Phenol transformation and dimerisation, photosensitised by the triplet state of 1-nitronaphthalene: A possible pathway to humic-like substances (HULIS) in atmospheric waters

► The triplet state of 1-nitronaphthalene oxidises phenol to phenoxyl radical. ► Dimerisation of phenoxyl yields dihydroxybiphenyls and phenoxyphenols. ► Photoprocessed material had fluorescence properties analogous to HULIS. ► The same material had photosensitising properties (1O2 photoproduction). ► Fluorescence excitation-emission matrix is very useful to study such systems.