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
- 16 August 2004
- journal article
- research article
- Published by Wiley in Macromolecular Theory and Simulations
- Vol. 13 (7) , 583-591
- https://doi.org/10.1002/mats.200400007
Abstract
Summary: A DFT method has been applied for quantum‐chemical calculations of the molecular structure of charge‐neutral complex LFeMe(μMe)2AlMe2 which is formed in system LFeMe2 + AlMe3 (L = 2,6‐bis(imino)pyridyl). Calculations suggested the formation of highly polarized complex LFeMe(μMe)2AlMe2 (II) in system LFeMe2 + AlMe3, 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 AlMe3 molecules (complex LFeMe(μMe)2AlMe2 · 2AlMe3 (III)) and with replacement of AlMe3 by MeAlCl2 (complex LFeMe(μMe)2AlCl2 (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 (NH3)3FeMe2; tridentate bis(imino)pyridyl ligand was substituted by three coplanar NH3 groups. image Calculated model complex (NH3)3FeMe2; tridentate bis(imino)pyridyl ligand was substituted by three coplanar NH3 groups.Keywords
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