In the past few years, spiropyran has emerged as the molecule-of-choice for the construction of novel dynamic materials. This unique molecular switch undergoes structural isomerisation in response to a variety of orthogonal stimuli, e.g. light, temperature, metal ions, redox potential, and mechanical stress. Incorporation of this switch onto macromolecular supports or inorganic scaffolds allows for the creation of robust dynamic materials. This review discusses the synthesis, switching conditions, and use of dynamic materials in which spiropyran has been attached to the surfaces of polymers, biomacromolecules, inorganic nanoparticles, as well as solid surfaces. The resulting materials show fascinating properties whereby the state of the switch intimately affects a multitude of useful properties of the support. The utility of the spiropyran switch will undoubtedly endow these materials with far-reaching applications in the near future.

/pdf/spiropyran-based-dynamic-materials-4c1onvrhup.pdf

Spiropyran-based dynamic materials

A review. Physicochem. properties of ionic liqs. are discussed. Chem. and electrochem. reactivity in ionic liqs. is described including electrode reactions, electrode reaction kinetics, electrosynthesis, etc.

Electrochemical reactivity in room-temperature ionic liquids.

Ionic liquids are liquids composed completely of ions. In the past two decades, ionic liquids have been widely used as “green solvents” replacing traditional organic solvents for organic synthesis and catalysis. In addition, ionic liquids are playing an increasingly important role in separation science. In this Account, the application of ionic liquids in all areas of separation science including extractions, gas chromatography, and supported liquid membrane processes are highlighted.

Ionic liquids in separations.

Sequential separation of light rare-earth elements, thorium and uranium by miniaturized extraction chromatography: Application to isotopic analyses of silicate rocks

https://pure.mpg.de/pubman/item/item_1925102_4/component/file_1925101/562340.pdf

Poly(ionic liquid)s: Polymers expanding classical property profiles

Separation and preconcentration of strontium from biological, environmental, and nuclear waste samples by extraction chromatography using a crown ether.

A new process for the extraction and recovery of strontium from acidic waste streams is described. In this process, called SREX (for Strontium Extraction), strontium is extracted from acidic ( ≥ 1 M HNO3) solution using a 0.20M solution of di-t-butylcyclohexano-18-crown-6 in 1-octanol. Extracted strontium is readily stripped from the organic phase using either water or dilute (<0.05 M) HNO3. Tests of the process on a synthetic dissolved sludge waste solution show that only strontium, barium, and technetium are appreciably extracted by the crown ether. Prolonged exposure of the process solvent to nitric acid at elevated temperatures or to ≤ 50 Wh/L γ radiation from a 60Co source produces essentially no deterioration in its performance. Benchtop batch countercurrent extraction experiments show that 99.7% of the strontium initially present in a feed solution can be removed in only three extraction stages.

Srex: a newprocess for the extraction and recovery of strontium from acidic nuclear waste streams

Influence of solvent structural variations on the mechanism of facilitated ion transfer into room-temperature ionic liquids

Addition of water to 1-decyl-3-methylimidazolium bromide is shown to result in its spontaneous self-organization and the concomitant formation of a liquid-crystalline gel, thus providing a simple means of preparing a supramolecular assembly comprising a room-temperature ionic liquid.

Lyotropic liquid-crystalline gel formation in a room-temperature ionic liquid.

The Sr(II)-crown ether complexes formed in a room-temperature ionic liquid (RTIL), 1-methyl-3-pentylimidazolium bis[(trifluoromethyl)sulfonyl]amide, have been studied by X-ray absorption fine structure measurements at the Sr K-edge. When a Sr(NO(3))(2)-crown ether complex is directly dissolved in a water-saturated RTIL, both nitrate ligands and the crown ether coordinate the Sr, as observed in a conventional two-phase water-octanol system. When the cationic Sr-crown ether complex is created in a two-phase water-RTIL system, however, only cationic Sr-crown ether complexes are observed in the RTIL phase. This difference in the coordination complexes arises from differences in the mechanism of cation extraction between the RTIL and conventional molecular organic solvents, a finding with important implications for synthesis, catalysis, and ion separations using two-phase water-RTIL systems.

Mark L. Dietz

Papers

Separation and preconcentration of strontium from biological, environmental, and nuclear waste samples by extraction chromatography using a crown ether.

Srex: a newprocess for the extraction and recovery of strontium from acidic nuclear waste streams

Influence of solvent structural variations on the mechanism of facilitated ion transfer into room-temperature ionic liquids

Lyotropic liquid-crystalline gel formation in a room-temperature ionic liquid.

EXAFS investigations of the mechanism of facilitated ion transfer into a room-temperature ionic liquid.