Quantifying soft degrees of freedom in volatile organic compounds: insight from quantum chemistry and focused single molecule experiments

Abstract

Sampling the vast conformational landscape of organic compounds remains a challenging task in computational chemistry, especially when it comes to the characterization of soft-degrees of freedom and relatively small energy...

Quantifying Conformational Isomerism in Chain Molecules by Linear Raman Spectroscopy: The Case of Methyl Esters

“…The effect of the ester group is very prominent: the adjacent C C α bond is much more flexible than the purely alkyl one. This effect is nullified if the alkanoate part of the ester is branched at the α position, which was shown in a recent microwave study on ethyl 2-methylpentanoate [41]. There, the observed minimum structure has a O C C α C β angle of 143.1°, which can be described as a slightly tilted ttt structure in our nomenclature.…”

“…Reference values for ∆E el on B3LYP/6-31G(d) level [6] and ∆E 0 on B2PLYP-D3BJ/aug-cc-pVTZ level [9] added for comparison. study on ethyl 2-methylpentanoate [41]. There, the observed minimum structure has a O C C α C β angle of 143.1°, which can be described like a slightly tilted ttt structure in our nomenclature.…”

Quantifying Conformational Isomerism in Chain Molecules by Linear Raman Spectroscopy: The Case of Methyl Esters

“…more flexible than the purely alkyl one. This effect is nullified if the alkanoate part 590 of the ester is branched at the α position, which was shown in a recent microwave 591 study on ethyl 2-methylpentanoate[36]. There, the observed minimum structure has a592 O C C α C β angle of 143.1°, which can be described like a slightly tilted ttt structure in 593 our nomenclature.…”

Benchmarking quantum chemical methods for accurate gas-phase structure predictions of carbonyl compounds: the case of ethyl butyrate

“…Within the studies of small to medium sized molecules (up to 30 heavy atoms), rotational spectroscopy has long manifested itself as the method of choice to characterize the structure and dynamics of isolated systems [10][11][12]. Hereby, insight from quantum chemistry as a complementary tool is required to efficiently assign the experimental data and, at the same time, provide highly accurate sets of experimental constants that can be used in return to benchmark quantum chemical methodologies [11,13,14]. The development of theoretical methods has long been focused on providing accurate characterization of molecular structure and non-covalent interactions [15].…”