Thermochemistry of the ternary complex Eu(Et 2dtc) 3(phen)

Abstract

A ternary solid complex Eu(Et 2dtc) 3(phen) has been obtained the from reaction of sodium diethyldithiocarbamate (NaEt 2dtc), 1,10-phenanthroline (phen) and hydrated europium chloride in absolute ethanol. The title complex was described by chemical and elemental analyses, TG-GTG and IR spectrum. The enthalpy change of liquid-phase reaction of formation of the complex, Δ r H m θ (l), was determined as−(13.481 ± 0.0314) kJ · mol −1 at T = 298.15 K by a RD-496 III heat conduction microcalorimeter. The enthalpy change of the solid-phase reaction of formation of the complex, Δ r H m θ (s), was calculated as (152.317 ± 0.542) kJ · mol −1 on the basis of a designed thermochemical cycle and other auxiliary thermodynamic qualities. The thermodynamics of reaction of formation of the complex was investigated by changing the temperature of liquid-phase reaction. Fundamental parameters, the apparent reaction rate constant ( k), the apparent activation energy ( E), the pre-exponential constant ( A), the reaction order ( n), the activation enthalpy ( Δ H ≠ θ ), the activation entropy ( Δ S ≠ θ ), the activation free energy ( Δ G ≠ θ ) and the enthalpy ( Δ r H ≠ θ ), were obtained combination the reaction thermodynamic and kinetic equations with the data of thermokinetic experiments. The constant-volume combustion energy of the complex, Δ c U, was determined as −(17410.63 ± 8.95) kJ · mol −1by a RBC-Π rotating-bomb calorimeter at T = 298.15 K. Its standard enthalpy of combustion, Δ c H m θ , and standard enthalpy of formation, Δ f H m θ , were calculated to be −(17429.84 ± 8.95) kJ · mol −1 and −(1231.76 ± 9.92) kJ · mol −1, respectively.