2-(2-methyl-1,3-propanediol)-4,4,5,5-tetramethyl-3-oxylimidazoline 1-oxide- An antiferromagnetically coupled nitronyl nitroxide

The synthesis, X-ray structure, and the magnetic properties of 2-(2-methyl- 1,3-propanediol)-4,4,5,5-tetramethyl-3-oxylimidazoline 1-oxide are describe d. The nitronyl nitroxide packs in stacks of dimers. Two CH2O-H . . .O-N hy drogen bonds and one CH2OH group of each nitronyl nitroxide link two molecu les into a dimer. The additional CH2OH group in each molecule forms CH2O-H . . .O-N hydrogen bonds to a second dimer and so on, leading finally to col umns of dimers. Each column is surrounded by six other columns. The magneti c behaviour of the crystal is strongly temperature dependent, evidence for intermolecular interactions between the molecules at room temperature. DFT calculations support an antiferromagnetic coupling of nitronyl nitroxide mo lecules in the dimer.