We investigate how the ligand substitution affects the intra-molecular spin exchange interactions, studying a prototypal family of single-molecule magnets comprising dodecanuclear cluster molecules [Mn12O12(COOR)16]. We identify a simple scheme based on accumulated Pauling electronegativity numbers (a.e.n.) of the carboxylate ligand groups (R). The redistribution of the electron density, controlled by a.e.n. 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.
@article{arxiv.1010.1319,
title = {Effect of ligand substitution on the exchange interactions in {Mn12}-type single-molecule magnets},
author = {D. W. Boukhvalov and V. V. Dobrovitski and P. Kögerler and M. Al-Saqer and M. I. Katsnelson and A. I. Lichtenstein and B. N. Harmon},
journal= {arXiv preprint arXiv:1010.1319},
year = {2011}
}
Comments
18 pages, 1 table, 4 figures. Accepted to "Inorganic Chemistry"