Rotational Structure of Water in a Hydrophobic Environment:  Carbon Tetrachloride

Abstract

Infrared spectroscopy has been used to probe the interaction between water and the hydrophobic solvent, carbon tetrachloride. At room temperature, water exists as monomers in carbon tetrachloride, presenting a system for studying the rotational properties of water free of strong hydrogen-bonding. The rotational structure suggests a very anisotropic motion consisting of essentially free rotation about the symmetry axis and highly hindered rotation about the two perpendicular axes of the asymmetric water molecule. The rotational lifetime is significantly shortened relative to gas-phase water. An upper limit of 0.93 ps is deduced from the spectrum. Interaction with carbon tetrachloride also slightly enhances the intensity of the symmetric stretch. The results are compared with results of interactions between water and the cations Li+, Na+, K+, and Cs+. It is concluded that the attractive interaction is between the oxygen of water and the electropositive carbon of carbon tetrachloride.

Neutron scattering observation of quasi-free rotations of water confined in carbon nanotubes

“…This happens because the symmetry axis of the ice channel (Fig. 1) is very close to the rotation axis associated to the B constant of water molecules arranged in the single-file configuration, while rotations associated to A and C constants can be ignored, being very short-lived41.…”

Hydrogen Bonding between Water and Tetrahydrofuran Relevant to Clathrate Formation

“…38 The spectrum at -5 °C Like room temperature, the symmetric stretch is relatively enhanced due to interaction between oxygen of water the positively charged carbon atom of carbon tetrachloride. Steric hindrance due to this interaction limits water rotational motion to that about the symmetry axis; the symmetry axis moment of inertia is nearly identical to that in the gas phase.…”

“…38 The OH stretch region consists of a symmetric stretch at This work thus investigates the specific water-THF interaction. The target temperature is -5 °C since at high pressure, clathrates form at this temperature and are stable to above 0° C. The -5° C temperature provides comparable thermal energies to clathrate formation conditions.…”

Insights into hydrogen bonding via ice interfaces and isolated water

“…This attraction prevents free rotation of the water molecule, greatly simplifying the water spectrum. 52 Water spins nearly freely on its molecular axis with a moment of inertia equal to that of water in the gas phase, but rotation in the other two directions is nearly quenched. H-donor interactions perturb the free rotation, hence are readily detected.…”

“…The carbon atom in CCl 4 is positively charged due to the electron withdrawing chlorine atoms. The water lone pairs are attracted to this positively charged carbon, restricting rotational motion to symmetry-axis rotation, 52 greatly simplifying the water spectrum. The hydrogen atoms in water are fully accessible for interaction.…”