Room temperature ionic liquids (RTILs) are substances composed entirely of ions and are liquids at or below 100 degrees C. Ionic conductivity of RTIL is one of the most important physical properties of these unique substances that determine their potential applications as a new medium for capacitors, fuel and solar cells as well as in separation systems. The quality of performance of these devices relies on the understanding of ionic transport of RTIL on a nanoscale. In this letter, we use ionic current carried by RTILs in single nanopores as a probe for their nanoscale transport properties. We show that the conductivity of RTILs through nanopores is significantly less than corresponding bulk values. Our experiments allowed us to address the nature of the interaction of these confined RTILs with charged surfaces. Electrostatic interactions of RTILs with nanopores are the basis for the formation of ionic diodes rectifying transport of the constituent ions.

New achiral sulfamide, phosphoric triamide, and thiophosphoric triamide compounds have been synthesized. Their activity as hydrogen bond catalysts for the Friedel-Crafts and Baylis-Hillman reactions compares favorably with that of a known and active thiourea catalyst. The new compounds were also studied by X-ray crystallography and their solid state structures are described.Hydrogen-bonding is a ubiquitous force in nature. Not until relatively recently have chemists begun to implement this force in catalysis, but already with extraordinary success. 1 The majority of hydrogen bonding (HB) catalysts incorporates the thiourea functional group. 2 Advantages of the thiourea include air and water stability, ease of synthesis and modification, and activity toward a wide range of substrates.Despite their success, thiourea catalysts suffer from some significant disadvantages. First, they have relatively weak activity, frequently necessitating high catalyst loading and/or long reaction times to achieve a satisfactory yield. A more active HB catalyst would be desirable. A second concern for the thiourea functionality is its sensitivity to heat. At elevated temperatures (>75 °C), some thiourea catalysts have been reported to decompose. 3 Although the majority of HB catalyzed reactions are run at or below room temperature, a more thermally robust catalyst could allow for a more versatile catalyst system. Several non-thiourea HB catalysts have been developed as potential alternatives. These can be categorized into neutral and protonated catalysts. Notable examples of neutral compounds include those based on squaramide, 4 sulfonamide, 5 and urea-N-sulfoxide 6 structures. Protonated catalysts include those based on guanidinium, 7 quinolinium thioamide, 8 and ammonium 9 structures. While the latter catalysts tend to activate electrophiles more strongly than the former, due to their increased acidity, they are incompatible with basic functionality. This serves to limit substrate scope and places restrictions on catalyst design. Based on this consideration, we focused on improved neutral thiourea alternatives. Our aim was to develop new neutral molecular designs that display improved catalytic activity over the thiourea motif. We focus in this communication on the relative catalytic efficiency of these structural motifs.We identified three motifs as promising candidates: i) sulfamides, ii) phosphoric triamides, and iii) thiophosphoric triamides. All of the structures, like thioureas, join two or more amidelike groups to a single electron-withdrawing atom ( Figure 1). As such, they were expected to exhibit a similar mode of activity toward common substrates. Replacement of the thiocarbonyl group with sulfone, phosphorus oxide, or phosphorus sulfide tethers however was anticipated to give these compounds modified, perhaps improved, binding properties. In addition, the *Corresponding author. Tel.: 949-824-5844; fax: 949-824-2210; kjshea@uci.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has...

Antisense oligonucleotides (ASOs) conjugated to triantennary N-acetyl galactosamine (GalNAc) ligands represent an emerging approach to antisense therapy. Our current generation of GalNAc-ASO conjugates link the GalNAc to the 5′-terminus of the ASO. The conjugation reaction can be accomplished using solution-phase or solid-phase techniques. Here we show a direct comparison of a solution-phase and a solid-phase conjugation strategy. The solution-phase approach, using amine-pentafluorophenyl (PFP) ester coupling, is higher yielding and gives material of slightly higher purity, but requires several additional unit operations and longer production time. The solid-phase approach, using a protected GalNAc ligand phosphoramidite, is more expedient, but results in lower yield and purity. Both strategies efficiently deliver conjugated material in excellent purity.

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Linear R-olefins (LAOs) of controlled molecular weight and low PDI were synthesized in high yield by the polyhomologation reaction of dimethylsulfoxonium methylide (1) with triallylborane (2). Following polymerization, propionic acid or trimethylamine N-oxide dihydrate (TAO) was used to afford R-vinyl-ω-methyl or R-vinyl-ω-hydroxy end-functionalized polymethylene, respectively. Controllable molecular weights up to 13 kDa were obtained by varying the initial monomer/catalyst ratio, and the resultant polymers had very narrow polydispersities (PDI < 1.08). Although polymer yields were generally high, quantities of oxidized side products were observed in R-vinyl-ω-methyl samples; however, these oxidized side products could be removed for samples of low molecular weights (C n e 36).

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