Two novel 2p–4f complexes [Ln(hfac)3(Nit-Ph-PyIm)]2·CHCl3 (Ln(III) = GdIII (1), TbIII (2)) have been obtained through reacting a nitronyl nitroxide radical ligand Nit-Ph-PyIm (2-[4-[2-(2-pyridinyl)-1H-imidazol-1-yl]-phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) with Ln(hfac)3·2H2O (hfac = hexafluoroacetylacetonate). Interestingly, by introducing Cu(hfac)2, one 2p–3d–4f complex {[Tb(hfac)4]−[Cu(hfac)(Nit-Ph-PyIm)]+}n (3) was synthesized. Compounds 1 and 2 possess the [Ln–radical]2 cyclic dimer structure. In complex 3, two neighboring [Cu(hfac)]+ moieties are linked by a Nit-Ph-PyIm radical, generating a positively charged [Cu(hfac)–radical]+ chain containing [Tb(hfac)4]− as the counterion. In the cation chain, Cu(II)⋯O–N interactions were strongly antiferromagnetic due to the equatorially coordinated NO units. Magnetic studies reveal that compound 3 displays field-induced slow magnetization relaxation, caused by the [Tb(hfac)4]− unit which possess a distorted D4d geometry.
