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Quantitative estimation of ising-type magnetic anisotropy in a family of C-3-symmetric Co-II complexes Mondal, Amit Kumar Jover Modrego, Jesús Ruiz Sabín, Eliseo Konar, Sanjit Imants Anisotropia Lligands Magnets Anisotropy Ligands In this paper, the influence of the structural and chemical effects on the Ising-type magnetic anisotropy of pentacoordinate Co-II complexes has been investigated by using a combined experimental and theoretical approach. For this, a deliberate design and synthesis of four pentacoordinate Co-II complexes [Co(tpa)Cl]ClO4 (1), [Co(tpa)Br]ClO4 (2), [Co(tbta)Cl](ClO4)(MeCN)(2)(H2O) (3) and [Co(tbta)Br]ClO4 (4) by using the tripodal ligands tris(2-methylpyridyl)amine (tpa) and tris[(1-benzyl-1H-1,2,3-triazole-4-yl)methyl]amine) (tbta) have been carried out. Detailed dc and ac measurements show the existence of field-induced slow magnetic relaxation behavior of Co-II centers with Ising-type magnetic anisotropy. A quantitative estimation of the zero-field splitting (ZFS) parameters has been effectively achieved by using detailed ab initio theory calculations. Computational studies reveal that the wavefunction of all the studied complexes has a very strong multiconfigurational character that stabilizes the largest m(s)=+/- 3/2 components of the quartet state and hence produce a large negative contribution to the ZFS parameters. The difference in the magnitudes of the Ising-type anisotropy can be explained through ligand field theory considerations, that is, D is larger and negative in the case of weak equatorial sigma-donating and strong apical -donating ligands. To elucidate the role of intermolecular interactions in the magnetic relaxation behavior between adjacent Co-II centers, a diamagnetic isostructural Zn-II analog (5) was synthesized and the magnetic dilution experiment was performed. 2019-10-22T11:57:48Z 2019-10-22T11:57:48Z 2017-09-12 2019-10-22T11:57:49Z info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Versió postprint del document publicat a: https://doi.org/10.1002/chem.201702108 Chemistry-A European Journal, 2017, vol. 23, num. 51, p. 12550-12558 https://doi.org/10.1002/chem.201702108 (c) Wiley-VCH, 2017 info:eu-repo/semantics/openAccess Wiley-VCH Articles publicats en revistes (Química Inorgànica i Orgànica)