Magnetic properties of 1,5-dimethylverdazyl radicals. I. Evidence for the ferromagnetic exchange interaction in 3-(4-chlorophenyl)-1,5-dimethyl-6-thioxoverdazyl radical solid

✍ Scribed by Kazuo Mukai; Kouichi Nedachi; Javad B. Jamali; Norio Achiwa

• Book ID: 103033081
• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 303 KB
• Volume: 214
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)85683-f

✦ Synopsis

Magnetic susceptibilities of 3-( 4_chlorophenyl)-I$-dimethyl&bioxoverdazyl (pCDTV) and 3-(4-bromophenyl)-dthioxoverdazyl (pBDTV) radicals have been measured in the temperature range between 4.0 and 300 K. The susceptibility ofpCDTV follows the Curie-Weiss law with a Curie constant of 0.381 K emu/mol and a positive Weiss constant of 0= + 3.2 K, suggesting intermolecular ferromagnetic exchange interaction between neighboring radicals. On the other hand, the magnetic susceptibility ofpBDTV exhibits a broad maximum at 26.5 K. This susceptibility can be explained by the one-dimensional Heisenberg model with negative exchange interaction of U/k = -4 1.3 K.