Low‐Coordinate Single‐Ion Magnets by Intercalation of Lanthanides into a Phenol Matrix

Abstract

It is very challenging to synthesize stable trivalent rare-earth complexes in which the coordination number is lower than 3 for the high oxidation state, there is a large ion radius and nearly non-bonding character of trivalent lanthanide ions. The bulky phenol ligand ArOH (Ar=2,6-Dipp₂ C₆ H₃ , Dipp=2,6-diisopropylphenyl) was utilized to construct low-coordinate lanthanide compound [(ArO)Ln(OAr')] (Ar'=6-Dipp-2-(2'-ⁱ Pr-6'-CHMe(CH₂^- )C₆ H₃ )C₆ H₃ O^- ; Ln=Tb, Dy, Ho, Er, Tm). These complexes and the free ligand ArOH were isostructural. Magnetic measurements and theoretical studies demonstrated that both the oblate-type dysprosium and prolate-type erbium analogues exhibited single-ion magnet (SIM) behavior. The bulky phenol ligands provided strong uniaxial ligand field, making the dysprosium SIM possessing blocking barrier up to 961 K.