Preparation of New Tetrathiafulvalene (TTF) Derivatives with Two Functional Groups at Symmetrical Positions: 2,6-Diiodo-3,7-diphenyl-TTF, 2,6-Bis[2-(trimethylsilyl)-ethynyl]-3,7-diphenyl-TTF, and 2,6-Diethynyl-3,7-diphenyl-TTF - Shimizu, Takahisa; Koizumi, Take-aki; Yamaguchi, Isao; Osakada, Kohtaro; Yamamoto, Takakazu (Synthesis, 1998)