Capturing CO 2 from flue gas streams under near ambient conditionse.g. coal-fired power plantshas traditionally involved the use of aqueous alkanol amine solutions. Aqueous solvent-based processes are energy intensive, as solvent regeneration can be costly. With growing concern over climate change, alternative CO 2 capture technologies that are energy and cost efficient are required. We have established that nonaqueous silylamines can be used to efficiently and reversibly capture and release CO 2 via the formation of reversible ionic liquids. We now report their unique, enhanced CO 2 uptake at room temperature under 1 atm of CO 2 , as silylamines exhibit CO 2 capture capacities greater than that expected from the conventional stoichiometry of a 2:1 amine to CO 2 mole ratio. Experimental evidence is presented supporting the formation of a carbamic acid species in equilibrium with an ionic liquid network of ammonium−carbamate ion pairs to give a 3:2 amine to CO 2 mole ratio. This is the f irst report of the stabilization of carbamic acid by reversible ionic liquids. Stabilization of carbamic acid leads to a significant increase in CO 2 capacity (30% on average) over conventional amine solutions for CO 2 capture.

We describe investigations of insulin release from thermoresponsive microgels using variable temperature (1)H NMR. Microgel particles composed of poly(N-isopropylacrylamide) were loaded with the peptide via a swelling technique, and this method was compared to simple equilibrium partitioning. Variable temperature (1)H NMR studies suggest that the swelling loading method results in enhanced entrapment of the peptide versus equilibrium partitioning. A centrifugation-loading assay supports this finding. Pseudo-temperature jump (1)H NMR measurements suggest that the insulin release rate is partially decoupled from microgel collapse. These types of direct release investigations could prove to be useful methods in the future design of controlled macromolecule drug delivery devices.

An abiotic formation of meso- and dl-tartrates in 80% yield via the cyanide-catalyzed dimerization of glyoxylate under alkaline conditions is demonstrated. A detailed mechanism for this conversion is proposed, supported by NMR evidence and 13C-labeled reactions. Simple dehydration of tartrates to oxaloacetate and an ensuing decarboxylation to form pyruvate are known processes that provide a ready feedstock for entry into the citric acid cycle. While glyoxylate and high hydroxide concentration are atypical in the prebiotic literature, there is evidence for natural, abiotic availability of each. It is proposed that this availability, coupled with the remarkable efficiency of tartrate production from glyoxylate, merits consideration of an alternative prebiotic pathway for providing constituents of the citric acid cycle.

A dinuclear silver hydride and an umpolung reaction of CO 2A silver lining: An N-heterocyclic carbene ligand supports a robust hydride-bridged disilver cation, with a silver-silver distance shorter than that in silver metal. Proton and silver NMR studies refl ect strong H-Ag and Ag-Ag dipolar coupling. The cation reacts very slowly with free CO 2 , but transfers hydride rapidly to CO 2 activated by a suitable Lewis base.

The cuticular hydrocarbon components of four castes ofReticulitermes virginicus (Banks) have been identified and quantitated. Components identified includen-alkanes; 2-, 3-, 11-, 13-, and 15-methyl-alkanes; 11,15-dimethylalkanes, (Z)-9-alkenes; (Z,Z)-7,9-dienes; and (E/Z)-6,9-dienes ranging in carbon number from C21 to C40. All caste forms ofR.virginicus contained the same components, but showed caste-specific proportions. Comparison of these hydrocarbons with those of the sympatric termiteR. flavipes (Kollar) suggest that cuticular hydrocarbons might serve as species- and caste-recognition cues. A bioassay was developed to test this species-recognition hypothesis, with the experimental results supporting the hypothesis.