A Reduced (β-Diketiminato)iron Complex with End-On and Side-On Nitriles: Strong Backbonding or Ligand Non-Innocence?
Article first published online: 10 OCT 2011
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
European Journal of Inorganic Chemistry
Special Issue: Coopertive & Redox Non-Innocent Ligands in Directing Organometallic Reactivity (Cluster Issue)
Volume 2012, Issue 3, pages 479–483, January 2012
How to Cite
Cowley, R. E., Christian, G. J., Brennessel, W. W., Neese, F. and Holland, P. L. (2012), A Reduced (β-Diketiminato)iron Complex with End-On and Side-On Nitriles: Strong Backbonding or Ligand Non-Innocence?. Eur. J. Inorg. Chem., 2012: 479–483. doi: 10.1002/ejic.201100787
- Issue published online: 16 JAN 2012
- Article first published online: 10 OCT 2011
- Manuscript Received: 27 JUL 2011
- National Science Foundation. Grant Number: CHE-0911314
- University of Rochester. Grant Number: CHE-0650456
- Density functional calculations;
- Pi interactions
Treatment of the iron(I) synthon LMeFeNNFeLMe (LMe = β-diketiminato ligand) with pivalonitrile gives a formally iron(I) complex LMeFe(NCtBu)2, which has one strongly bound side-on nitrile and one weakly bound end-on nitrile ligand. The side-on nitrile ligand has N–C–C bending and N–C weakening that suggests partial reduction of the nitrile group. The S = 3/2 ground state of this molecule can be described as either an iron(II) atom with a nitrile radical anion or an iron(I) atom that is strongly backbonding. DFT computations show that strong backbonding comes from a doubly occupied orbital, and that there is little ligand radical character. Therefore, the iron(I) formulation is the most appropriate. This study exemplifies how one-electron transfer to ligands and two-electron backbonding to ligands may be distinguished by using spectroscopically calibrated and validated computations.