title: Intense chiroptical switching in a dicationic helicene-like derivative: exploration of a viologen-type redox manifold of a non-racemic helquat.
abstract: Two-step redox switching in enantiopure helquat system [P-1](2+) ⇌ [P-1](•+) ⇌ [P-1](0) is demonstrated. The viologen-type electroactive unit embedded directly in the helical scaffold of 1 is responsible for the prominent chiroptical switching at 264 nm. This process is associated with a marked sign-reversal of Cotton effect ramping between Δε = +35 M(-1) cm(-1) for [P-1](2+) and Δε = -100 M(-1) cm(-1) for [P-1](0). This helically chiral system features the most intense chiroptical switch response documented in the field of helicenoids.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , 16610 Prague, Czech Republic.
authors.forename: Lubomír
authors.initials: L
authors.lastname: Pospíšil
authors.forename: Lucie
authors.initials: L
authors.lastname: Bednárová
authors.forename: Petr
authors.initials: P
authors.lastname: Štěpánek
authors.forename: Petr
authors.initials: P
authors.lastname: Slavíček
authors.forename: Jan
authors.initials: J
authors.lastname: Vávra
authors.forename: Magdaléna
authors.initials: M
authors.lastname: Hromadová
authors.forename: Helena
authors.initials: H
authors.lastname: Dlouhá
authors.forename: Ján
authors.initials: J
authors.lastname: Tarábek
authors.forename: Filip
authors.initials: F
authors.lastname: Teplý