Three new quinuclidine-based structures: second harmonic generation response for 1,2-bis(1-azoniabicyclo[2.2.2]octan-3-ylidene)hydrazine dichloride

Abstract

The crystal structures of three quinuclidine‐based compounds, namely (1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine monohydrate, C7H13N3·H2O (1), 1,2‐bis(1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine, C14H22N4 (2), and 1,2‐bis(1‐azoniabicyclo[2.2.2]octan‐3‐ylidene)hydrazine dichloride, C14H24N42+·2Cl− (3), are reported. In the crystal structure of 1, the quinuclidine‐substituted hydrazine and water molecules are linked through N—H…O and O—H…N hydrogen bonds, forming a two‐dimensional array. The compound crystallizes in the centrosymmetric space group P21/c. Compound 2 was refined in the space group Pccn and exhibits no hydrogen bonding. However, its hydrochloride form 3 crystallizes in the noncentrosymmetric space group Pc. It shows a three‐dimensional network structure via intermolecular hydrogen bonding (N—H…C and N/C—H…Cl). Compound 3, with its acentric structure, shows strong second harmonic activity.