The role of symmetric functionalisation on photoisomerisation of a UV commercial chemical filter

Photoisomerisation has been shown to be an efficient excited-state relaxation mechanism for a variety of nature-based and artificial-based molecular systems. Here we report on the excited-state relaxation dynamics and consequent photostability of a symmetrically functionalised cinnamate by transient electronic absorption spectroscopy, along with complementary computational and steady-state spectroscopy methods. The findings are then discussed in comparison to 2-ethylhexyl- E -4-methoxycinnamate, a structurally related 'off the shelf' chemical filter present in commercial sunscreens with a similar absorption profile. The present study allows for a like-for-like comparison beween 2-ethylhexyl- E -4-methoxycinnamate and the functionalised cinnamate, driven by the need to enhance solar protection across both the UVA and UVB regions of the electromagnetic spectrum. Photoisomerisation has been shown to be an efficient excited-state relaxation mechanism for a variety of nature-based and artificial-based molecular systems.