Physics

Organic chemistry

Lanthanide

Relaxation (psychology)

Magnetization

Terbium

Crystallography

Ferromagnetism

Magnetic field

Psychology

Inorganic chemistry

Chemistry

Magnetism

Condensed matter physics

Metallocene

Molecule

Polymerization

Dysprosium

Quantum mechanics

Divalent

Magnetic relaxation

Polymer

Social psychology

Journal of the American Chemical Society

The divalent metallocene complexes Ln(CpiPr5)2 (Ln = Tb, Dy) were synthesized through the KC8 reduction of Ln(CpiPr5)2I intermediates and represent the first examples of neutral, linear metallocenes for these elements. X-ray diffraction analysis, density functional theory calculations, and magnetic susceptibility measurements indicate a 4fn5d1 electron configuration with strong s/d mixing that supports the linear coordination geometry. A comparison of the magnetic relaxation behavior of the two divalent metallocenes relative to salts of their trivalent counterparts, [Ln(CpiPr5)2][B(C6F5)4], reveals that lanthanide reduction has opposing effects for dysprosium and terbium, with magnetic relaxation times increasing from TbIII to TbII and decreasing from DyIII to DyII. The impact of this effect is most notably evident for Tb(CpiPr5)2, which displays an effective thermal barrier to magnetic relaxation of 1205 cm-1 and a 100-s blocking temperature of 52 K, the highest values yet observed for any nondysprosium single-molecule magnet.

Synthesis and Magnetism of Neutral, Linear Metallocene Complexes of Terbium(II) and Dysprosium(II)