The furan microsolvation blind challenge for quantum chemical methods: First steps

Abstract

Herein we present the results of a blind challenge to quantum chemical methods in the calculation of dimerization preferences in the low temperature gas phase. The target of study was the first step of the microsolvation of furan, 2-methylfuran and 2,5-dimethylfuran with methanol. The dimers were investigated through IR spectroscopy of a supersonic jet expansion. From the measured bands, it was possible to identify a persistent hydrogen bonding OH–O motif in the predominant species. From the presence of another band, which can be attributed to an OH-π interaction, we were able to assert that the energy gap between the two types of dimers should be less than or close to 1 kJ/mol across the series. These values served as a first evaluation ruler for the 12 entries featured in the challenge. A tentative stricter evaluation of the challenge results is also carried out, combining theoretical and experimental results in order to define a smaller error bar. The process was carried out in a double-blind fashion, with both theory and experimental groups unaware of the results on the other side, with the exception of the 2,5-dimethylfuran system which was featured in an earlier publication.

Three-dimensional docking of alcohols to ketones: an experimental benchmark based on acetophenone solvation energy balances

“…This is very valuable because anharmonic zero-point energy corrections are difficult to compute robustly for supramolecular systems of this size. 9 We nevertheless include harmonic zero-point correction in our analysis, but we point out the similarity to electronic energy predictions. The docking preference is determined by the interaction of R with R 0 in comparison to Ph with R 0 (Fig.…”

“…It has been found in previous work that T c is typically on the order of 150 K or less for molecular complexes, if the conformational interconversion barrier is in the 1 to 5 kJ mol À1 energy range and sufficiently narrow. 6,8,9 The concept of intermolecular balances is most easily applied to 1 : 1 complexes between a solute and a solvent. While cooperativity is important for hydrogen-bonded solvents, 1 : n complexes would introduce too many isomers for a straightforward Boltzmann analysis.…”

Intermolecular dissociation energies of hydrogen-bonded 1-naphthol complexes

“…Analogous methanol·furan and methanol·2,5-DMF complexes have been investigated by IR spectroscopy in slit supersonic jets, with a focus on the relative energies of the OH· · ·O and OH· · · π forms, also termed an "intermolecular energy balance". [56][57][58] Here, we provide the absolute dissociation energy, albeit with 1-naphthol replacing methanol as an H-bond donor. Finally, we compare the experimental D 0 values to those calculated with the widely-used dispersion-corrected density functional theory (DFT) methods B3LYP-D3, B97-D3 and ωB97X-D. [8][9][10][11]59 II.…”

Challenging the Molecular Parameters of Vetiver: Can 4,5‐Dimethyl‐3‐(3′‐methylbut‐1′‐en‐2′‐yl)‐4‐phenylcyclopent‐2‐en‐1‐one Mimic Zizaenones in Structure and Odor?

“…Thereby, it should be possible to compensate the steric repulsion of the C-3 and C-4 substituents as apparent for branched alkyl groups. [14][15][16][17][18] The effect becomes all the more important when large molecular systems are treated, which makes the right choice of quantum chemical method crucial to obtain realistic structural insight into the investigated system. The precise quantification of weak interand intramolecular London dispersion forces at quantum chemical level is not trivial, and its proper description is still a topic of active research.…”