['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', ']', '.']