Structure and Dynamics of Water Dangling OH Bonds in Hydrophobic Hydration Shells. Comparison of Simulation and Experiment

Abstract

Molecular dynamics and electric field strength simulations are performed in order to quantify the structural, dynamic, and vibrational properties of non-H-bonded (dangling) OH groups in the hydration shell of neopentane, as well as in bulk water. The results are found to be in good agreement with the experimentally observed high-frequency (∼3660 cm(-1)) OH band arising from the hydration shell of neopentanol dissolved in HOD/D(2)O, obtained by analyzing variable concentration Raman spectra using multivariate curve resolution (Raman-MCR). The simulation results further indicate that hydration shell dangling OH groups preferentially point toward the central carbon atom of neopentane to a degree that increases with the lifetime of the dangling OH.

Innovative strategy with potential to increase hemodialysis efficiency and safety

“…These Raman spectra were further de-convoluted into five Gaussian sub-bands based using established literature methods - see Supplementary Methods (SM). Although the exact band assignments are slightly different in the literature27282930, the consistent idea is that the bands on the low and high frequency sides are related to strong and weak hydrogen-bonded OH features, respectively. In this work, the three components on the low frequency side are assigned to hydrogen-bonded water, while the remaining two high frequency side components are assigned to non-hydrogen-bonded water.…”

Water around fullerene shape amphiphiles: A molecular dynamics simulation study of hydrophobic hydration

“…142, 224308 (2015) the presence of such defects in aqueous solutions containing nonpolar solute has been detected in experiments. [165][166][167][168] The authors suggested that translational and rotational retardation of water around a hydrophobe is a consequence of dangling bonds formation, which have slower dynamics.…”

Ratiometric detection of Raman hydration shell spectra

“…The vibrational spectra of water in hydration shell are different from the spectra in bulk water; however, they overlap seriously with each other and can hardly be distinguished. Recently, plenty of methods were employed to extract the spectra of hydration shell from the overlapping spectra, such as multivariate curve resolution (MCR) method, [26,[34][35][36][37][38] factor analysis (FA), [39][40][41][42][43][44] and fitting analysis. [45] Such as the FA method, it is assumed that the hydration structures are same in some concentration region.…”

“…For instance, the hydration shell of organic compounds and ions [9,46] were different in different concentration of solutes. MCR method [26,[34][35][36][37][38] assumed that hydration structures kept consistent in sufficiently low concentration region. For example, the hydration shell was thought to be unchanged below 1 M concentration of alkali halide aqueous solutions, [26] and below 1-5 wt % concentration of some organic solutions.…”