A DFT Quantum-Chemical Study of the Structure of Precursors and Active Sites of Catalyst Based on 2,6-Bis(imino)pyridyl Fe(II) Complexes
✍ Scribed by Ivan I. Zakharov; Vladimir A. Zakharov
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 325 KB
- Volume
- 13
- Category
- Article
- ISSN
- 1022-1344
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✦ Synopsis
Abstract
Summary: A DFT method has been applied for quantum‐chemical calculations of the molecular structure of charge‐neutral complex LFeMe(μMe)~2~AlMe~2~ which is formed in system LFeMe~2~ + AlMe~3~ (L = 2,6‐bis(imino)pyridyl). Calculations suggested the formation of highly polarized complex LFeMe(μMe)~2~AlMe~2~ (II) in system LFeMe~2~ + AlMe~3~, characterized by r(FeμMe) = 3.70 Å and r(AlμMe) = 2.08 Å and deficient electron density on fragment [LFeMe]^Q^ (Q = +0.80 e). Polarization of the complex progresses with the bounding of two AlMe~3~ molecules (complex LFeMe(μMe)~2~AlMe~2~ · 2AlMe~3~ (III)) and with replacement of AlMe~3~ by MeAlCl~2~ (complex LFeMe(μMe)~2~AlCl~2~ (IV)). The activation energy of ethylene insertion into the FeMe bond of these complexes has been calculated. It was found that the heat of π‐complex formation increases with increasing of polarization extent in the order II < III < IV. Activation energy of the insertion of coordinated ethylene into FeMe bond decreases in the same order: II > III > IV.
Calculated model complex (NH~3~)~3~FeMe~2~; tridentate bis(imino)pyridyl ligand was substituted by three coplanar NH~3~ groups.
imageCalculated model complex (NH~3~)~3~FeMe~2~; tridentate bis(imino)pyridyl ligand was substituted by three coplanar NH~3~ groups.