The enthalpy of sublimation of diphenylacetylene from Knudsen effusion studies

Abstract

The enthalpy of sublimation of diphenylacetylene at 298.15 K, Δ g cr H ⊖ m(C 2(C 6H 5) 2] = 95.1 ± 1.1 kJmol −1, was derived from vapour pressure-temperature data, obtained with two different Knudsen effusion apparatus, and from heat capacity measurements obtained by differential scanning calorimetry. The molybdenum-diphenylacetylene bond dissociation enthalpy in Mo(η 5-C 5H 5) 2[C 2(C 6H 5) 2] was reevaluated as 115 ± 26 kJ mol −1, on the basis of the new value for Δ cr g H ⊖ m[C 2(C 6H 5) 2].