A stable dysprosium(III) complex with a terminal fluoride ligand showing high resolution luminescence and slow magnetic relaxation

An air-stable dysprosium(III) complex, [C(NH2)(3)](4)[DyF(piv)(4)]( piv)(2) ( piv = pivalate), with a terminal fluoride ligand protected by forming extensive hydrogen bonds with peripheral guanidiniums has been isolated. Though the magnetic data failed to determine the energy barrier for the magnetic reversal (U-eff) accurately, the fine emission spectrum of the F-4(9/2) -> H-6(15/2) transition at 4.2 K and ab initio calculations reveal that the U-eff is about 376(20) K, which is among the highest for high-coordinate (coordination numbers >= 9) lanthanide mononuclear magnets.