Gustavsson, Thomas published the artcileSinglet Excited-State Behavior of Uracil and Thymine in Aqueous Solution: A Combined Experimental and Computational Study of 11 Uracil Derivatives, Recommanded Product: 3-Methylpyrimidine-2,4(1H,3H)-dione, the publication is Journal of the American Chemical Society (2006), 128(2), 607-619, database is CAplus and MEDLINE.
The excited-state properties of uracil, thymine, and nine other derivatives of uracil have been studied by steady-state and time-resolved spectroscopy. The excited-state lifetimes were measured using femtosecond fluorescence upconversion in the UV. The absorption and emission spectra of five representative compounds have been computed at the TD-DFT level, using the PBE0 exchange-correlation functional for ground- and excited-state geometry optimization and the polarizable continuum model (PCM) to simulate the aqueous solution The calculated spectra are in good agreement with the exptl. ones. Experiments show that the excited-state lifetimes of all the compounds examined are dominated by an ultrafast (< 100 fs) component. Only 5-substituted compounds show more complex behavior than uracil, exhibiting longer excited-state lifetimes and biexponential fluorescence decays. The S0/S1 conical intersection, located at CASSCF (8/8) level, is indeed characterized by pyramidalization and out of plane motion of the substituents on the C5 atom. A thorough anal. of the excited-state potential energy surfaces, performed at the PCM/TD-DFT(PBE0) level in aqueous solution, shows that the energy barrier separating the local S1 min. from the conical intersection increases going from uracil through thymine to 5-fluorouracil, in agreement with the ordering of the exptl. excited-state lifetime.
Journal of the American Chemical Society published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, Recommanded Product: 3-Methylpyrimidine-2,4(1H,3H)-dione.
Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia