The crystalline forms of nine hydrochloride salts of substituted tryptamines

The crystal structures of the hydrochloride salts of nine substituted tryptamines, namely, 1-methyltryptammonium chloride, C₁₁H₁₅N₂⁺·Cl^-, (1), 2-methyl-1-phenyltryptammonium chloride, C₁₇H₁₉N₂⁺·Cl^-, (2), 5-methoxytryptammonium chloride, C₁₁H₁₅N₂O⁺·Cl^-, (3), 5-bromotryptammonium chloride, C₁₀H₁₂BrN₂⁺·Cl^-, (4), 5-chlorotryptammonium chloride, C₁₀H₁₂ClN₂⁺·Cl^-, (5), 5-fluorotryptammonium chloride, C₁₀H₁₂FN₂⁺·Cl^-, (6), 5-methyltryptammonium chloride, C₁₁H₁₅N₂⁺·Cl^-, (7), 6-fluorotryptammonium chloride, C₁₀H₁₂FN₂⁺·Cl^-, (8), and 7-methyltryptammonium chloride, C₁₁H₁₅N₂⁺·Cl^-, (9), are reported. The seven tryptamines with N-H indoles, (3)-(9), show very similar structures, with N-H...Cl hydrogen-bonding networks forming two-dimensional sheets in the crystals. These sheets are combinations of R₄²(8) and R₄²(18) rings, and C₂¹(4) and C₂¹(9) chains. Substitution at the indole N atom reduces the dimensionality of the hydrogen-bonding network, with compounds (1) and (2) demonstrating one-dimensional chains that are a combination of different rings and parallel chains.