Raman Spectra of Four Pairs of meso and dl Disubstituted Butanes

Taufen, Harvey J.; Murray, M.; Cleveland, Forrest F.

doi:10.1021/ja01246a033

Cited by 11 publications

(1 citation statement)

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“…The atmosphere over the sample cell was replaced by dried Ar to prevent dew formation on the objective lens and the coverslip surface. The raw spectra were deconvoluted into component Gaussian peaks using Origin 8 software. − …”

Section: Experimental Sectionmentioning

confidence: 99%

Behavior of Polyhydric Alcohols at Ice/Liquid Interface

et al. 2013

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Glycerol (Gly) and 1,3-butanediol (13BD) are widely used as a cryoprotective reagent. Although these compounds have similar chemical structures, their interfacial behavior is not necessarily the same. Frozen aqueous 13BD gives discrete liquid inclusions dispersed in an ice matrix, whereas frozen aqueous Gly forms the film-like liquid phase spread over the entire ice crystal surface. Nuclear magnetic resonance (NMR) measurements of Gly/water at 253 K indicate that the chemical shifts of both water and alcohol OH protons move upfield with increasing concentration of Gly regardless of whether the solution is frozen (<48 wt % Gly) or not (≥48 wt % Gly). In contrast, the chemical shifts remain constant over the entire concentration range for 13BD. Gly forms a molecularly homogeneous mixture with water in any ratio and also interacts with ice similar to liquid water; this leads to the continuous changes in the chemical shifts. However, 13BD and water mainly form individual clusters, which weakly interact with ice. Therefore, the molecular environments are unchanged with the alcohol concentration in this system. The spin−spin relaxation times also indicate that Gly more strongly interacts with ice than 13BD. Raman spectra and the self-diffusion coefficients of water and the alcohols also suggest that 13BD and water molecules form individual clusters in their mixtures and that this tendency is marked at lower temperature and in the presence of ice.

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