RESUMO
The nature of the interactions between 1,3-dialkylimidazolium cations and noncoordinating anions such as tetrafluoroborate, hexafluorophosphate, and tetraphenylborate has been studied in the solid state by X-ray diffraction analysis and in solution by (1)H NMR spectroscopy, conductivity, and microcalorimetry. In the solid state, these compounds show an extended network of hydrogen-bonded cations and anions in which one cation is surrounded by at least three anions and one anion is surrounded by at least three imidazolium cations. In the pure form, imidazolium salts are better described as polymeric supramolecules of the type {[(DAI)(3)(X)](2+)[(DAI)(X)(3)](2-)}(n) (where DAI is the dialkylimidazolium cation and X is the anion) formed through hydrogen bonds of the imidazolium cation with the anion. In solution, this supramolecular structural organization is maintained to a great extent, at least in solvents of low dielectric constant, indicating that mixtures of imidazolium ionic liquids with other molecules can be considered as nanostructured materials. This model is very useful for the rationalization of the majority of the unusual behavior of the ionic liquids.
RESUMO
The structure of the title compound, [PtCl(2)(C(5)H(5)N)(C(2)H(6)S)], consists of discrete molecules in which the Pt-atom coordination is slightly distorted square planar. The Cl atoms are trans to each other, with a Cl-Pt-Cl angle of 176.60 (7) degrees. The pyridine ligand is rotated 64.5 (2) degrees from the Pt square plane and one of the Pt-Cl bonds essentially bisects the C-S-C angle of the dimethyl sulfide ligand. In the crystal structure, there are extensive weak C-H...Cl interactions, the shortest of which connects molecules into centrosymmetric dimers. A comparison of the structural trans influence on Pt-S and Pt-N distances for PtS(CH(3))(2) and Pt(pyridine) fragments, respectively, in square-planar Pt(II) complexes is presented.