Ethylenedithio-tetrathiafulvalene-helicenes: electroactive helical precursors with switchable chiroptical properties.
Electroactive fused ethylenedithio-tetrathiafulvalene-[4]helicene and -[6]helicenes have been synthesized through a strategy that involved the preparation of 2,3-dibromo-helicene derivatives as intermediates. The dihedral angles between the terminal helicenes, as determined by single-crystal X-ray analysis, are 22.7° and 50.7° for the [4]helicene and [6]helicene, respectively. Their solid-state architectures show interplay between S⋅⋅⋅S and π⋅⋅⋅π intermolecular interactions. The chiroptical properties of the enantiopure EDT-TTF-[6]helicene derivatives have been investigated and supported by TDDFT calculations. Remarkable redox switching of the circular dichroism (CD) signal between the neutral and radical-cation species has been achieved.
Université d'Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 bd Lavoisier, 49045 Angers (France), Fax: (+33) 02-41-73-54-05.
Thomas
T
Biet
Arnaud
A
Fihey
Thomas
T
Cauchy
Nicolas
N
Vanthuyne
Christian
C
Roussel
Jeanne
J
Crassous
Narcis
N
Avarvari
chirality; chiroptical properties; helical structures; structure elucidation; tetrathiafulvalenes