Isolable zwitterionic pyridinio-semiquinone pi-radicals. Mild and efficient single-step access to stable radicals.
A rational design based on the proton-coupled electron transfer (PCET) concept allows us to structurally characterize for the first time isolable, air- and moisture-stable semiquinone radicals in a zwitterionic neutral form. The presence of an alkoxy and the bulky pyridinio substituents causes only a minor perturbation of either the redox potentials or the spectral UV-vis characteristics of the semiquinone core but significantly stabilizes the new radicals.
Yi
Chenyi
C
Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
Blum
Carmen
C
Liu
Shi-Xia
SX
Keene
Tony D
TD
Frei
Gabriela
G
Neels
Antonia
A
Decurtins
Silvio
S
D016227:Benzoquinones / Q000138:chemical synthesis* / Q000737:chemistry / Q000145:classification*; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
D016227:Benzoquinones; D011725:Pyridines; C025232:semiquinone radicals