Comparative studies of the molecular structure of 1-R-1,2,3,4,5,6-hexamethylbenzenonium ions: Molecular and crystal structure of 1-chloromethyl-1,2,3,4,5,6-hexamethylbenzonium tetrachloroaluminate

1-Chloromethyl-1,2,3,4,5,6-hexamethylbenzenonium tetrachloroaluminate is investigated in an X-ray diffraction study. The crystals are monoclinic: a = 8.910(2), b = 12.290(3), c = 17654(4) Angstrom, beta = 111.57(2)degrees, space group P2(1)/c. The AlCl4- anion has an almost perfect tetrahedral configuration; the average length of the Al-Cl bond is 2.130(3) Angstrom. For cations, the symmetry is close to C-s. The C(2)-C(6) atoms lie in a plane (within +/-0.012(5) Angstrom), and the C(1) atom deviates from the plane by 0.113(5) Angstrom to the side that is opposite to the CH2Cl group. Effects of the environment, as well as the effect of the nature of the R group, on the structure 1-R-1,2,3,4,5,6-hexamethylbenzenonium are considered.