Synthesis and Structure of 4-Acetyl-N,N,N-Trimethylanilinium Iodide

4-Acetyl-N,N,N-trimethylanilinium iodide (1) is obtained by the N-alkylation reaction of 4-((trimethylsilyl) ethynyl)aniline. The structure of compound 1 is solved using the single crystal X-ray diffraction analysis for the first time. 4-Acetyl-N,N,N-trimethylanilinium iodide has the layered packing. The layers, in which cations and anions alternate, are parallel to each other. In the IR spectrum of compound 1, absorption bands at 1676 cm^–1, 2949 cm^–1, and 3021 cm^–1 correspond to C=O and C–H stretching vibrations (aliphatic and aromatic). Compound 1 decomposes in two distinct steps. At the first step (172-200 °C), 4-acetyl-N,N,N-trimethylanilinium iodide decomposes with a removal of methyl iodide (i.e., inverse methylation reaction). At the second step (200-285 °C), 1-(4-(dimethylamino)phenyl)ethanon formed evaporates. Judging by the absence of the carbon residue, evaporation proceeds without decomposition.