Determination of Equilibrium Constants using NMR Spectrscopy
ثبت نشده
چکیده
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 equilibrium species can be determined from the NMR signal strength. The relative concentrations can then be leveraged to determine the desired equilibrium constant. Solvent effects on the equilibrium constant will be examined.
منابع مشابه
Determination of Equilibrium Constants using NMR Spectrscopy
In this laboratory exercise we will measure the Equilibrium Constant Kc for the keto-enol tautomerism of two -diketones and two -diketoesters. This will be accomplished by measuring the signal strength of key protons in the Nuclear Magnetic Resonance (NMR) spectrum of the equilibrium system. The influence of the solvent on the equilibrium position will be examined by considering the measured ...
متن کاملAb initio and DFT studies on tautomerism of 5-methyl cytosine in gaseous phase
Ab initio and DFT methods have been used to study the seven tautomeric forms of 5-methylcytosine molecule.The related tautomer in gas phase have been studied at HF/6-31G, HF/6-31G* and B3LYP/6-31G* levels oftheory. The structures,enthalpies,entropies,Gibbs free energies,relative tautomerization energies of tautomersand tautomeric equilibrium constants were compared and analyzed along with full ...
متن کاملStudy of protonation equilibrium of lorazepam by potentiometry and multiwavelengths spectrophotometry
The acid-base equilibrium of lorazepam was studied by means of potentiometry andmultiwavelengths spectrophotometry. The stoichiometric equilibrium constants were determinedat 25 °C and constant ionic strength 0.1 mol L-1 (NaCl). The acidity constants pK1=1.58±0.05and pK2=11.67±0.07 were found by potentiometry, and pK1=1.54±0.02 and pK2=11.61±0.03 bymulti-wavelengths spectrophotometry. Potentiom...
متن کامل31P NMR Studies of the Arginine Kinase Reaction EQUILIBRIUM CONSTANTS AND EXCHANGE RATES AT STOICHIOMETRIC
The arginine kinase reaction, the reversible transfer of the terminal phosphoryl group of ATP to L-arginine, has been investigated by the technique of 31P NMR at catalytic and stoichiometric concentrations of the enzyme. Three of the four substrates, ATP, ADP, and P-arginine produce easily distinguishable resonances in the 31P NMR spectrum, thus permitting a determination of equilibrium constan...
متن کاملDetermination of Equilibrium Constants using NMR Spectroscopy
In this laboratory exercise we will measure the equilibrium constant for the cis-trans isomerism about a peptide bond involving the amino acid L-Proline. This will be accomplished by determining the relative concentrations of each isomer using key proton signals in a Nuclear Magnetic Resonance (NMR) spectrum of a solution of an N-Acetyl derivative of the amino acid, which will serve as a model ...
متن کامل