3-Chloro- N , N -di-methyl-propan-1-aminium chloride.

The organic cation in the title mol-ecular salt, C ₅ H ₁₃ NCl ⁺ ·Cl ^- , exhibits the gauche effect with a C-H bond of the C atom β to the chloro group donating electrons to the anti-bonding orbital of the C-Cl bond to stabilize the gauche conformation [Cl-C-C-C = -68.6 (6)°], as confirmed by DFT geometry optimizations that show a lengthening of the C-Cl bond relative to that of the anti conformation. Of further inter-est is the higher point group symmetry of the crystal (), compared that of the that of the mol-ecular cation, which arises from a supra-molecular head-to-tail square arrangement of four mol-ecular cations that circulate in a counterclockwise direction when viewed down the tetra-gonal c axis.
(© Bond and Silwal 2023.)