Hansen, Poul Erik; Vakili, Mohammad; Kamounah, Fadhil S.; Spanget-Larsen, Jens published their research in Molecules in 2021. The article was titled 《NH Stretching Frequencies of Intramolecularly Hydrogen-Bonded Systems: An Experimental and Theoretical Study》.Application of 609-14-3 The article contains the following contents:
The vibrational NH stretching transitions in secondary amines with intramol. NH···O hydrogen bonds were investigated by exptl. and theor. methods, considering a large number of compounds and covering a wide range of stretching wavenumbers. The assignment of the NH stretching transitions in the exptl. IR spectra was, in several instances, supported by measurement of the corresponding ND wavenumbers and by correlation with the observed NH proton chem. shifts. The observed wavenumbers were correlated with theor. wavenumbers predicted with B3LYP d. functional theory, using the basis sets 6-311++G(d,p) and 6-31G(d) and considering the harmonic as well as the anharmonic VPT2 approximation Excellent correlations were established between observed wavenumbers and calculated harmonic values. However, the correlations were non-linear, in contrast to the results of previous investigations of the corresponding OH···O systems. The anharmonic VPT2 wavenumbers were found to be linearly related to the corresponding harmonic values. The results provide correlation equations for the prediction of NH stretching bands on the basis of standard B3LYP/6-311++G(d,p) and B3LYP/6-31G(d) harmonic analyses, with standard deviations close to 38 cm-1. This is significant because the full anharmonic VPT2 anal. tends to be impractical for large mols., requiring orders of magnitude more computing time than the harmonic anal. The experimental part of the paper was very detailed, including the reaction process of Ethyl 2-methyl-3-oxobutanoate(cas: 609-14-3Application of 609-14-3)
Ethyl 2-methyl-3-oxobutanoate(cas: 609-14-3) belongs to ketone compounds. Ketones are highly reactive, although less so than aldehydes, to which they are closely related. Much of their chemical activity results from the nature of the carbonyl group. Ketones readily undergo a wide variety of chemical reactions.Application of 609-14-3
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