Raman scattering and water structure in nonionic amphiphile solutions.
The structure of water in aqueous solutions of polyoxyethylene nonionic amphiphiles ${\mathrm{C}}_{10}$${\mathrm{E}}_{5}$, where ${\mathrm{E}}_{5}$ denotes ${\mathrm{H}}_{21}$(${\mathrm{OCH}}_{2}$${\mathrm{CH}}_{2}$${)}_{5}$OH, is studied by Raman scattering along an isothermal path crossing the isotropic one-phase region from 0 to 1 amphiphile volume fraction \ensuremath{\varphi}. The isotropic OH stretching-vibration spectrum points out a water behavior that depends on the amphiphile concentration. The data analysis is performed using the bond-percolation model developed for water. The interpretation of scattering data leads to the following structural picture for the water in the systems: for \ensuremath{\varphi} lower than 0.75, water is partially bound to the oxyethylene groups of the amphiphile; above \ensuremath{\varphi}=0.75 all water present in the system is bound. Analogously to the behavior of water in confined geometries, the structure of bound water presents a local fourfold-coordinated environment.
Water partitioning in "dry" poly(ethylene oxide) alcohol (CmEn) nonionic surfactant--a proton NMR study.
A proton NMR titration study is presented where in small increments quantities of water were added to "dry" CmEn nonionic surfactant. For a particular range of compositions, two resonances for the water/hydroxyl protons were observed that display large chemical shift increases as water content is increased indicating that water must partition between two chemical environments with a surprisingly slow chemical exchange rate. A detailed mechanism of how the increasing amounts of water are incorporated into the surfactant medium is presented accounting for all observed spectral changes.
Luminescence Phenomena Involving Metal Enolates
1 
Introduction 
 
2 
Metal Enolates 
 
3 
Luminescence of Rare-Earth Enolates 
 
4 
Luminescence Involving s, p and d Metal Block Enolates 
 
5 
Applications 
 
6 
Acknowledgments 
 
 
 
Keywords: 
 
luminescence phenomena involving metal enolates; 
chemistry of metal β-diketonate complexes; 
luminescence of rare-earth enolates; 
photoluminescence of rare-earth β-diketonates; 
diketonate ligand–rare-earth ion energy transfer rates; 
luminescence involving s, p and d metal block enolates; 
photoluminescence of d-transition metal enolates; 
applications - time-resolved detection of luminescence for bioassays