Construction and Magnetic Study of One‐Dimensional Lanthanide–Radical Chains Involving Pyridinone‐Substituted Nitronyl Nitroxide Radicals

A new nitronyl nitroxide radical‐containing pyridinone group (NIT‐PhPyO, 1 ) has been synthesized {NIT‐PhPyO = 2‐[4‐(4‐pyridinone)phenyl]‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide}. By using this functionlized nitronyl nitroxide, two isomorphic lanthanide–nitronyl nitroxide radical compounds [{Ln(hfac) 3 } 3 (NIT‐PhPyO) 2 ] n (Ln = Gd 2 and Dy 3 ; hfac = hexafluoroacetylacetonate) have been successfully obtained. X‐ray spectroscopic analysis reveals that complexes 2 and 3 possess a 1D chain structure with Ln 2 O 2 binuclear units, which represent the first examples of Ln–radical chains involving binuclear Ln 2 O 2 units. Analysis of the magnetic data indicates that a weak antiferromagnetic coupling exists between two Gd 3+ ions, while the magnetic interaction between the Gd III ion and the coordinated nitroxide group is ferromagnetic. Alternating current (ac) magnetic studies indicate that compound 3 displays slow magnetic relaxation behavior at low temperature.