document: Alternatively to H-atom photodetachment from the intermediate radicals, the latter may serve as reducing agents. Evidence has been reported in recent years that the pyridinyl radical (PyH) is an exceptionally strong reducing agent which can even reduce CO2 to formaldehyde, formic acid or methanol with suitable catalyzers [27–29], albeit the mechanisms of these reactions are currently poorly understood [30–32]. The theoretically predicted dissociation thresholds of the AcH, AOH and BAH radicals are about 2.7eV, 2.5eV and 3.0eV, respectively (see Fig. 4), while the predicted dissociation threshold of the pyridinyl radical is much lower, about 1.7eV [1]. Pyridinyl is thus a significantly stronger reductant than acridinyl and related radicals. It is therefore not expected that the latter will be able to reduce carbon dioxide in dark reactions.
extractive_keyphrases: acridinyl carbon dioxide catalyzers co2 formaldehyde formic acid intermediate radicals methanol pyh pyridinyl radicals reducing agent reducing agents reductant
abstractive_keyphrases: ach, aoh and bah radicals h-atom photodetachment pyridinyl radical reduce carbon dioxide in dark reactions