Evidence of the central tetrathiafulvalene bond opening by copper(II) salts. In situ generation of 2,3-bis(2′-cyanoethylchalcogeno)-7,8-benzo-1,4,6,9-tetrathia-10-ceto spiro[4,5]decane

The two-electrons oxidation of 4,5-benzo-6,7-bis(2′-cyanoethylthio) TTF (CETBz-TTF) and 4,5-benzo-6,7-bis(2′-cyanoethylseleno) TTF (CESBz-TTF) with Cu2+X2 (X = Cl−, BF 4 - ) leads to the formation of 2,3-bis(2′-cyanoethylchalcogeno)-7,8-benzo-1,4,6,9-tetrathia-10-ceto spiro[4,5]decane after opening of the –C–S– bond of the central TTF core.