Physicochemical Characterization of New Octamethylferrocenylmethylenemalononitrile by Complementary Methods: UV-Visible Solvatochromism, Moessbauer Spectroscopy, Differential Scanning Calorimetry, and X-ray Structure Determination

摘要

(Octamethylferrocenylmethylene)malononitrile (dicyanoethenyl-octamethylferrocene) was synthesized by condensation of octamethylferrocene carbaldehyde with malononitrile. The visible positive solvatochromism of the new compound was studied in 33 solvents and discussed in terms of Kamlet-Taft's π~* and α scales. Temperature-dependent Moessbauer spectroscopy using a ~(57)Fe-enriched sample suggests that the onset of ring rotation of the tetramethyl Cp ring was not accompanied by a significant librational motion of the ring. The quadrupole splitting parameter went through a maximum at ～220 K suggesting a phase change in the solid. Differential scanning calorimetry showed two endotherms at 228 and 236 K. Single crystal X-ray structure determinations at different temperatures showed two kinds of disorder at 243 K, only one of which remained at 183 K. A reversible change of disorder was observed at 213 K.