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The synthesis of the free radicals 1‐(4'‐bromophenyl)‐3,5‐diphenyl‐verdazyl (Br‐TPV), 1‐(4'‐isopropyl‐phenyl)‐3,5‐diphenyl‐verdazyl (IP‐TPV), 1,3,5,6‐tetraphenyl‐verdazyl (Ph‐TPV), 6‐(1′‐naphthyl)‐1,3,5‐tri‐phenyl‐verdazyl (1N‐TPV), 6‐(2′‐naphthyl)‐1,3,5‐triphenyl‐verdazyl (2N‐TPV), 6‐(4′‐bromophenyl)‐1,3,5‐triphenyl‐verdazyl (BrPh‐TPV) and 1,3,5,6,6‐pentaphenyl‐verdazyl (PhPh‐TPV) is described. Their magnetic properties (static magnetic susceptibility, ESR) are reported for crystalline samples. They are compared with those of 1,3,5‐triphenyl‐verdazyl (TPV) which behaves as a quasi‐onedimensional antiferromagnet in the crystalline form. Exchange interaction is increased by a factor larger than 3 compared with TPV by the introduction of the additional ring in Ph‐TPV. For Ph‐TPV and PhPh‐TPV also the crystal structure was derived by X‐ray analysis. These results are discussed with special emphasis on their meaning for the tailoring of magnetic interactions in organic solids.

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Copolymerization of methacrylic acid (M) and acrylonitrile (A) in bulk at 60°C gives a statistical copolymer. Through the use of 1H, 13C, DEPT and twodimensional NMR techniques, the observed resonances in the NMR spectra of these copolymers can be assigned, and thus provide detailed information about the microstructure of the polymer at the diad, triad and tetrad levels. Configurational effects have also been shown to play an important role, although in all cases the chemical shift differences resulting from configurational variation are smaller than those resulting from sequence variation.

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