title: Redox switching in ethenyl-bridged bisphospholes.
abstract: A 2e(-) /2H(+) redox platform has been implemented in the ethenyl-bridged bisphosphol-3-ol 1 to afford the first phospholes that feature chemically reversible oxidations. Oxidation of the title compounds to the corresponding bisphosphol-3-one 2 leads to a change in conjugation topology and a concomitant hypsochromic shift of the lowest-energy absorption maximum by 100 nm. Electrochemical oxidation proceeds without any detectable intermediates, whereas the deprotonated form of 1 can be observed in an aprotic medium during the reduction of 2. This dianionic intermediate 3 is characterized by end absorptions that are bathochromically shifted by circa 200 nm compared to those of 2.
authors.affiliation: Department of Chemistry, Ångström Laboratories, Uppsala University, Box 523, 75120 Uppsala (Sweden).
authors.forename: Anna I
authors.initials: AI
authors.lastname: Arkhypchuk
authors.forename: Edgar
authors.initials: E
authors.lastname: Mijangos
authors.forename: Reiner
authors.initials: R
authors.lastname: Lomoth
authors.forename: Sascha
authors.initials: S
authors.lastname: Ott
keywords: conjugation; cyclic voltammetry; electrochromism; phosphaorganic chemistry