  When irradiated with violet light, hexaazatrinaphthylene (HATN) extracts a
hydrogen atom from an alcohol forming a long-living hydrogenated species. The
apparent kinetic isotope effect for fluorescence decay time in deuterated
methanol (1.56) indicates that the lowest singlet excited state of the molecule
is a precursor for intermolecular hydrogen transfer. The photochemical
hydrogenation occurs in several alcohols (methanol, ethanol, isopropanol) but
not in water. Hydrogenated HATN can be detected optically by an absorption band
at 1.78 eV as well as with EPR and NMR techniques. Mass spectroscopy of
photoproducts reveal di-hydrogenated HATN structures along with methoxylated
and methylated HATN molecules which are generated through the reaction with
methoxy radicals (remnants from alcohol splitting). Experimental findings are
consistent with the theoretical results which predicted that for the excited
state of the HATN-solvent molecular complex, there exists a barrierless
hydrogen transfer from methanol but a small barrier for the similar oxidation
of water.
