The photoelectron spectrum (PES) of the uracil anion is reported and discussed from the perspective of quantum chemical calculations of the vertical detachment energies (VDEs) of the anions of various tautomers of uracil. The PES peak maximum is found at an electron binding energy of 2.4 eV, and the width of the main feature suggests that the parent anions are in a valence rather than a dipole-...

We study spectral hole burning in the unstable tautomer form of free-base Br-tetraethylporphyrin in poly(vinyl butyral) "lm, which is created by photo-transformation of the stable tautomer form at low temperature.We report a Debye}Waller factor a"0.7 at 4 K, burning quantum e$ciency u&10~3 and thermal stability up to 115 K for this system. We observe for the "rst time that narrow-band illuminat...

The tautomerism of curcumin has been investigated in ethanol/water binary mixtures by using UV-Vis spectroscopy and advanced quantum-chemical calculations. The spectral changes were processed by using advanced chemometric procedure, based on resolution of overlapping bands technique. As a result, molar fractions of the tautomers and their individual spectra have been estimated. It has been show...

Relative tautomerization energies, dipole moments and polarizabilities for the tautomers of (R)-4-amino-1,2oxazolidin-3-one (Cycloserine) was studied by quantum-chemical calculations, using the HF and DFT(B3LYP) level of theory with the 6-311++G(d,p) basis set in the gas phase and different solvents using SCRF model, with full geometry optimization. Entropies, enthalpies, Gibbs free energies an...

We explore tautomerism and its consequences in the first example of diamino-benzoquinonediimine bearing both electron-donating electron-withdrawing groups on same 6-? electron subunit.

The title compound, C(15)H(12)N(2)OS, exists as the thione tautomer in the solid state. The phenyl group is almost perpendicular [dihedral angle = 87.96 (5)°] to the fused ring system (r.m.s. deviation = 0.036 Å for 13 ring and exocyclic non-H atoms). In the crystal, centrosymmetric dimers, sustained by pairs of N-H⋯S hydrogen bonds, are connected into layers parallel to (-101) by C-H⋯O and C-H...

Earlier steady-state fluorescence studies showed that 2-butylamino-6-methyl-4-nitropyridine N-oxide (2B6M) can undergo fast excited-state intramolecular proton transfer (ESIPT). In a nonpolar solvent such as n-octane, both normal and tautomeric fluorescence was observed. Strikingly, the relative ratio of those two emission bands and the fluorescence quantum yield of the normal emission were fou...