Phenothiazine Radical Cation Excited States as Super-oxidants for Energy-Demanding Reactions
Citations Over TimeTop 1% of 2018 papers
Abstract
We demonstrate that the 10-phenyl-10 H-phenothiazine radical cation (PTZ+•) has a manifold of excited doublet states accessible using visible and near-infrared light that can serve as super-photooxidants with excited-state potentials is excess of +2.1 V vs SCE to power energy demanding oxidation reactions. Photoexcitation of PTZ+• in CH3CN with a 517 nm laser pulse populates a Dn electronically excited doublet state that decays first to the unrelaxed lowest electronic excited state, D1' (τ 1 (τ = 10.9 ± 0.4 ps), which finally decays to D0 (τ = 32.3 ± 0.8 ps). D1' can also be populated directly using a lower energy 900 nm laser pulse, which results in a longer D1'→D1 relaxation time (τ = 19 ± 2 ps). To probe the oxidative power of PTZ+• photoexcited doublet states, PTZ+• was covalently linked to each of three hole acceptors, perylene (Per), 9,10-diphenylanthracene (DPA), and 10-phenyl-9-anthracenecarbonitrile (ACN), which have oxidation potentials of 1.04, 1.27, and 1.6 V vs SCE, respectively. In all three cases, photoexcitation wavelength dependent ultrafast hole transfer occurs from Dn, D1', or D1 of PTZ+• to Per, DPA, and ACN. The ability to take advantage of the additional oxidative power provided by the upper excited doublet states of PTZ+• will enable applications using this chromophore as a super-oxidant for energy-demanding reactions.
Related Papers
- → Optical and electrochemical properties of ethynylaniline derivatives of phenothiazine, phenothiazine-5-oxide and phenothiazine-5,5-dioxide(2014)36 cited
- → Oxidation Kinetics of Phenothiazine and 10-Methylphenothiazine in Acidic Medium(1977)14 cited
- → Annellation effects in the perylene and coronene series(1966)13 cited
- → Perylene Pigments(2009)13 cited
- → ChemInform Abstract: A NEW STUDY OF THE ELECTROCHEMICAL OXIDATION OF THE PHENOTHIAZINE RING. I. THE CASE OF PHENOTHIAZINE AND ITS 3 AND 7 DISUBSTITUTED DERIVATIVES(1978)