Dimolybdenum Perfluorotetrabenzoate and Silver Perfluorocyclohexanoate: Synthesis, Evaporation, and Thermodynamic Characteristics

Abstract

Anhydrous dimolybdenum perfluorotetrabenzoate Мо₂(ООСС₆F₅)₄ (I) and silver perfluorocyclohexanoate AgOOCC₆F₁₁ (II) are synthesized for the first time. Complex I is synthesized by the transcarboxylation of dimolybdenum tetraacetate with pentafluorobenzoic acid. Compound II is synthesized from freshly prepared silver oxide and perfluorocyclohexanoic acid. The evaporation of the complexes is studied by the Knudsen method with mass spectral analysis of the gas phase. The sublimation of Мо₂(ООСС₆F₅)₄ is congruent. The enthalpy of sublimation and the equation of the temperature dependence of the vapor pressure are found. The evaporation of AgOOCC₆F₁₁ is accompanied by the complete thermal decomposition with the formation of Ag(s) and mainly С₆F₁₂, С₆F₁₀, and CO₂ molecules. The standard enthalpies of thermal decomposition (\({{\Delta }_{r}}H_{{298.15}}^{^\circ }\)(5) = 439.5 ± 16.4 kJ/mol, \({{\Delta }_{r}}H_{{298.15}}^{^\circ }\)(6) = 325.2 ± 14.0 kJ/mol) and formation of the silver complex (\({{\Delta }_{f}}H_{{298.15}}^{^\circ }\) (AgOOCC₆F₁₁, c) = –2751.0 ± 24.4 kJ/mol) are determined.