Electrical and magnetic properties of DED salts

The temperature dependence of the electrical resistivity of (DED)(2)PF6(THF)(2), where DED is thiadiazoleethylenedithiodiselenadithiafulvalene, is metallic down to similar to 20 K. At lower temperatures the resistivity rises proportionally to the logarithm of temperature, followed by a saturation of the resistivity upturn at around 1 K. The magnetic susceptibility exhibits Curie-like behavior down to similar to 20 K, and chi T suddenly goes towards zero at lower temperatures. Such behaviour indicates that this salt could be a rare example of 'purely organic' systems whose electrical behavior at low temperatures might be best explained as a result of Kondo effect.