Far-Infrared Investigation of the Benzene–Water Complex: The Identification of Large-Amplitude Motion and Tunneling Pathways

Abstract

The far-infrared spectrum of the weakly OH···π hydrogen-bonded benzene–water complex has been studied in neon and argon matrices, below 30 K. The in-plane water libration has been observed in both neon and argon for H2O and D2O complexed with C6H6 and C6D6 but not for the corresponding complexes involving HDO. Both H2O and D2O can tunnel between the two possible hydrogen bonds. This is not possible for HDO. The reported far-infrared observations have implications for the interpretation of the previously obtained molecular beam microwave spectrum of the benzene–water complex.

Noncovalently bound molecular complexes beyond diatom–diatom systems: full-dimensional, fully coupled quantum calculations of rovibrational states

“…Numerous spectroscopic studies have been directed at benzene-H 2 O and benzene-HDO complexes. [98][99][100][101][102][103][104] A major impetus for them was the realization that benzene-H 2 O and benzene-HDO are highly nonrigid, which emerged first from the matrix isolation study. 105 Their fluxional character was characterized more precisely by the subsequent microwave 98,99 and IR spectra.…”

Beyond the Molecule: Intermolecular Forces from Gas Liquefaction to X−H⋅⋅⋅π Hydrogen Bonds

“…The answer is: yes, it does, even if it has not yet supported by structural studies based on X-ray or neutron diffraction. Actually, numerous investigations combining IR spectroscopic data and quantum mechanical studies have demonstrated that the 1 : 1 π-H-bond complex of benzene with water is stable in the gas phase and in solution, [85] In the more stable geometrical arrangement the water molecule sits above the aromatic ring, with one hydrogen atom oriented toward the ring, as sketched in Figure 37.…”

Wetting of a Hydrophobic Surface: Far-IR Action Spectroscopy and Dynamics of Microhydrated Naphthalene

“…It is a major player in determining the properties of bulk materials and a key factor in supramolecular chemistry and biochemistry. , Hydrophobicity is, for instance, crucial in processes involving molecular recognition, macromolecular folding, or reversible binding of water to biomolecular or catalytic active sites. − The weak interactions between water and polycyclic aromatic hydrocarbons (PAHs), addressed in this investigation, typically result in their insolubility. Nevertheless, soot or carbonaceous particles play a relevant role in the nucleation of water in the atmosphere − and in interstellar environments. , First-principle approaches have often adopted microhydration strategies to understand water–solvent versus water–water interactions, in which the solvation shell of a given substrate is scrutinized in isolated clusters with a well-defined number of water molecules. ,,− IR spectroscopy has been demonstrated to be an excellent tool for investigating interactions in water–PAH clusters and related systems, ,,,, along with complementary work in the microwave ,− and (V)­UV , spectral regions. Apart from structural elucidation, those studies have exposed the subtle balance between the strong hydrogen bonding within the water network and the weaker dipole−π interactions between water and the PAH substrate.…”

“…9 , 10 First-principle approaches have often adopted microhydration strategies to understand water–solvent versus water–water interactions, in which the solvation shell of a given substrate is scrutinized in isolated clusters with a well-defined number of water molecules. 1 , 2 , 11 − 17 IR spectroscopy has been demonstrated to be an excellent tool for investigating interactions in water–PAH clusters and related systems, 12 , 13 , 15 , 16 , 18 along with complementary work in the microwave 17 , 19 − 21 and (V)UV 22 , 23 spectral regions. Apart from structural elucidation, those studies have exposed the subtle balance between the strong hydrogen bonding within the water network and the weaker dipole−π interactions between water and the PAH substrate.…”