Molecular aggregation phenomena in solution: an energy dispersive X-ray diffraction study of concentrated imidazole water solutions

An energy dispersive X-ray diffraction study of concentrated imidazole wate r solutions is reported. It reveals the presence of extended solute-solute aggregates. Such results can be interpreted in terms of a branch of a pseud o-helix of imidazole dimers interacting with water molecules. The mean dist ance between molecules in the dimer is similar to 3.7 Angstrom, while the m ean distance between dimers is 4.75-4.95 Angstrom depending on concentratio n. The model structure functions and theoretical radial distribution functi ons fit the experimental data. (C) 1999 Elsevier Science B.V. AU rights res erved.