Structure and Magnetic Properties of a Gadolinium Hexafluoroacetylacetonate Adduct with the Radical 4,4,5,5‐tetramethyl‐2‐phenyl‐4,5‐dihydro‐1H‐imidazole 3‐Oxide 1‐Oxyl

A distorted dodecahedral array of eight O atoms surround the Gd3⊕ ion in 2, the first stable adduct of an organic radical (1) and a lanthanoid ion. From the temperature-dependence of the magnetic susceptibility of 2 it can be concluded that there is a weak ferromagnetic interaction between GdIII and the unpaired electrons of two radicals as well as an antiferromagnetic interaction between the two radicals. f-Metal orbitals participate in the magnetic interaction, as was shown by an angular overlap analysis.