Thermochemistry of some amino acid-based layered copper chlorides

Three different tetrachlorocuprates A2CuCl4 containing 3-aminopropionic, 4-aminobutyric and 6-aminohexanoic acid cations in A-sublattice were synthesized. The temperatures of the decomposition onset for A2CuCl4 were found to increase slightly with the aliphatic chain length in A cation. The standard reaction enthalpies for the formation from organic ammonium chloride and anhydrous copper (II) chloride at T = 298.15 K, Delta rH degrees hal,298 (hal denotes the formation from the source halides), were determined by isoperibolic solution calorimetry. The layer shift parameter S was introduced for the sake of comparison of thermochemical and structural data. Both original and literature thermochemical data indicate that simultaneous increase in S and decrease in the molar volume, Vmol, leads to a decrease in the Delta rH degrees hal,298.

Automated summary

Three different tetrachlorocuprates containing organic ammonium cations were synthesized, and their thermal properties were investigated. The decomposition temperature of A2CuCl4 slightly increased with the length of the aliphatic chain in the cation. The formation enthalpies of these compounds were determined by calorimetry, and the relationship between the layer shift parameter (S) and the reaction enthalpy was analyzed.