Two mononuclear complexes of formula (Et3BzN)2[ReCl6] (1) and (Et3BzN)2[PtCl6] (2) (Et3BzN+ = triethylbenzylammonium cation) have been synthesized in good yield (70 and 75 %, respectively) and structurally characterized. From a structural point of view, they both crystallized in the monoclinic centrosymmetric P21/n space group and the two molecular structures are almost perfectly superimposable, with only minor differences in the M–Cl bond lengths. Solid-state direct-current (dc) magnetic susceptibility analysis in the temperature range 1.9–300 K for 1 reveal the occurrence of magnetically isolated rhenium(IV) ions with a significant zero-field splitting (zfs), D = +6.7 cm–1 (2D being the energy gap between the MS = ±3/2 and MS = ±1/2 Kramers doublets). DFT, CASSCF and CASSCF/NEVPT2 theoretical calculations were carried out on the experimental geometry of the complex [ReCl6]2– in 1 to substantiate the parameters defining the zfs tensor. Alternating current (ac) magnetic susceptibility measurements of 1 in the temperature 2.0–10 K show incipient frequency–dependence of the out-of-phase signals below 3.0 K under non-zero applied dc fields supporting a field–dependent Single Ion Single Molecule Magnet (SISMM) behaviour of this rhenium(IV) derivative.
Magnetic Properties of a New Hexahalorhenate(IV) Compound and Structural Comparison with Its Hexahaloplatinate(IV) Analog
Dolmella A.
2020
Abstract
Two mononuclear complexes of formula (Et3BzN)2[ReCl6] (1) and (Et3BzN)2[PtCl6] (2) (Et3BzN+ = triethylbenzylammonium cation) have been synthesized in good yield (70 and 75 %, respectively) and structurally characterized. From a structural point of view, they both crystallized in the monoclinic centrosymmetric P21/n space group and the two molecular structures are almost perfectly superimposable, with only minor differences in the M–Cl bond lengths. Solid-state direct-current (dc) magnetic susceptibility analysis in the temperature range 1.9–300 K for 1 reveal the occurrence of magnetically isolated rhenium(IV) ions with a significant zero-field splitting (zfs), D = +6.7 cm–1 (2D being the energy gap between the MS = ±3/2 and MS = ±1/2 Kramers doublets). DFT, CASSCF and CASSCF/NEVPT2 theoretical calculations were carried out on the experimental geometry of the complex [ReCl6]2– in 1 to substantiate the parameters defining the zfs tensor. Alternating current (ac) magnetic susceptibility measurements of 1 in the temperature 2.0–10 K show incipient frequency–dependence of the out-of-phase signals below 3.0 K under non-zero applied dc fields supporting a field–dependent Single Ion Single Molecule Magnet (SISMM) behaviour of this rhenium(IV) derivative.
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