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...

In this laboratory exercise we will measure a chemical equilibrium constant using key proton signals in a Nuclear Magnetic Resonance (NMR) spectrum. Those doing the “traditional” P Chem experiments will examine a keto-enol tautomerism, while those doing the “biophysical” experiments will look at the cis-trans equilibrium for a peptide bond. In each case, the relative concentration of the equili...

The asymmetric unit of the title compound, C(10)H(10)N(2)O, contains two crystallographically independent mol-ecules with similar geometries, which exist in the keto form. The C=O bond lengths are 1.2878 (12) Å in mol-ecule A and 1.2890 (12) Å in mol-ecule B, indicating that the compound undergoes enol-to-keto tautomerism during the crystallization process. In mol-ecule A, the pyrazole ring is ...

Fapy-adenine, Fapy-guanine, Tautomerism, Solvent Effect The results of theoretical geometry prediction of formamidopyrimidine(fapy)-adenine and fapy-guanine tautomers are presented. Among 54 potential tautomeric structures of fapyadenine the most stable structure corresponds to the diamino-keto isomer. The solvent effect has insignificant influence on the fapy-adenine tautomers succession. The ...

Palladium (II) coordination complexes catalyze the reaction of alcohols with ketones to yield ethers. During the catalytic cycle, the alcohol adds selectively to the β-carbon (anti-Markovnikov). In this work, mechanism and kinetics for the reaction of methanol with methyl vinyl ketone (MVK), being catalyzed by Pd, has been theoretically investigated in detail. Using quantum mechanical approach,...

The formation of keto-enamine based crystalline, porous polymers in water is investigated for the first time. Facile access to the Schiff base reaction in water has been exploited to synthesize stable porous structures using the principles of Dynamic Covalent Chemistry (DCC). Most credibly, the water-based Covalent Organic Frameworks (COFs) possess chemical as well as physical properties such a...

palladium (ii) coordination complexes catalyze the reaction of alcohols with ketones to yield ethers. during the catalytic cycle, the alcohol adds selectively to the β-carbon (anti-markovnikov). in this work, mechanism and kinetics for the reaction of methanol with methyl vinyl ketone (mvk), being catalyzed by pd, has been theoretically investigated in detail. using quantum mechanical approach,...