Crystal engineering and magnetism of hydrogen-bonded phenyl nitronyl nitroxides

A new phenyl nitronyl nitroxide (R)-3LNN bearing a chiral substituent has been designed and synthesized with the aim of combining the magnetic properties of this kind of radicals with the optical properties given by the chiral group. This optically active carboxylic acid forms hydrogen bonds to the NO unit which control the solid state structure, and consequently the magnetic properties. We present both the solution properties and the solid state structure as well as the magnetic susceptibility curve of this radical. The X-ray structure shows that from the crystal engineering point of view this radical packs in a similar way to the achiral 4OHNN, which has been deeply studied. The magnetic behaviours and the crystal packings of both radicals are compared and discussed.