Hydrogen Bonding in the Dimer and Monohydrate of 2-Adamantanol: A Test Case for Dispersion-Corrected Density Functional Methods

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 8; p. 2584
• Main Authors: Juanes, Marcos, Saragi, Rizalina Tama, Pérez, Cristóbal, Evangelisti, Luca, Enríquez, Lourdes, Jaraíz, Martín, Lesarri, Alberto
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 17.04.2022; MDPI
• Subjects: Adamantane - analogs & derivatives; Alcohol; Alcohols; Approximation; Broadband; chiral recognition; Computer applications; Density functional theory; Dispersion; Electron density; Hydration; Hydrogen Bonding; Hydrogen bonds; Isomers; jet spectroscopy; Molecular Conformation; Molecular orbitals; non-covalent interactions; Phenols; Polymers; Potential energy; rotational spectroscopy; Spectroscopy; Spectrum analysis; Symmetry; transient chirality; hydrogen bonding; chiral recognition; transient chirality; non-covalent interactions; rotational spectroscopy; jet spectroscopy
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27082584

Weakly-bound intermolecular clusters constitute reductionist physical models for non-covalent interactions. Here we report the observation of the monomer, the dimer and the monohydrate of 2-adamantanol, a secondary alcohol with a bulky ten-carbon aliphatic skeleton. The molecular species were generated in a supersonic jet expansion and characterized using broadband chirped-pulse microwave spectroscopy in the 2-8 GHz frequency region. Two different - O-H···O hydrogen-bonded isomers were observed for the dimer of 2-adamantanol, while a single isomer was observed for the monomer and the monohydrate. The experimental rotational parameters were compared with molecular orbital calculations using density functional theory (B3LYP-D3(BJ), B2PLYP-D3(BJ), CAM-B3LYP-D3(BJ), ωB97XD), additionally providing energetic and electron density characterization. The shallow potential energy surface makes the dimer an interesting case study to benchmark dispersion-corrected computational methods and conformational search procedures.