Etinski, Mihajlo’s team published research in Physical Chemistry Chemical Physics in 12 | CAS: 608-34-4

Etinski, Mihajlo published the artcileAb initio investigation of the methylation and hydration effects on the electronic spectra of uracil and thymine, Product Details of C5H6N2O2, the publication is Physical Chemistry Chemical Physics (2010), 12(19), 4915-4923, database is CAplus and MEDLINE.

In this work, we investigated the lowest-lying electronic excitations for a series of methyl-substituted uracil derivatives, i.e., uracil, 1-methyluracil, 3-methyluracil, thymine, 1-methylthymine, 1,3-dimethyluracil, 3-methylthymine, 1,3-dimethylthymine, and their microhydrated complexes by means of coupled cluster singles and approx. doubles (CC2) and d. functional theory (DFT) methods. The bulk water environment was mimicked by a combination of microhydration and the conductor-like screening model (COSMO). We find that the shift of the electronic excitation energies due to methylation and hydration depend on the character of the wave function and on the position of the Me substituent. The lowest-lying singlet and triplet n → π^* states are insensitive to methylation but are strongly blue-shifted by microhydration and bulk water solvation. The largest red-shift of the first ¹(π → π^*) excitation occurs upon methylation at N₁ followed by substitution at C₅ whereas no effect is obtained for a methylation at N₃. For this state, the effects of methylation and hydrogen bonding partially cancel. Upon microhydration with six water mols., the order of the ¹(n → π^*) and ¹(π → π^*) states is reversed in the vertical spectrum. Electrostatic solute-solvent interaction in bulk water leads to a further increase of their energy separation The n → π^* states are important intermediates for the triplet formation. Shifting them energetically above the primarily excited ¹(π → π^*) state will considerably decrease the triplet quantum yield and thus increase the photostability of the compounds, in agreement with exptl. observations.

Physical Chemistry Chemical Physics 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, Product Details of C5H6N2O2.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia