161Dy Time-Domain Synchrotron Mossbauer Spectroscopy for Investigating Single-Molecule Magnets Incorporating Dy Ions

Time-domain synchrotron Mossbauer spectroscopy (SMS) based on the Mossbauer effect of Dy-161 has been used to investigate the magnetic properties of a Dy-III-based single-molecule magnet (SMM). The magnetic hyperfine field of [Dy(Cy3PO)(2)(H2O)(5)]Br-3 center dot 2 (Cy3PO)(2)H2O center dot 2EtOH is with B-0=582.3(5) T significantly larger than that of the free-ion Dy-III with a H-6(15/2) ground state. This difference is attributed to the influence of the coordinating ligands on the Fermi contact interaction between the s and 4f electrons of the Dy-III ion. This study demonstrates that Dy-161 SMS is an effective local probe of the influence of the coordinating ligands on the magnetic structure of Dy-containing compounds.