Theoretically Predicted and Experimentally Observed Relaxation Pathways of two Heterodinuclear 3d‐4f Complexes

Abstract

Abstract. The dinucleating ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl

Validation of Ab‐Initio‐Predicted Magnetic Anisotropies and Magneto‐structural Correlations in Linear Hetero‐trinuclear DyIII‐NiII2 Compounds

“…As mentioned before, the ab initio method used here to compute magnetic anisotropies is not undisputed. [24,33] Together with our earlier similar studies, [32,33] for three series of homoand hetero-di-and tri-nuclear 3d-4f complexes, we find excellent agreement between the ab initio computed electronic/magnetic properties, specifically the magnetic anisotropies, and experimental data, including SQUID measurements, MCD, HF-EPR and paramagnetic NMR, and also including an extensive ligand field analysis. One important advantage of the ab initio in comparison with ligand field calculations is that, in principle, these may be used for predictions in addition to interpretations, i. e. for the "rational design" of new materials.…”

“…Importantly, we are able to show that the ab initio calculated magnetic anisotropy of [Dy III {Ni II (L)} 2 ] + of D calc =−6.7 cm −1 is in excellent agreement with that determined by NMR spectroscopy of D exp =−5.0 cm −1 . In addition to previous similar studies, where we have used HF‐EPR and magnetic circular dichroism (MCD) spectroscopy, together with an extensive ligand field analysis,[ 32 , 33 ] the entire set of experimental data presented here gives us confidence that the theoretical setup used can accurately predict the electronic and magnetic properties of oligonuclear 3d–4f complexes.…”

“…T) which, admittedly, are not very sensitive. In studies related to the present publication, we have reported homodinuclear lanthanide(III) and heterodinuclear 3d–4f systems, where the computational data were validated with a combination of AC and DC SQUID, high‐frequency/high‐field EPR (HF‐EPR) and MCD data, combined with an extensive ligand field analysis based on angular overlap model (AOM) calculations,[ 32 , 33 ] and similar approaches have also been used successfully in the validation of the computed multiplet splitting and relaxation barriers in combination with the respective experimental data of mononuclear dysprosium(III) complexes. [ 34 , 35 ] We now extend this validation with the experimental evaluation of the magnetic anisotropy by paramagnetic NMR spectroscopy as well as single crystal AC SQUID and HF‐EPR experiments of the [Dy III {Ni II (L)} 2 ]ClO 4 complex shown in Scheme 1 ; the structure, magnetism and NMR data of the entire series of [Ln III {Ni II (L)} 2 ] + complexes with Ln=Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu was already reported.…”

Correlation of Structural and Magnetic Properties in a Set of Mononuclear Lanthanide Complexes

“…This paper serves as a continuation of our previous studies, in which we have utilized several spectroscopic and magnetometric techniques to validate our computational data . We have reported both homodinuclear lanthanide(III) and heterodinuclear 3d–4f systems, combining our computed values with alternating and direct current (ac and dc) SQUID, high frequency EPR (HF‐EPR), and magnetic circular dichroism (MCD) data, including extensive ligand field analysis based on angular overlap model (AOM) calculations ,. More recently we have utilized paramagnetic NMR spectroscopy and SQUID measurements to determine the solution and solid‐state magnetic behavior of a series of linear trinuclear Ni II 2 Ln III complexes with Ln=Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu .…”

Role of Single-Ion Anisotropy and Magnetic Exchange Interactions in Suppressing Zero-Field Tunnelling in {3d-4f} Single Molecule Magnets

“…Despite the fact that exchange interactions render such a crucial contribution in quenching QTM behavior, there are only a few reports where these interactions are accurately estimated using experimental means. , On the same note, though experimental techniques, such as inelastic neuron scattering (INS) and multifrequency high-field EPR have been used to probe the magnetic anisotropy in exchange coupled systems, none of them suffice to resolve the directions of the local magnetic anisotropy axis accurately. Rapid progress in quantum chemistry methods and enhanced computational resources remedy such issues through the use of fully ab initio calculations. ,,,,,,,,,,, They have been proven valuable in a profound understanding of the complicated nature of the magnetic properties of anisotropic systems. The exchange interactions in anisotropic {3d-4f} systems could be extracted within the Lines model employing anisotropic contributions, energies, and wave functions from ab initio calculations. ,,,, In this regard, the report of eight complexes covering the four lanthanide metal ions {Dy III , Tb III , Er III , and Ho III } with the variation of Cu II and V IV metals reported by Ishida and co-workers gain importance as these complexes are characterized by high-field high frequency electron paramagnetic resonance (HF-EPR) techniques for the first time .…”