acts as a strong nucleophile that activates the C–Cl bond in CH2Cl2, leading to the formation of complex 2quantitatively. Complex 1 also reacts with other electrophiles, benzyl chloride and benzyl bromide, to generate FeIII–X species (X = Cl or Br). The reactions were investigated and monitored by UV–vis–NIR, NMR, and ESI-MS spectroscopies.

Electrochemical evidence that pyranopterin redox chemistry controls the catalysis of YedY, a mononuclear Mo enzyme

Hope Adamson a, Alexandr N. Simonov b, Michelina Kierzek c, Richard A. Rothery c, Joel H. Weiner c, Alan M. Bond b, and Alison Parkin a,1 a Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom; b School of Chemistry, Monash University, Clayton, VIC 3800, Australia; and c Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada Edited by Harry B. Gray, California Institute of Technology, Pasadena, CA, and approved October 13, 2015 (received for review August 25, 2015) http://www.pnas.org/content/112/47/14506.short A long-standing contradiction in the field of mononuclear Mo enzyme research is that small-molecule chemistry on active-site mimic compounds predicts ligand participation in the electron transfer reactions, but biochemical measurements only suggest metal-centered catalytic electron transfer.With the simultaneous measurement of substrate turnover and reversible electron transfer that is provided by Fourier-...

Rhenium(V)–oxo corrolazines: isolating redox-active ligand reactivity

Jan Paulo T. Zaragoza,a Maxime A. Sieglera and David P. Goldberg* Chem. Commun., 2015, Advance Article DOI: 10.1039/C5CC07956J Received 22 Sep 2015, Accepted 15 Oct 2015 First published online 28 Oct 2015 http://pubs.rsc.org/en/content/articlelanding/2015/cc/c5cc07956j#!divAbstract Abstract The synthesis of the first example of a third-row metallocorrolazine characterized by single crystal X-ray diffraction is reported. This ReV(O) porphyrinoid complex shows an exclusively ligand-based reactivity with strong acids and oxidizing agents. The one-electron oxidized π-radical-cation complex is capable of H-atom abstraction.

Tuning Reactivity and Selectivity in Hydrogen Atom Transfer from Aliphatic C–H Bonds to Alkoxyl Radicals: Role of Structural and Medium Effects

Michela Salamone and Massimo Bietti* Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, Italy Acc. Chem. Res., Article ASAP DOI: 10.1021/acs.accounts.5b00348 Publication Date (Web): November 6, 2015 クメンパーオキシドを光で開裂させることにより、生成するクミルアルコキシルラジカルによるアルカンやアミンのC–H切断の速度定数などの情報がまとまっています。溶媒や、酸、基質の形が反応速度定数に与える影響を定量的に評価しています。酸化反応をしている方は、手元に置いておいても良いのでしょうか。

C–H Bond Oxidation Catalyzed by an Imine-Based Iron Complex: A Mechanistic Insight

Giorgio Olivo§¶, Martina Nardi§, Diego Vìdal¶, Alessia Barbieri§, Andrea Lapi§‡, Laura Gómez¶⊥, Osvaldo Lanzalunga§‡, Miquel Costas*¶, and Stefano Di Stefano*§‡ § Università degli Studi di Roma, Rome, Italy ¶ Institut de Química Computacional i Catàlisi (IQCC), Girona, Spain Inorg. Chem., 2015, 54 (21), pp 10141–10152 DOI: 10.1021/acs.inorgchem.5b01500 Publication Date (Web): October 12, 2015 A family of imine-based nonheme iron(II) complexes (LX)2Fe(OTf)2 has been prepared, characterized, and employed as C–H oxidation catalysts. Ligands LX (X = 1, 2, 3, and 4) stand for tridentate imine ligands resulting from spontaneous condensation of 2-pycolyl-amine and 4-substituted-2-picolyl aldehydes. Fast and quantitative formation of the complex occurs just upon mixing aldehyde, amine, and Fe(OTf)2 in a 2:2:1 ratio in acetonitrile solution. The solid-state structures of (L1)2Fe(OTf)(ClO4) and (L3)2Fe(OTf)2 are reported, showing a low-spin octahedral iron center, with the lig...

Oxidative Alkene Cleavage Catalysed by Manganese-Dependent Cupin TM1459 from Thermotoga maritima

van Hajnal 1 , Kurt Faber 1,2 , Helmut Schwab 1,3 , Mélanie Hall 2,* and Kerstin Steiner 1,* a acib, Austrian Centre of Industrial Biotechnology GmbH, Petersgasse 14, 8010 Graz, Austria Fax: ( + 43)-316-873-9302; phone: ( + 43)-316-873-9346; e-mail: kerstin.steiner@acib.at b Department of Chemistry, University of Graz, Heinrichstraße 28, 8010 Graz, Austria Fax: ( + 43)-316-380-9840; phone: ( + 43)-316-380-5479; e-mail: melanie.hall@uni-graz.at c Institute of Molecular Biotechnology, TU Graz, Petersgasse 14, 8010 Graz, Austria Adv .S ynth. Catal. 2015 , 357 , 3 309 –3 316 DOI: 10.1002/adsc.201500608 Abstract A novel biocatalytic oxidative alkene cleavage activity was identified in protein TM1459 from Thermotoga maritima , a so far uncharacterised metalloprotein with a cupin fold, which preferentially binds manganese (over iron and zinc). Various styrene derivat...

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