Molecular structure, bonding analysis and redox properties of transition metal–Hapca [bis(3-aminopyrazine-2-carboxylic acid)] complexes: A theoretical study.
In: Polyhedron, Jg. 91 (2015-05-08), S. 59-67
Online
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Zugriff:
Density functional theory (DFT) calculations were carried out on M(Hapca) 2 (H 2 O) 2 (M = Mn, Fe, Co, Ni and Hapca = bis(3-aminopyrazine-2-carboxylic acid) by means of the BP86 and B3LYP functional using the TZP basis set. The optimized structures were obtained by imposing C 2 or C i symmetries. The C i structural arrangement consists of a slightly distorted octahedron centered by a transition-metal with bidentate Hapca ligands situated in equatorial positions and water molecules in axial ones. However, the C 2 structure consists of a distorted arrangement with n con-planar Hapca ligands. The influence induced by including double polarized functions in the (TZ2P) basis set is small on the geometrical parameters. A bonding analysis of these species showed the weakness of M–O(H 2 O) bonds compared to M–O(Hapca) ones. The obtained MO diagrams showed substantial HOMO–LUMO gaps for the 18-MVE closed-shell configuration. Reduction of M(Hapca) 2 (H 2 O) 2 led to the loss of the two water molecules, inducing four electrons downwards for [Co] − and [Ni] species. The calculated ionization potentials (IPs) and electronic affinities (EAs) showed the oxidation and reduction ease of the manganese species contrarily to the cobalt ones. A diffuse function in the basis set (QZ3P- n diffuse, n = 1 or 2) reduces remarkably the adiabatic electron affinities (AEAs). [ABSTRACT FROM AUTHOR]
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Molecular structure, bonding analysis and redox properties of transition metal–Hapca [bis(3-aminopyrazine-2-carboxylic acid)] complexes: A theoretical study.
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Autor/in / Beteiligte Person: | Benhamada, Nora ; Bouchene, Rafika ; Bouacida, Sofiane ; Zouchoune, Bachir |
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Zeitschrift: | Polyhedron, Jg. 91 (2015-05-08), S. 59-67 |
Veröffentlichung: | 2015 |
Medientyp: | academicJournal |
ISSN: | 0277-5387 (print) |
DOI: | 10.1016/j.poly.2014.12.042 |
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