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Electronic Finetuning of a Bio‐inspired Iron(II) tetra‐NHC Complex by trans Axial Isocyanide Substitution
Author(s) -
Schlagintweit Jonas F.,
Hintermeier Carolin,
Anneser Markus R.,
Esslinger EvaMaria H. J.,
Haslinger Stefan,
Kühn Fritz E.
Publication year - 2020
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202000214
Subject(s) - isocyanide , carbene , cyclic voltammetry , chemistry , acetonitrile , tetra , ligand (biochemistry) , medicinal chemistry , redox , stereochemistry , catalysis , electrochemistry , organic chemistry , biochemistry , receptor , electrode
The synthesis of trans axially substituted mono‐ ( 1 a ) and bis( tert ‐butylisocyanide) ( 1 b ) derivatives of the highly active homogeneous bio‐inspired iron(II) olefin epoxidation (pre‐)catalyst 1 bearing an equatorial macrocyclic tetra N ‐heterocyclic carbene and two trans axial labile acetonitrile ligands is reported. NMR spectroscopy and SC‐XRD indicate a considerable π‐backdonation from the iron(II) centres to the isocyanide ligand(s). The impact of isocyanide substitution on the electronic features of the complexes is studied by cyclic voltammetry revealing a significant increase in half‐cell potential assignable to the reversible Fe(II)/Fe(III) redox couple with an increasing number of isocyanides as a result of their π‐accepting properties: E 1/2 =0.15 V ( 1 ), E 1/2 =0.35 V ( 1 a ), E 1/2 =0.44 V ( 1 b ).