Magnetic-properties of 1,4-dihydro-1,2,4-benzotriazin -4-yl radicals

✍ Scribed by Kazuo Mukai; Keiichi Inoue; Norio Achiwa; Javad B. Jamali; Claus Krieger; Franz A. Neugebauer

• Book ID: 103030319
• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 384 KB
• Volume: 224
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)00586-9

✦ Synopsis

Magnetic susceptibilities of 1,4-dihydro-1,3-diphenyl-1,2,4-benzotriazin-4-yl ( DDB 1 ), 3-tert-butyl-1,4-dihydro-1 -phenyl-1,2,4benzotriazin-4-yl ( BDPB 2) and 1 -(4-chloropbenyl) -1,4-dihydro-3-phenyl-1,2,4-benzotriazin-4-yl ( CDPB 3) radicals have been measured in the temperature range of 4.2-300 K. The susceptibility ofDDB 1 and BDPB 2 follows the Curie-Weiss law with a negative Weiss constant of -2.2 and -0.3 K, respectively. The magnetic susceptibility of CDPB 3, on the other hand, exhibits a broad maximum at 138 K. This susceptibility can be interpreted in terms of an alternating antfferromagnetic Heisenberg linear chain model with an exchange interaction of 2J~/k= -220 K and an alternation parameter of ct = J2/Jt = 0.3. The results of the X-ray structure analysis of CDPB 3 support the above explanation.