Can chemist bottle sunlight? In the continuing search for energy that does not rely on fossil
fuels solar energy remains a key focus. An active area of research in the solar energy field
is in molecular solar thermal (MOST) energy storage. A MOST system absorbs UV light
and stores it for release on demand at a later time. A MOST molecule absorbs sunlight and
transforms it into a high energy isomer that traps energy in its chemical bonds. Then a trigger
is used to revert it to its original state, and this process releases heat.
A recent Science article reports an advance in renewable-energy chemistry. Researchers at
UC Santa Barbara and UCLA have engineered a pyrimidone-based MOST molecule that
can store sunlight for up to three years. What is remarkable about this molecule is that it is
water-soluble and stores 1.65 MJ/kg of stored energy, the most of any MOST compound
to date. This is more than a lithium-ion battery. The new compound, when triggered by an
acid catalyst, released enough energy to boil approximately a half milliliter of water in
half a second.
This MOST system was inspired by the structure of DNA whose bases absorb UV light and
form pyrimidones. The researchers engineered a new molecule by adding methyl groups to
the hexagonal ring of one of these pyrimidones. The UV light is absorbed by the molecule
and creates a new bond that forms two square units from the hexagon. When acid is used to
break the bond, the isomer returns to the original shape and releases heat. The isomer that is
created is called a Dewar-photoisomer, and its bonds are highly strained which allows it to
store a large amount of energy. The system can be recharged with light and can be reused
over and over again. The scientific community is excited about this advance because it
appears scalable and is easy to synthesize. The water solubility opens up new possibilities
for its uses. One drawback is that it takes a long time to charge, so extensions of the
research should focus on charging it more rapidly.
Articles used: https://cen.acs.org/energy/solar-power/Engineered-molecule-stashes-enough-
sunlight/104/web/2026/02 https://www.science.org/doi/10.1126/science.aec6413
Your title is very good and should attract a readers attention. I think it is wise to focus the lede paragraph on the MOST phenomenon since the general reader would find that to be news itself, although the original article is about the particular pyrimidone and it's special effectiveness as a MOST molecule. Your explanation is quite good. I think a general reader might get the essence of the idea even if they don't have a clear idea of what an isomer is. Note that diagrams of pyrimidone and the dewar photo isomer are available (https://www.pnas.org/doi/10.1073/pnas.080057097). Your figures are quit good but could probably use captions. It took me a bit to figure out the second one. You might be a little more specific about the fact that it is an 0.5 ml solution of the pyrimidone that comes to a boil in half a second. C&E News is a publication for Chemists and Engineers. Science is really a scientific journal that reaches quite a wide audience, but mostly a scientifically sophisticated audience. Overall quite an effective piece on a very interesting topic showcasing the power of modern chemistry.
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