Synthesis, X-Ray Crystal Structure and Coupling Reactions of 4,5-($1^{\prime},2^{\prime}$-diphenylethylenedithio)-1,3-dithiole-2-thione (dPhEDT-DTT)

Abstract

A facile synthesis of 4,5-(1',2'-diphenylethylenedithio)-1,3-dithiole-2-thione (dPhEDT-DTT) is carried out via a Diels-Alder type [2+4] cycloaddition reaction of 1,3-dithiol-2,4,5-trithione oligomer and t-stilbene. Molecular structure of dPhEDT-DTT is determined by x-ray crystallography: space group P1, a=11.694(3) Å, b=12.117(3) Å, c=14.688(3) Å, α=113.12(2)°, β=102.23(2)°, γ=107.02(2)°, V= 1699.1(7) Å3, Z=2. It turns out that dPhEDT-DTT crystallizes as a racemic compound consisting of (R,R) and (S,S) enantiomers. Coupling reaction of dPhEDT-DTO undergone in neat P(OEt)3 yields TTF(SEt)4 instead of ET derivative. When PR3 (R=OEt, OPh, Ph) is used in benzene, toluene or xylene, however, dPhEDT-DTO is decomposed.