Disparate reactivity from isomeric {Me 2 C(CH 2 N CHpy) 2 } and {Me 2 C(CH NCH 2 py) 2 } chelates in iron complexation
摘要:
Cyclizations of R2C(HCNCH2(2-py))(2) (R-2 = Me-2, dmp(PM)(2); R-2 = (CH2)(4), cpp(PM)(2)) to 4,4-dimethyl-2-(pyridin-2-yl)-N-(pyridin-2-ylmethylene)pyrrolidin-3-amine and 3-(pyridin-2-yl)-N-(pyridin-2-ylmethylene)-2-azaspiro-[4.4]-nonan-4-amine, respectively, were catalyzed by 10 mol% Fe{N(TMS)(2)}(2)(THF). A complex with the stoichiometry {Me2C(HCNCH2(2-py))(CHCNCH(2-py))}FeN(TMS)(2) (2-N(TMS)(2)) was shown to be catalytically competent. In contrast, the isomer Me2C(CH2NCH(2-py)H)(2) (dmp(PI)(2)) did not cyclize nor isomerize with Fe{N(TMS)(2)}(2)(THF), but generated {dmp(PI)(2)}FePMe3 (Fe-PMe3) when treated with (Me3P)(3)HFe(eta(2)-PMe2CH2). Calculations of Fe-L (L = PMe3, CO) support the electronics suggested by the metrics of its crystal structure, which revealed the chelate to be {dmp(PI)(2)}(2-) ligated to Fe(II). Electrochemical and brief reactivity studies were consistent with redox activity occurring at the chelate ligand, while the iron likely remains Fe(II). (C) 2014 Elsevier Ltd. All rights reserved.
Iron(II) Cage Complexes of N-Heterocyclic Amide and Bis(trimethylsilyl)amide Ligands: Synthesis, Structure, and Magnetic Properties
作者:Scott A. Sulway、David Collison、Joseph J. W. McDouall、Floriana Tuna、Richard A. Layfield
DOI:10.1021/ic102341a
日期:2011.3.21
[FeN(SiMe3)2}2] (1) produces the trimetallic iron(II) amide cagecomplex [(Me3Si)2NFe}2(hpp)4Fe] (2), which contains three iron(II) centers, each of which resides in a distorted tetrahedral environment. An alternative, one-pot route that avoids use of the highly air-sensitive complex 1 is described for the synthesis of the iron(II)−lithium complex [(Me3Si)2N}2FeLi(bta)}]2 (3) (where btaH = benzotriazole)
Molecularly well‐definedironpincer complexes promote the aqueous‐phase reforming of methanol to carbon dioxide and hydrogen, which is of interest in the context of a methanol and hydrogen economy. For the first time, the use of earth‐abundant iron complexes undermildconditions for efficient hydrogen generation from alcohols is demonstrated.
Synthesis, characterization and derivatization of hydroxyl-functionalized iron(<scp>ii</scp>) bis(NHC) complexes
作者:Anja C. Lindhorst、Manuel Kaspar、Philipp J. Altmann、Alexander Pöthig、Fritz E. Kühn
DOI:10.1039/c7dt04774f
日期:——
hydroxyl-functionalized tetradentate NHC/pyridine hybrid ligand and the corresponding Ag(I) and Fe(II) complexes are presented. Spectroscopic and X-ray diffraction techniques are used for structural investigations and cyclic voltammetry measurements reveal interesting electronic properties. Transmetalation of the trinuclear Ag(I) complex (C1) yields a mononuclear and a dinuclear iron(II) bis(NHC) complex (C2
Aryl−Oxazoline Chelates of First-Row Transition Metals: Structures of {κ-<i>C</i>,<i>N</i>-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub>(COCH<sub>2</sub>CMe<sub>2</sub>N)}FeCl(py) and [(κ-<i>C</i>,<i>N</i>-(<i>o</i>-C<sub>6</sub>H<sub>4</sub>)CMe<sub>2</sub>(COCH<sub>2</sub>CMe<sub>2</sub>N)}Cr(μ-Cl)]<sub>2</sub>
作者:Emily C. Volpe、David R. Manke、Erika R. Bartholomew、Peter T. Wolczanski、Emil B. Lobkovsky
DOI:10.1021/om100420z
日期:2010.12.27
(Me2N)3Ti(η-N-(4,4-dimethyl-(2-CHPh)oxazoline)) (2) and bis-N,N′-(4,4-dimethyl-(2-pyridylmethylyl)oxazoline)Fe (3). Oxidative addition of 4,4-dimethyl-2-(2-bromophenylpropan-2-yl)oxazoline (BrPhCMe2Ox) to Ni(COD)2 provided [κ-C,N-(o-C6H4)CMe2(COCH2CMe2N)}Ni]2(μ-Br)2 (42). With 4,4-dimethyl-2-(2-lithiophenylpropan-2-yl)oxazoline (LiPhCMe2Ox), salt (FeBr2) metathesis proved uncompetitive with oxazoline ring-opening
interactions in neutral compounds. A set of iron compounds was shown to be active as precatalysts in the synthesis of poly silylethers by dehydrogenative alcoholysis of PhSiH3. The most active catalyst was generated from a dinuclear iron compound. Characterization techniques include NMR, IR, and Mössbauer spectroscopy, single crystal X-ray analysis, magnetic susceptibility measurements, and mass spectrometry