Solvent-free mechanochemical synthesis of organic proton conducting salts incorporating imidazole and dicarboxylic acids

Solventless mechanochemical synthesis by manual grinding was applied to grow organic proton conducting salts, imidazole-succinic acid (C3H4N2-HOOC(CH2)2COOH) and imidazole-glutaric acid (C3H4N2-HOOC(CH2)3COOH). This synthesis method induces crystallization and provides the phase-pure compounds. The compounds exhibit different electric conducting behavior and activation energies Ea compared with the reported single crystals obtained from the solution method. The difference in conducting property can be related to intrinsic defects and structural disorder introduced by mechanochemical grinding, indicating that the mechanochemical method bears strong capability for tuning conductivities. Moreover, complete deuteration of the organic salts is achieved by the method. The mechanochemical synthesis of organic salts also holds high potential for the actual industrialized large-scale production.

Automated summary

Solventless mechanochemical synthesis by manual grinding was used to successfully synthesize organic proton conducting salts imidazole-succinic acid and imidazole-glutaric acid. This method allows for crystallization and produces phase-pure compounds. The compounds exhibit different electrical conducting behavior and activation energies compared to single crystals obtained from a solution method. The differences in conducting properties are attributed to defects and structural disorder introduced by mechanochemical grinding, indicating the strong capability of this method for tuning conductivities. Additionally, complete deuteration of the organic salts is achieved, highlighting the potential for large-scale industrial production of organic salts through mechanochemical synthesis.