Iron Complexes Derived from {nacnac-(CH2py)2}− and {nacnac-(CH2py)(CHpy)}n Ligands: Stabilization of Iron(II) via Redox Noninnocence

Valerie A. Williams †, Peter T. Wolczanski *†, Jörg Sutter ‡, Karsten Meyer ‡, Emil B. Lobkovsky †, andThomas R. Cundari §

† Baker Laboratory, Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, United States

‡ Department of Chemistry & Pharmacy, University of Erlangen-Nuremberg, Egerlandstrasse 1. D-91058 Erlangen, Germany

§ Department of Chemistry, Center for Advanced Scientific Computing and Modeling (CASCaM),University of North Texas, Box 305070, Denton, Texas 76203-5070, United States

Inorg. Chem., Article ASAP

DOI: 10.1021/ic5001123

Publication Date (Web): April 24, 2014

*E-mail: ptw2@cornell.edu. Fax: 607 255 4173.

Synopsis

Nanac-based tetradentate chelates, {nacnac-(CH2py)2}− ({nn(PM)2}−) and {nacnac-(CH2py)(CHpy)}n ({nn(PM)(PI)}n), have been applied to iron, and the latter exhibits redox noninnocent behavior (n = 2−) in {nn(PM)(PI)}FeLL′ [2-L,L′; L,L′ = (PMe3)2, (PMe2Ph)2, PMe3(CO)] and {nn(PM)(PI)}FeL (3-L; L = CO, PMe3, PMePh2, PPh3).

Abstract

Nacnac-based tetradentate chelates, {nacnac-(CH2py)2}− ({nn(PM)2}−) and {nacnac-(CH2py)(CHpy)}n ({nn(PM)(PI)}n) have been investigated in iron complexes. Treatment of Fe{N(TMS)2}2(THF) with {nn(PM)2}H afforded {nn(PM)2}FeN(TMS)2 [1-N(TMS)2], which led to {nn(PM)2}FeCl (1-Cl) from HCl and to {nn(PM)2}FeN3 (1-N3) upon salt metathesis. Dehydroamination of 1-N(TMS)2 was induced by L (L = PMe3, CO) to afford {nn(PM)(PI)}Fe(PMe3)2 [2-(PMe3)2] and {nn(PM)(PI)}FeCO (3-CO). Substitution of 2-(PMe3)2 led to {nn(PM)(PI)}Fe(PMe3)CO [2-(PMe3)CO], and exposure to a vacuum provided {nn(PM)(PI)}Fe(PMe3) (3-PMe3). Metathesis routes to {nn(PM)(PI)}FeL2 (2-L2; L = PMe3, PMe2Ph) and {nn(PM)(PI)}FeL (3-L; L = PMePh2, PPh3) from [{nn(PM)(PI)}2–]Li2 and FeBr2(THF)2 in the presence of L proved feasible, and 1e– and 2e– oxidation of 2-(PMe3)2 afforded 2+-(PMe3)2 and22+-(PMe3)2 salts. Mössbauer spectroscopy, structural studies, and calculational assessments revealed the dominance of iron(II) in both high-spin (1-X) and low-spin (2-L2 and 3-L) environments, and the redox noninnocence (RNI) of {nn(PM)(PI)}n [2-L2, 3-L, n = 2–; 2+-(PMe3)2, n = 1–; 22+-(PMe3)2, n = 0]. A discussion regarding the utility of RNI in chemical reactivity is proffered.

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

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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。

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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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