A dysprosium alkylidene single molecule magnet

Abstract

A dysprosium alkylidene complex, supported by a β-diketiminato-based tridentate ligand and alkylidene ligand [C(SiMe₃)PPh₂Se]²⁻, was synthesized and characterized. It exhibited the shortest DyC bond length of 2.266(3) Å to date. Magnetic measurements indicated that it was an SMM with U_eff of 305 K. Comparing its molecular magnetism and structure with those of the other two dysprosium complexes in the synthetic routine, the dysprosium alkylidene SMM benefited much from the DyC bond. Ab initio calculation revealed high crystal-field axiality despite low symmetry. It showed strong anisotropy at ground states and first excited states. Relaxation occurred through the second excited states theoretically. Our data indicated that building dysprosium complexes with one Dy-ligand multiple bond is a feasible strategy to maintain uniaxial magnetic anisotropy for Dy-SMMs.