Effect of ligand substitution on the exchange interactions in {Mn(12)}-type single-molecule magnets.
We investigate how ligand substitution affects the intramolecular spin exchange interactions, studying a prototypical family of single-molecule magnets comprising dodecanuclear cluster molecules [Mn(III)(8)Mn(IV)(4)O(12)(COOR)(16)]. We identify a simple scheme based on accumulated Pauling electronegativity numbers (AEN) of the carboxylate ligand groups (R). The redistribution of the electron density, controlled by the AEN of a ligand, changes the degree of hybridization between 3d electrons of manganese and 2p electrons of oxygen atoms, thus changing the exchange interactions. This scheme, despite its conceptual simplicity, provides a strong correlation with the exchange energies associated with carboxylate bridges and is confirmed by the electronic structure calculations taking into account the Coulomb correlations in magnetic molecules.
Computational Materials Science Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan. D.Bukhvalov@science.ru.nl
Danil W
DW
Boukhvalov
Viatcheslav V
VV
Dobrovitski
Paul
P
Kögerler
Mohammad
M
Al-Saqer
Mikhail I
MI
Katsnelson
Alexander I
AI
Lichtenstein
Bruce N
BN
Harmon