A model is presented for the prediction of OH stretching fundamental wavenumbers of alcohol conformers in the gas phase by application of a small set of empirical anharmonicity corrections to...

By a combination of linear FTIR and Raman jet spectroscopy, racemic trans-1,2-cyclohexanediol is shown to form an energetically unrivalled S 4 -symmetric heterochiral dimer in close analogy to 1,2-ethanediol.Analogous experiments with enantiopure trans-1,2-cyclohexanediol reveal the spectral signature of at least three unsymmetric homochiral dimers. A comparison to signal-enhanced spectra of 1,2-ethanediol and to calculations uncovers at least three transiently homochiral dimer contributions as well. In few of these dimer structures, the intramolecular OHÁ Á ÁO contact present in monomeric 1,2-diols survives, despite the kinetic control in supersonic jet expansions. This provides further insights into the dimerisation mechanism of conformationally semi-flexible molecules in supersonic jets. Racemisation upon dimerisation is shown to be largely quenched under jet cooling conditions, whereas it should be strongly energy-driven at higher temperatures. The pronounced energetic preference for heterochiral aggregation of vicinal diols is also discussed in the context of chirality-induced spin selectivity. † Electronic supplementary information (ESI) available: Interactive and static structures, tables of experimental and computational details, energy diagrams for different levels of calculation, and additional experimental spectra. See

A combination of linear infrared and Raman spectroscopy in supersonic slit jet expansions is used to clarify the conformational preferences in the dimer of the transiently chiral benzyl alcohol (phenylmethanol)...

Molecular aggregation is of paramount importance in many chemical processes, including those in living beings. Thus, characterization of the intermolecular interactions is an important step on its understanding. We describe...

Complexes of t-butyl alcohol with norbornene and its monocyclic constituents cyclopentene and cyclohexene are studied via their OH stretching fundamental transitions in supersonic jet expansions. Compared to OH···OH hydrogen bonds, the spectral shifts due to OH···π bonding in the mixed dimers are reduced by a factor of 2. Mixed trimers show substantially different spectral signatures due to cooperative effects. Regioselective docking on the two sides of the double bond in norbornene is observed. Harmonic modeling of the spectra using dispersion-corrected hybrid functionals is quite successful, suggesting a high predictive power for this poorly explored class of complexes between alcohols and alkenes.

Models for the quick estimation of energy splittings caused by coherent tunneling of hydrogen atoms are evaluated with available experimental data for alcohols and improvements are proposed. The discussed models...

Chirality recognition between largely rigid molecules can be applied as ab enchmark for the description of intermolecular forces by theoretical methods,b ecause one constituent is merely mirrored, so other deficits of the methods such as neglect of anharmonicity should mostly cancel. To test this approach, mixed OH···p-bridged dimers between the enantiomers of the bicyclic monoterpene a-pinene and the chiral secondary alcohols borneol, a-fenchol, isopinocampheol, and 1-phenylethanol were formed in as upersonic jet and probed by linear FTIR spectroscopy. With borneol and afenchol, pronounced shifts in the hydroxyl stretching frequencies upon exchange of the handedness are observed. From three tested density functionals,only B3LYP-D3(BJ) is able to predict these diastereomeric shifts in as atisfactory manner, while M06-2X and wB97X-D fall short.Chirality recognition, the ability of chiral objects to distin-Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Rotational microwave jet spectroscopy studies of the monoterpenol α-fenchol have so far failed to identify its second most stable torsional conformer, despite computational predictions that it is only very slightly higher in energy than the global minimum. Vibrational FTIR and Raman jet spectroscopy investigations reveal unusually complex OH and OD stretching spectra compared to other alcohols. Via modeling of the torsional states, observed spectral splittings are explained by delocalization of the hydroxy hydrogen atom through quantum tunneling between the two non-equivalent but accidentally near-degenerate conformers separated by a low and narrow barrier. The energy differences between the torsional states are determined to be only 16(1) and 7(1) cm−1hc for the protiated and deuterated alcohol, respectively, which further shrink to 9(1) and 3(1) cm−1hc upon OH or OD stretch excitation. Comparisons are made with the more strongly asymmetric monoterpenols borneol and isopinocampheol as well as with the symmetric, rapidly tunneling propargyl alcohol. In addition, the third—in contrast localized—torsional conformer and the most stable dimer are assigned for α-fenchol, as well as the two most stable dimers for propargyl alcohol.