TAILORING MAGNETIC-INTERACTIONS OF ORGANIC-SOLIDS - MODIFICATION OF TRIPHENYLVERDAZYL

The synthesis of the free radicals 1-(4'-bromophenyl)-3,5-diphenyl-verdazyl (Br-TPV), 1-(4'-isopropylphenyl)-3,5-diphenyl-verdazyl (IP-TPV), 1,3,5,6-tetraphenyl-verdazyl (Ph-TPV), 6-(1'-naphthyl)-1,3,5-triphenyl-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.