TY - JOUR

T1 - High-Pressure Crystallography as a Guide in the Design of Single-Molecule Magnets

AU - Thiel, Andreas Munch

AU - Damgaard-Møller, Emil

AU - Overgaard, Jacob

PY - 2020

Y1 - 2020

N2 - Single-molecule magnet materials owe their function to the presence of significant magnetic anisotropy, which arises from the interplay between the ligand field and spin-orbit coupling, and this is responsible for setting up an energy barrier for magnetic relaxation. Therefore, chemical control of magnetic anisotropy is a central challenge in the quest to synthesize new molecular nanomagnets with improved properties. There have been several reports of design principles targeting such control; however, these principles rely on idealized geometries, which are rarely obtained in crystal structures. Here, we present the results of high-pressure single-crystal diffraction on the single-ion magnet, Co(SPh) 4(PPh 4) 2, in the pressure range of 0-9.2 GPa. Upon pressurization a sequence of small geometrical distortions of the central CoS 4 moeity are observed, enabling a thorough analysis of the magneto-structural correlations. The magneto-structural correlations are investigated by theoretical analyses of the pressure-dependent experimental molecular structures. We observed a significant increase in the magnitude of the zero-field splitting parameter D, from -54.6 cm -1 to -89.7 cm -1, which was clearly explained from the reduction of the energy difference between the essential d xy and d x 2-y 2 orbitals, and structurally assigned to the change of an angle of compression of the CoS 4 moeity.

AB - Single-molecule magnet materials owe their function to the presence of significant magnetic anisotropy, which arises from the interplay between the ligand field and spin-orbit coupling, and this is responsible for setting up an energy barrier for magnetic relaxation. Therefore, chemical control of magnetic anisotropy is a central challenge in the quest to synthesize new molecular nanomagnets with improved properties. There have been several reports of design principles targeting such control; however, these principles rely on idealized geometries, which are rarely obtained in crystal structures. Here, we present the results of high-pressure single-crystal diffraction on the single-ion magnet, Co(SPh) 4(PPh 4) 2, in the pressure range of 0-9.2 GPa. Upon pressurization a sequence of small geometrical distortions of the central CoS 4 moeity are observed, enabling a thorough analysis of the magneto-structural correlations. The magneto-structural correlations are investigated by theoretical analyses of the pressure-dependent experimental molecular structures. We observed a significant increase in the magnitude of the zero-field splitting parameter D, from -54.6 cm -1 to -89.7 cm -1, which was clearly explained from the reduction of the energy difference between the essential d xy and d x 2-y 2 orbitals, and structurally assigned to the change of an angle of compression of the CoS 4 moeity.

KW - ANISOTROPY

KW - BARRIER

KW - COMPLEX

KW - CRYSTAL

KW - MAGNETOSTRUCTURAL CORRELATIONS

KW - ORIGIN

KW - RELAXATION

KW - SYMMETRY

KW - ZERO-FIELD

U2 - 10.1021/acs.inorgchem.9b02794

DO - 10.1021/acs.inorgchem.9b02794

M3 - Journal article

C2 - 31944683

VL - 59

SP - 1682

EP - 1691

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 3

ER -