Table 1: DFT/B3LYP (3-21G) parameters over all proposed tautomers
(12-18 and 21A-C).
The protonation states and the tautomers
, when possible, were adjusted according to pH 7.4 .
As shown in Table 2, the bands at 1746-1750 [cm.sup.-1] for the free ligands were assigned to the C=O stretching vibration of [beta]-diketonate and the bands at 1742-1746 [cm.sup.-1] for the corresponding complexes; there is hardly any red shifts to form enol tautomers
in complexes [7, 20-22], which confirmed that oxygen atoms of carbonyl group of [beta]-diketonate did not bind to uranyl ion.
The structure of nemorosone ([C.sub.33][H.sub.42][O.sub.4]) is a mixture of tautomers
: l-benzoyl-4-hydroxy-8,8-dimethyl-3,5,7tris(3-methyl-2-butenyl)-bicyclo-[3.3.1]-non-3-ene- 2,9-dione and 1-benzoyl-2-hydroxy-8,8-dimethyl-3,5,7-tris(3-methyl-2-butenyl)-bicyclo-[3.3.1]-non-2-ene-4,9-dione.
The ratios were determined through NMR spectroscopic studies by measuring the integral ratios of the CH=N sharp singlets in the solvents reported and the attribution to the two tautomers
of the different groups of signals was done upon COSY experiments.
Alparone, "Theoretical study on the static and dynamic firstorder hyperpolarizabilities of adenine tautomers
," Molecular Physics, 2013.
In cases where candidate structures were ambiguous, alternative charged forms or tautomers
were tested as well as the original database entry.
The crystal structure of [HL.sup.1] has been reported in literature  but was redetermined to investigate if the new method of crystal isolation could affect the R-factor which was earlier reported as 0.0542 , and control the intramolecular rearrangement of the molecule from structure (4) to any of the other tautomers
, see Figure 1.
Bonda has been teaching the industry about the instability of this and other ingredients for decades, but in this presentation, he focused on diketo tautomers
and diketo triplets and the role they play in the production of singlet oxygen, which is toxic to cells.
Obayes et al., "Thermodynamic studies on 4-aminocoumarin tautomers
," International Journal of Electrochemical Science, vol.
THEORETICAL STUDY OF TWO TAUTOMERS
OF LOSARTAN IN GAS PHASE AND AQUEOUS SOLUTION.
The [alpha]-keto acid spontaneously cyclizes to form enamine/imine tautomers
; but at the naturally acidic pH of ink, the [alpha]-keto acid dominates.