Thermodynamic Study of (Hexafluoroacetylacetonato)(cyclooctadiene-1,5)copper As the Technological Basis for the Development of Chemical Vapor Deposition of Metal-Containing Film Heterostructures

New data on the thermal behavior, sublimation, and melting of (hexafluoroacetylacetonato)(cyclooctadiene-1,5)copper, [Cu(cod)(hfac)], have been obtained. The condensed phase was studied by thermal and differential thermal analysis and differential scanning calorimetry. The temperature, enthalpy, and entropy of melting of the complex were determined. The temperature dependence of the saturated vapor pressure of [Cu(cod)(hfac)] in the temperature range 293–337 K was obtained by the Knudsen effusion method with mass spectrometric recording of the gas phase composition. The thermodynamic characteristics of sublimation were calculated at the average temperature over the experimental range and at 298.15 K: \({{{{\Delta }}}_{{{\text{subl}}}}}H_{{\text{m}}}^{{\text{o}}}\) (T_av) = 94.8 ± 1.5 kJ mol^–1; \({{{{\Delta }}}_{{{\text{subl}}}}}S_{{\text{m}}}^{{\text{o}}}\) (T_av) = 200.9 ± 3.2 J mol^–1 K^–1; \({{{{\Delta }}}_{{{\text{subl}}}}}H_{{\text{m}}}^{{\text{o}}}\) (298.15 K) = 95.8 ± 3.1 kJ mol^–1; \({{{{\Delta }}}_{{{\text{subl}}}}}S_{{\text{m}}}^{{\text{o}}}\) (298.15 K) = 203.5 ± 6.6 J mol^–1 K^–1. The obtained values are compared with data for a similar iridium(I) compound, [Ir(cod)(hfac)]. The results were used formulate approaches to evaluation of the thermodynamic properties of [M(cod)(hfac)] complexes to determine the optimum conditions for the deposition of metal-containing coatings. These approaches are necessary in those cases when compounds of this type (e.g., [Ag(cod)(hfac)]) are hypersensitive to heating and it is impossible to determine reliable thermodynamic characteristics experimentally.