Bonding, hydrogen alcohols

However, the fluorescence characteristics of these compounds are strongly solvent-dependent. In protic solvents such as alcohols, hydrogen bonds can be formed between the nitrogen atoms and the solvent molecules. This results in an inversion of the lowest-lying rt-n and n-n states. As the lowest-lying transition becomes of n —> n character in these solvents, the fluorescence quantum yield is much higher than in hydrocarbon solvents. 

Alcohols follow trends similar to Hydrocarbons, but alcohols hydrogen bond, giving them considerably higher boiling points and water solubilities than similar-weight tiydrocarbons. 

To investigate the effect of alcohol hydrogen-bond donor (HBD) strength in a systematic way, a series of modifiers possessing a common 4-teri-octylphenoxy ethanol core element were prepared, in which the properties of the substituent attached to the alcohol carbon atom were varied. These modifiers were evaluated with respect to both the cesium extraction strength they afforded when used in combination with BC6 and the HBD strength of the solvent as assessed using the solvatochromic parameter E. ... 

The excess enthalpy can be related to the number of alcohol—alcohol hydrogen bonds formed in the alcohol-hydrocarbon solution compared to those formed in pure alcohol. Considering the enthalpy of formation of a hydrogen bond hA to be independent of the degree of aggregation, the excess enthalpy is given by... 

C4mim][PF6] hydrogen bonding abilities are similar to that of short chain alcohols, hydrogen bond donor abilities similar to water and acetonitrile but dipolarity/ polarizability are substantially higher than for lower chain alcohols but similar to those of water and DMSO [123],... 

The results observed for the alkene-alkanol systems in the study of Letcher et al. [55], i.e. very high selectivities and capacities, are explained in terms of a high preferential affinity of the ionic liquid for the alcohol (hydrogen-bonding, polar interactions) over the aliphatic component. However, as explained above, ionic liquids based on halogen anions are undesirable. The studies of the research group of Arce et al. [56-58] in the selective... 

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