Investigation of the thermal and conductive properties of oxalic acid salts with planar and undulating proton-conducting layers

Abstract

The physical properties of two proton conductors 1H-1,2,4-triazol-4-ium hydrogen oxalate (TriOX) and 1H-imidazol-3-ium hydrogen oxalate (ImiOX) were investigated.

Effect of Azole Counterions on Thermal and Transport Properties of the Hydrated Salts of Hemimelitic Acid

“…A comparative analysis of the crystal structures of hydrated salts of hemimelitic acid with imidazole (ImiHem•H 2 O) and pyrazole (PyrHem•H 2 O) was carried out. 15 imidazole (ImiOxa), 14 and triazole (TriOxa) 16 is quite different. PyrOxa and TriOxa crystallize in a triclinic structure, whereas ImiOxa crystallizes in a monoclinic structure.…”

“…To sum up, the crystal data and structure refinement are very similar in both analyzed salts: ImiHem·H 2 O and PyrHem·H 2 O , which is uncommon in heterocyclic salts with carboxylic acids. The organization of molecules in crystals obtained based on oxalic acid with pyrazole ( PyrOxa ), imidazole ( ImiOxa ), and triazole ( TriOxa ) is quite different. PyrOxa and TriOxa crystallize in a triclinic structure, whereas ImiOxa crystallizes in a monoclinic structure.…”

“…16,14 The formation of 3D-type proton transport pathways was observed in imidazolium oxalate and triazolium oxalate. 16 Hydrogen bonds involving N + −H•••O − have been observed in the crystal structures of imidazolium phthalate and imidazolium terephthalate. Analysis of the crystal structure of these salts shows that N + −H•••O − interaction creates a helix motif.…”

“…The ions in pyrazole oxalate form a planar structure with 1D-type proton transport pathways. 16,14 The formation of 3D-type proton transport pathways was observed in imidazolium oxalate and triazolium oxalate. 16 Hydrogen bonds involving N + −H•••O − have been observed in the crystal structures of imidazolium phthalate and imidazolium terephthalate.…”

Enhanced proton conductivity in amino acid based self-assembled non-porous hydrogen-bonded organic frameworks

“…14,15,21 In this regard, the use of amino acid -oxalic acid co-crystalline systems appears to be suitable in designing efficient proton conductors that are cheap and eco-friendly. 22 Herein, we report three organic salt-cocrystal systems, b-alaninium oxalate hemihydrate (BALAOA), glycinium oxalate (GLYOA), and L-leucinium oxalate (LEUOA) as possible ultra-high proton conductors for fuel cell applications.…”