Exploiting isolobal relationships to create new ionic liquids: novel room-temperature ionic liquids based upon (N-alkylimidazole)(amine)BH2+"boronium" ions

Readily prepared imidazole-based boronium ions form stable, hydrophobic, room-temperature ionic liquids (RTIL) with unique electronic and spectroscopic characteristics.     

Dielectrophoretic forces on the nanoscale

We have developed a method of calculation of the dielectrophoretic force on a nanoparticle in a fluid environment where variations in the electric field and electric field gradients are on the same nanoscale as the particle. The Boundary Element Dielectrophoretic Force (BEDF) method involves constructing a solvent-accessible or molecular surface surrounding the particle, calculating the normal component of the electric field at the surface boundary elements, and then solving a system of linear equations for the induced surface polarization charge on each element. Different surface elements of the molecule may experience quite different polarizing electric fields, unlike the situation in the point dipole approximation. A single 100-A-radius ring test configuration is employed to facilitate comparison with the well-known point dipole approximation (PDA). We find remarkable agreement between the forces calculated by the BEDF and PDA methods for a 1 A polarizable sphere. However, for larger particles, the differences between the methods become qualitative as well as quantitative; the character of the force changes from attractive at the origin of the ring for a 50-A sphere, to repulsive for a 75-A sphere. Equally dramatic differences are found in a more complex electrical environment involving two sets of 10 rings.     

A novel route to imidoylbenzotriazoles and their application for the synthesis of enaminones

Reactions of secondary amides 2a-i with 1-chloro-1H-benzotriazole and triphenylphosphine give imidoylbenzotriazoles 3a-i. The treatment of 3a,b,e,g with silyl enol ethers 5a,b in the presence of potassium tert-butoxide provides a new general approach to enaminoketones 6a-h.     

Glycodendriproteins: a synthetic glycoprotein mimic enzyme with branched sugar-display potently inhibits bacterial aggregation

The continuing ability of bacteria to resist current antibiotic treatments highlights the need for alternative strategies for inhibiting their pathogenicity. Bacterial attachment is a major factor in infectivity and virulence. This key binding phase of bacteria to any potential host is mediated by adhesin proteins and so these present an attractive therapeutic target for antiinfective blocking strategies. However, the natural ligands to adhesins are large, typically complex molecules that are difficult to mimic with small molecules. We describe here a method that creates precise synthetic mimics of glycoproteins that are designed to bind adhesins. By using protein-degrading enzymes as the basis for these mimics we have created large-molecule protein ligands that inhibit aggregation of pathogenic bacteria at levels greater than a million-fold higher than small-molecule inhibitors of adhesins.     

Synthesis of group 1 metal 2,6-diphenylphenoxide complexes [M(OC6H3Ph2-2,6)] (M = Li,Na, K,Rb, Cs) and structures of the solvent-free complexes [Rb(OC6H3Ph2-2,6)]x and [Cs(OC6H3Ph2-2,6)x: one-dimensional extended arrays of metal aryloxides

Reaction of 2,6-diphenylphenol (HOC(6)H(3)Ph(2)-2,6) with (n)BuLi, NaH, KH, or Rb or Cs metal in benzene gives the solvent-free complexes [M(OAr)]x in excellent yield. The complex [Rb(OC(6)H(3)Ph(2)-2,6)](x)() exhibits a ladderlike structure in the solid state with triply bridging oxygen atoms and Rb-O distances of 2.743(3), 2.930(2), and 2.973(2) A. The Rb cations interact with the pi-electron cloud of the arene moieties, giving rise to a high Rb coordination number. The cesium-containing congener forms a layered, columnlike structure consisting of [Cs(2)(mu(2)-OAr)(2)] units, with nearly identical Cs-O distances of 2.945(2) and 2.947(2) A. The individual layers are held together solely by Cs-arene pi-interactions.