Slow Magnetic Relaxation in Pseudo‐One‐Dimensional 2p‐4f Chains Involving π–π Interactions

Abstract

AbstractThe reactions of the nitronyl nitroxide radical 2‐(p‐nitrophenyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide (NIT‐PhNO2) with Ln(hfac)3 (hfac = hexafluoroacetylacetonate) afford two mononuclear lanthanide nitronyl nitroxide complexes [Ln(hfac)3(NIT‐PhNO2)2]·0.5C7H16 [Ln = GdIII (1), DyIII (2)]. X‐ray structural analysis shows that both complexes have a similar mononuclear structure, in which two NIT‐PhNO2 radicals are bonded to the LnIII center as monodentate ligands through the oxygen atoms of the NO groups. Interestingly, those mononuclear units form a pseudo‐one‐dimensional chain structure through π–π interactions. Direct current (dc) magnetic measurements show that there is ferromagnetic coupling between the lanthanide ion and the radical ligand for both complexes. Alternating current (ac) magnetic susceptibility studies reveal that the DyIII complex shows slow relaxation of magnetization in zero field, which is observed for the first time in a lanthanide–radical complex with a pseudo one‐dimensional structure through π–π interactions.