Unknown

Dataset Information

0

Combining energy and electron transfer in a supramolecular environment for the "green" generation and utilization of hydrated electrons through photoredox catalysis.


ABSTRACT: We present a new mechanism that sustainably produces hydrated electrons, i.e., extremely strong reductants, yet consumes only green photons (532 nm) and the bioavailable ascorbate as sacrificial donor. The mechanism couples an energy-transfer cycle, in which a light-harvesting ruthenium polypyridine complex absorbs a first photon and passes the excitation energy on to a pyrene-based redox catalyst, with an electron-transfer cycle, in which the resulting triplet is reductively quenched and the energy-rich aryl radical anion is finally ionized by a second photon. Thus separating the roles of primary and secondary absorber permitted choosing a redox catalyst with a nonabsorbing ground state but efficiently ionizable radical anion; the quantum yield of the ionization step in our complex mechanism surpasses that in a simple photoredox cycle featuring only the metal complex by a factor of four. We suppressed undesired cross reactions through the noncovalent interactions of an anionic micelle with the charges of the reactants, intermediates, and products: the cationic light-harvesting complex remains affixed to the micelle surface, which blocks the access of the negatively charged sacrificial donor, aryl radical anion and hydrated electron, but allows the pyrene ground-state almost unhindered entry into the Stern layer despite a carboxylate substituent by virtue of its large dipole moment. We demonstrate the applicability of the mechanism to the reductive detoxification of halogenated organic waste, which hitherto required UV-C for electron generation, by decomposing the typical model compound chloroacetate.

SUBMITTER: Kerzig C 

PROVIDER: S-EPMC6013799 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature

altmetric image

Publications

Combining energy and electron transfer in a supramolecular environment for the "green" generation and utilization of hydrated electrons through photoredox catalysis.

Kerzig Christoph C   Goez Martin M  

Chemical science 20160301 6


We present a new mechanism that sustainably produces hydrated electrons, <i>i.e.</i>, extremely strong reductants, yet consumes only green photons (532 nm) and the bioavailable ascorbate as sacrificial donor. The mechanism couples an energy-transfer cycle, in which a light-harvesting ruthenium polypyridine complex absorbs a first photon and passes the excitation energy on to a pyrene-based redox catalyst, with an electron-transfer cycle, in which the resulting triplet is reductively quenched and  ...[more]

Similar Datasets

| S-EPMC5676201 | biostudies-literature
| S-EPMC10034082 | biostudies-literature
| S-EPMC4406487 | biostudies-literature
| S-EPMC11290444 | biostudies-literature
| S-EPMC9557244 | biostudies-literature
| S-EPMC4882737 | biostudies-other
| S-EPMC7607533 | biostudies-literature
| S-EPMC8252614 | biostudies-literature
| S-EPMC8809420 | biostudies-literature
| S-EPMC5994792 | biostudies-literature