Experimental and theoretical investigation of the IR spectra and thermochemistry of four isomers of 2-N,N-dimethylaminecyclohexyl 1-N',N'-dimethylcarbamate

Abstract

Abstract:A combined experimental and Density functional theory (DFT) B3LYP/6-311+G* study on the IR spectra of four stable isomers of 2-N,N-dimethylaminecyclohexyl 1-N',N'-dimethylcarbamate was performed. Our theoretical calculations reveal that two new isomers of this compound exist and may be more stable than the known isomers. In addition the entropy, heat capacity, and the enthalpy content of the stable isomers are computed by fitting the calculated data to a standard Shomate equation and IR spectra for the two new isomers are presented.

Assessing the Utility of Infrared Spectroscopy as a Structural Diagnostic Tool for β-Sheets in Self-Assembling Aromatic Peptide Amphiphiles

“…Additionally, we have previously observed the absence of the 1690 cm –1 peak, in hydrogels assembled from non-Fmoc aromatic dipeptides that lack the carbamate group. The carbamate group is known to absorb IR light in the 1685–1730 cm –1 range, − including a report by Nuansing et al on Fmoc-FG powders, significantly higher than the 1650 cm –1 absorption for free amide groups. For these reasons, it is important to assess the diagnostic value of the amide I infrared region for these systems.…”

Structural and theoretical studies of 4,4'-[1,4-phenylene-bis-(azanediyl)]dipent-3-en-2-one: evidence of a π-delocalized keto-enamine

“…To the best of our knowledge limited information on these data points are available for the compounds investigated herein. The B3LYP/6-31G* basis set has been shown to adequately reproduce vibrational frequencies for large scale systems to a reasonably good level of approximation 9,[17][18][19] . We attempted a test calculation at the B3LYP/6-311++G** level of theory and as a result the differences in energies and vibrational frequencies for the 3b/3f separation are minimal.…”