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Synthesis isolation and magnetic properties of hydrogen-bonded tert-butylnitroxides
Four new stable radicals were synthesized. 2-(tert-butylaminoxyl)benzimidazole, 2-(4-tert-butylnitroxylphenyl)benzimidazole, 5-(6)-chlorobenzimidazole-2- tert-butylnitroxide, 2-(N-tert-butyl-N-aminoxyl)-5,6-dimethylbenzimidazole. According to magnetic studies antiferromagnetic behavior was observed for every sample. However a structure property relationship could be established based on the crystalline packing pattern observed. J exchange coupling was of higher dimensionality where the crystal structure was more ordered (herringbone interactions present), while the coupling was large but merely dimeric for the systems that exhibited lower dimensional, dimeric behavior. DFT calculations for dimeric pairs formed in 5-(6)-chlorobenzimidazole-2- tert-butylnitroxide, 2-(N-tert-butyl-N-aminoxyl)-5,6-dimethylbenzimidazole predicted ferromagnetic interaction opposite to antiferromagnetic behavior observed. These results suggest that the hydrogen bond does not have an appreciable participation in the spin-polarization exchange component of the magnetic behavior in these systems. ^
Jacqueline C Ruiz,
"Synthesis isolation and magnetic properties of hydrogen-bonded tert-butylnitroxides"
(January 1, 2001).
Electronic Doctoral Dissertations for UMass Amherst.