Synthesis, structure and properties of cetyltrimethylammonium polyiodides

A series of compounds of the cetyltrimethylammonium cation with polyiodides were synthesized and the crystal structures were determined by single crystal X-ray diffraction. The newly synthesized compounds C16H33N(CH3)3I3 and C16H33N(CH3)3I5 exist as ionic species with a cation consisting of a linear hydrocarbon chain, C16H33N(CH3)3+. How such a large cation influences the crystal packing, shape symmetry and inter molecular associations of the polyiodide ion is of interest. The electrical conductivities were determined from 30 to 65 °C in the solid state. The conductivities of these compounds rises with a rise in temperature and the compounds C16H33N(CH3)3I3 and C16H33N(CH3)3I5 behaves as intrinsic conducting materials. Observations indicate that the addition of iodine increases the ionic conductivity of these compounds.

Cetyltrimethylammonium triiodide, C16H33N(CH3)3I3, and cetyltrimethylammonium pentaiodide, C16H33N(CH3)3I5, were synthesized and their crystal structures determined. Both compounds behave like intrinsically conducting materials.Figure optionsDownload as PowerPoint slideHighlights
► Crystalline polyiodides with a large linear hydrocarbon chain were synthesized.
► Crystal structure and electrical conductivity measurements have been reported.
► The triiodide anion is nearly linear.
► These compounds behave like intrinsically conducting materials.