Different cation-protonation patterns in molecular salts of unsymmetrical dimethyhydrazine: C2H9N2·Br and C2H9N2·H2PO3

We describe the syntheses and crystal structures of two molecular salts containing the 1,1-dimethylhydrazinium cation, namely 1,1-dimethylhydrazin-1-ium bromide, C2H9N2+·Br−, (I), and 2,2-dimethylhydrazin-1-ium dihydrogen phosphite, C2H9N2+·H2PO3−, (II). In (I), the cation is protonated at the methylated N atom and N—H...Br hydrogen bonds generate [010] chains in the crystal. In (II), the cation is protonated at the terminal N atom and cation-to-anion N—H...O and anion-to-anion O—H...O hydrogen bonds generate (001) sheets.