deviation from planarity—such as observed during cis/trans isomerization occurring in protein folding—should result in major changes in reactivity and other chemical properties of the amide bond. For example, rotation of the amide bond is coupled with formal rehybridization of the nitrogen atom to sp, with attendant pyramidalization and greatly increased basicity. The most common experimental a...

The protonation constants of the ligand 3,6,9,16,19,22-hexaazatricyclo[22.2.2.2]triaconta-1(26),11(12),13,24,27, 29-hexaene (L, BPXD) have been determined in water at 25°C by potentiometric procedures and indicate a lower basicity than that corresponding to the analogue ligand with m-xylyl spacers between the diethylenetriamine subunits (BMXD). The crystal structure of a salt of H6L 6+ containi...

The thermal decomposition of hydrotalcites (HTs) with different interlayer anions in the 298-523 K region has been investigated by using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and IR, 27Al MAS-NMR and X-ray absorption near-edge structure (XANES) spectroscopy. The thermal stability of the HT with interlayer oxalate was remarkably higher...

A comprehensive study of the solution and solvation of linear alcohols (propan-1-ol, butan-1-ol and pentan-1-ol) in ionic liquids (ILs) is presented. The effect of the alkyl chain size of both alcohols and ILs (1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [CnC1im][NTf2], ionic liquid series) on the thermodynamic properties of solution and solvation was used to obtain insight i...

The stability constants of the 1:1 complexes formed between methylphosphonylphosphate (MePP(3-)), CH(3)P(O)(-) (2)-O-PO3(2-), and Mg(2+), Ca(2+), Sr(2+), Ba(2+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), or Cd(2+) (M(2+)) were determined by potentiometric pH titration in aqueous solution (25 degrees C; l = 0.1 M, NaNO(3)). Monoprotonated M(H;MePP) complexes play only a minor role. Based on previo...

The photochemistry of several 2-(2-nitrophenyl)ethyl-caged compounds including caged thymidine nucleosides was studied by nanosecond laser flash photolysis and stationary illumination experiments with quantitative HPLC analysis for quantum yields and product distribution. Effects of solvent basicity and acidity were investigated by varying the H2O content and HCl concentration, respectively, in...

For the purpose of the brain delivery of peptides, the structural specificity of adsorptive-mediated endocytosis at the blood-brain barrier was studied by measuring transport of a newly synthesized basic peptide 001-C8, H-MeTyr-Arg-MeArg-D-Leu-NH(CH2)aNH2, using primary cultured bovine brain capillary endothelial cells. The apparent uptake of [125I]001-C8 increased time-dependently and reached ...

This contribution explores the effect of several solvent properties, such as volatility, polarity, and Lewis basicity on the formation of molecular self-assembled nanostructures in the solid state, obtained either by casting of related solutions or by complete solvent evaporation, using seven solvents representative of common classes of coordinating organic solvents, of an amphiphilic Zn(II) Sc...