was heated to 150 °C in the solid state at ca. 0.01 mbar for 2 h, resulting in the partial sublimation of the solid material, and minor production of a high-boiling colorless oil. After cooling to ambient temperature, the residues were extracted into 1,2-C6H4F2 (3 × 5 mL), filtered, and the solution concentrated to ca. 5 mL.