Synthesis, characterization and calorimetric study of zinc group halide adducts with aniline

The adducts ZnCl2·2an, ZnBr2·1.5an, CdCl2·2an, CdBr2·2an, CdI2·2an, HgCl2·2an and HgBr2·2an (where an = aniline) were synthesized and characterized by elemental analysis, infrared spectroscopy and thermogravimetry and solution calorimetry. Considering the image as well as the D(M − N) values, the following acidity sequence can be established: Zn > Cd > Hg which can be also referring to the hardness of the metal halides. The image values (kJ mol−1) for the reaction MX2 (c) + nL (l) = MX2·nL (c) are: −82.4 ± 3.6 (ZnCl2·2an), −77.1 ± 0.4 (ZnBr2·1.5an), −45.3 ± 1.4 (CdCl2·2an), −45.2 ± 0.7 (CdBr2·2an), −60.3 ± 0.1 (CdI2·2an) and −41.4 ± 6.3 (HgCl2·2an). In the same sequence of compounds, the D(M − N) values (kJ mol−1) are: 143.6, 157.3, 141.2, 126.2, 126.9 and 89.7, respectively.