The requirement of high magnetic anisotropy and strong magnetic coupling to enhance the performance of single molecule magnets (SMMs) has led researchers to focus their attention on radical-bridged metal complexes. Among 3d and 4f ions, high spin Co(II) as well as Dy(III) are of particular interest due to their specific single ion anisotropy. Our group has recently synthesized the first examples of tetrazine radical bridged metallacycles containing these metal ions, viz., Co3(dbm)3(bptz)3, Co4(dbm)4(bptz)4, and Dy3(hfac)6(bptz)3 (dbm = 1,3-diphenyl-1,3-propanedionate; hfac = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; bptz = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine). In order to understand the magnetic properties and the origin of magnetic anisotropy in these compounds, we performed DFT and ab initio calculations at the CASSCF level, including the spin-orbit coupling within the SO-RASSI approach. For the Co(II) motifs, we were able to rationalize the origin of positive zero field splitting parameter (D) and the strong antiferromagnetic Co-bptz magnetic coupling. For the first time, the exchange interaction between Dy-bptz in Dy3 triangle was computed within the Lines model by using POLY_ANISO program. The simulation of magnetic susceptibility is in good agreement with the experimental data, supporting the calculations presented here.

Theoretical investigations on radical bridged supramolecular metallacycles toward exploring single molecular magnets

255th National Meeting (2018)

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