Magnetic-Behavior of 1,3-[(S2n2c)c6h4(cn2s2)] from Nmr Measurements

by Allen, L. C.; Warren, W. W.; Haddon, Robert C.; Oakley, Richard T.; Cordes, A. Wallace

The proton spin-lattice relaxation rate of the organic bifunctional dithiadiazolyl biradical 1,3-[(S2N2C)C6H4(CN2S2)] was measured at two NMR frequencies, 15.6 and 31.0 MHz. Data in the temperature range 350-480 K exhibit an enhancement in the rate consistent with magnetic-susceptibility results. The relaxation rate has a frequency-dependent part attributed to slow molecular motions, and a frequency-independent and strongly temperature-dependent spin motion contribution associated with free radicals. In addition to the increase in spin number, our results show an increase in the rate of spin fluctuation with temperature. A quantification of the motional rate extracted from these data does not support the speculation that these spins are the carriers that cause the increase in the electrical conductivity observed in the same temperature range.

Journal
Physical Review B (Solid State)
Volume
43
Issue
13
Year
1991
Start Page
11456
ISBN/ISSN
0556-2805
DOI
10.1103/PhysRevB.43.11456