Conducting Charge-Transfer Salts Based On Neutral Π-Radicals
MOST molecular conductors rely on charge transfer to create carriers. For example, the ET salts1 are hole-doped whereas the C60 salts2 are electron-doped. Neutral radical species in which bands are formed by π-orbital overlap would be expected to have half-filled bands and thus to be conducting3, but no such metals have yet been reported. Here we report the synthesis and characterization of a molecular conductor which combines both of these approaches: energy bands are formed from one-dimensional stacks of neutral π-radicals, and the material is rendered conducting by electron transfer from the conduction band following doping with an acceptor. The radical species is the l,4-phenylene-bis(dithiadiazolyl) diradical 1,4-[(S2N2C)C6H4(CN 2S2)] (2 in Fig. 1), reaction of which with iodine vapour leads to crystals of [I]. At low temperatures this compound is essentially a diamagnetic insulator, but above 200 K the conductivity and magnetic susceptibility increase markedly, and at room temperature the conductivity reaches l00 S cm-1, which is comparable to that shown by conventional molecular charge-transfer salts.
MSU Digital Commons Citation
Bryan, C. D.; Cordes, A. Wallace; Fleming, R. M.; George, N. A.; Glarum, Sivert H.; Haddon, Robert C.; Oakley, Richard T.; Palstra, T. T.M.; Perel, A. S.; Schneemeyer, Lynn; and Waszczak, Joseph V., "Conducting Charge-Transfer Salts Based On Neutral Π-Radicals" (1993). Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works. 196.