Highly Reduced Double-Decker Single-Molecule Magnets Exhibiting Slow Magnetic Relaxation

Abstract

F₆₄Pc₂Ln (<b>1</b>_<b>Ln</b>, Ln = Tb or Lu) represent the first halogenated phthalocyanine double-decker lanthanide complexes, and <b>1</b>_<b>Tb</b> exhibits single-molecule magnet properties as revealed by solid-state magnetometry. The fluorine substituents of the phthalocyanine rings have a dramatic effect on the redox properties of the F₆₄Pc₂Ln complexes, namely, a stabilization of their reduced states. Electrochemical and spectroelectrochemical measurements demonstrate that the <b>1</b>_<b>Tb</b>^{<b>–/2–</b>} and <b>1</b>_<b>Tb</b>^{<b>2–/3–</b>} couples exhibit redox reversibility and that the <b>1</b>_<b>Tb</b>^<b>–</b>, <b>1</b>_<b>Tb</b>^<b>2–</b> and <b>1</b>_<b>Tb</b>^<b>3–</b> species may be prepared by bulk electrolysis in acetone. Low-temperature MCD studies reveal for the first time magnetization hystereses for the super-reduced dianionic and trianionic states of Pc₂Ln