Photoinduced processes in macrocyclic isoalloxazine-anthracene systems

Two new macrocyclic structures containing 8-hidroxyisoalloxazine and 1,5-dihydroxyanthracene moieties linked by aliphatic chains of different lengths (n = 4 and 6) were designed and synthesized in order to study photoinduced electron transfer (PET) processes from the anthracene unit towards the isoalloxazine singlet excited state induced by structural changes due to different intrachromophoric distances and orientations. The compounds have been fully characterized by NMR spectroscopy and the X-ray solid state structures of both macrocycles have been elucidated. Photophysical measurements, including continuous wavelength photoinduced absorption (cw-PIA), at room temperature and 77 K have been carried out in order to investigate the influence of the close contacts between the aromatic groups (?-? stacking) on the photophysical properties of the macrocycles.