Crystal Structure and Magnetic Properties of an Organic Ion-Radical Salt: 1,3'-Diethyl-2,2'-Quinoselenacyanine-[TCNQ]2

The crystal structure and magnetic properties of an organic ion-radical salt, 1,3'-diethyl-2,2'-quinoselenacyanine-[TCNQ] 2 , are reported. The salt forms triclinic crystal in the space group \(P\overline{1}\) with a =14.180(3), b =17.689(2), c =8.244(1)A, α=103.13(1), β=93.14(1), γ=70.06(1)° and Z =2. The spin-susceptibility of the salt shows two broad maxima near 45 and 195 K. A single ESR absorption line is observed for single crystals above 40 K and its linewidth strongly depends on the temperature and external magnetic field direction. On the contrary, two side lines due to an excited triplet state are observed below 40 K with a central line. These experimental results are discussed on the basis of the peculiar crystal structure of the salt.