Photophysics and photodimerization of 6,5′-dimethylangelicin in different solvents

The 6,5′-DMA photodimerization was investigated in different solvents and in different experimental conditions. Two pyrone-pyrone and one furan-pyrone photodimers of 6,5′-DMA were the main photoproducts detected in the irradiated solution. The effects of the 6,5′-DMA concentration and of oxygen on the amounts of the dimers obtained together with the photophysical behaviour gave indications on the formation mechanism of different dimers.