Microhydrated 3‐Methyl‐3‐oxetanemethanol: Evolution of the Hydrogen‐Bonding Network from Chains to Cubes

Abstract

Broadband rotational spectroscopy is used to investigate the geometries of 3-methyl-3-oxetanemethanol and its complexes with up to six water molecules, which are produced in supersonic jets. The main lowenergy isomers of these clusters are unambiguously identified in the spectra with the support of quantumchemical calculations. The conformation of the 3-methyl-3-oxetanemethanol geometry is found to be influenced by the microsolvation effects. The hydrogen-bond arrangements in the hydrate complexes, which are governed by the water-water and water-solute interactions, exhibit characteristic configurations with increasing number of water molecules and resemble the main isomers of the corresponding pure water clusters. Evolution of the hydrogen-bonding structures from onedimensional chains to two-dimensional rings and further to multicyclic three-dimensional networks is observed, which provides information about the build-up process.

Wetting vs Droplet Aggregation: A Broadband Rotational Spectroscopic Study of 3‐Methylcatechol⋅⋅⋅Water Clusters

“…Overall, the MC hydrates in the wetting pathway exhibit substantial solvation of the whole MC molecule as highlighted by the green "blanket" of attractive interaction over the aromatic ring in the NCI plots, whereas those in the droplet pathway show water droplet formation driven by the hydrogen-bonding interactions among the OH groups of water and MC, with little to no interactions between the aromatic ring and water molecules. Similar to the previous studies, [6,7,[25][26][27] the MC hydrates in the droplet pathway contain water aggregates that show similarity to pure water clusters although with one OH of water replaced by that of MC, with the 3D water-cluster like structure emerging in the MC pentahydrate (Figure 2). In contrast, the experimentally observed MC hydrates in the wetting pathway have drastically different water arrangements, emphasizing solvation of the aromatic face of MC.…”

Evolution of Solute–Water Interactions in the Benzaldehyde-(H2O)1–6 Clusters by Rotational Spectroscopy

“…Microwave spectroscopy has also been applied to solute–water clusters. Due to the low number density of clusters in the molecular beam, there are very few studies with rotational resolution of solute-(H 2 O) n clusters involving more than four water molecules. ,− Regarding hydrated aromatic compound clusters, which are of biological and astronomical importance, up to four water molecules have been reported in the study of acenaphthene-(H 2 O) 1–4 …”

Wetting vs Droplet Aggregation: A Broadband Rotational Spectroscopic Study of 3‐Methylcatechol⋅⋅⋅Water Clusters

“…The advent of chirp pulsed Fourier transform microwave (CP‐FTMW) spectroscopy has provided a powerful tool to investigate the early phases of solvation by allowing one to easily and unambiguously track the sequential solvation one water molecule at a time. One recent highlight is the CP‐FTMW study of microhydration of 3‐methyl‐3‐oxentanemethanol [6] with one to six water molecules. The authors demonstrated convincingly that water molecules aggregate predominately with themselves, forming initially a one‐dimensional chain and eventually three‐dimensional cube‐like geometries, leaving the hydrophobic parts of the molecule largely non‐solvated [6] .…”

“…One recent highlight is the CP‐FTMW study of microhydration of 3‐methyl‐3‐oxentanemethanol [6] with one to six water molecules. The authors demonstrated convincingly that water molecules aggregate predominately with themselves, forming initially a one‐dimensional chain and eventually three‐dimensional cube‐like geometries, leaving the hydrophobic parts of the molecule largely non‐solvated [6] . A similar pattern was observed in the fenchone‐(H 2 O) N =1–7 complexes [7] .…”