Definition of magneto-structural correlations for the MnII ion.
The electronic properties of the high spin mononuclear MnII complexes [Mn(tpa)(NCS)2] (1) (tpa = tris-2-picolylamine), [Mn(tBu3-terpy)2](PF6)2 (2) (tBu3-terpy = 4,4',4"-tri-tert-butyl-2,2':6',2"-terpyridine) and [Mn(terpy)2](I)2 (3) (terpy = 2,2':6',2"-terpyridine) with an N6 coordination sphere were detd. by multifrequency EPR spectroscopy. The x-ray structures of 1·MeCN and 2·C4H10O·0.5EtOH·0.5MeOH reveal that the MnII ion lies at the center of a distorted octahedron. Crystallog. data are given. The D-values of 1-3 all fall in the narrow range of 0.041 to 0.105 cm-1. The comparison of the results reported here and those found in the literature is consistent with the following observation: the D value is sensitive to the coordination no. (6 or 5) of the MnII ion as long as the coordination sphere involves only N and/or O based ligands. This magneto-structural correlation was analyzed in this work though DFT model calcns. The zero-field splitting (zfs) parameters of 1-3 were calcd. and are in reasonable agreement with the exptl. values. Hypothetical simplified models [Mn(NH3)x(OH2)y]2+ (x+y = 5 or 6 and [Mn(NH3)5X]+ (X = OH, Cl)) were constructed to study the origin of the zfs. This study reveals (i) that D is sensitive to the coordination no. (5 or 6) of the MnII ion, (ii) for the five coordinate systems the major contribution to D is the spin-orbit coupling part, (iii) for the six coordinate systems the major contribution to D is the spin-spin interaction and (iv) the deprotonation of a H2O ligand increases D, consistent with the relative ligand fields of OH- vs. H2O. [on SciFinder(R)]
Références
- Titre
- Definition of magneto-structural correlations for the MnII ion.
- Type de publication
- Article de revue
- Année de publication
- 2008
- Auteurs
- Duboc, Carole, Collomb Marie-Noelle, Pécaut Jacques, Deronizer Alain, and Neese Frank
- Revue
- Chem. - A Eur. J.
- Volume
- 14
- Pagination
- 6498–6509
- ISSN
- 0947-6539
- Mots-clés
- crystal structure manganese picolylamine tertbutylterpyridine iodo terpyridine definition magnetostructural correlation manganese ion coordination compd ESR magnetostructural correlation manganese coordination compd mol structure manganese picolylamine tertbutylterpyridine iodo terpyridine spin orbit coupling manganese coordination compd magnetostructural correlation
Soumis le 12 avril 2018