Synthesis, structure and properties of spin-labeled photosensitive chromone derivative

A new hybrid chromone derivative bearing α-bromofuryl, p-(iminomethyl)benzoyl and 2,2,6,6-tetramethylpiperidin-1- oxyl moieties was synthesized by the azomethine reaction involving 4-amino-TEMPO. The benzoyl moiety in this paramagnetic molecule is almost perpendicular to the chromone plane. Having been exposed to UV light, this paramagnet undergoes a transformation accompanied by appearance of intense absorption and luminescence bands with maxima at 420 and 500 nm, respectively, i.e., the presence of paramagnetic moiety does not interfere with generation of fluorescence.