Thermal Reactivity of Neutral and Oxidized Ferrocenyl-Substituted Enediynes
AbstractThe coupling of two equivalents of ethynylferrocene (2) with one equivalent of 1,2-diiodocyclohexene (1) and 1,2-diiodobenzene (4) using Sonogashira cross-coupling conditions led to 1,2-bis(ferrocenylethynyl)cyclohexene (3) and 1,2-bis(ferrocenylethynyl)benzene (5), respectively. At high temperatures enediynes 3 and 5 showed exothermic signals in differential scanning calorimetry (DSC) measurements, suggestive of intramolecular diradicaloid ring formation (Bergman (C1−C6) or Schreiner-Pascal (C1−C5) cyclizations). The oxidation of 3 and 5 to the mono-oxidized enediynes 3+ and 5+ decreased the onset temperatures drastically. Equally, 1-ferrocenylethynyl-2-(p-nitro-phenyl)ethynylbenzene (8) displayed a significant decrease in the onset temperature after oxidation to 8+. Because the insoluble nature of the polymeric material formed in the thermolysis of the oxidized enediynes prevented characterization, the origin of this drastic effect was studied by DFT. Contrary to expectations, one-electron oxidation does not lower the barrier for intramolecular cyclization. Rather, the computations suggest that the polymerization is initiated by a bimolecular process. View Full-Text
- Supplementary File 1:
Supplementary (PDF, 1202 KB)
Scifeed alert for new publicationsNever miss any articles matching your research from any publisher
- Get alerts for new papers matching your research
- Find out the new papers from selected authors
- Updated daily for 49'000+ journals and 6000+ publishers
- Define your Scifeed now
Cinar, M.E.; Morbach, G.; Schmittel, M. Thermal Reactivity of Neutral and Oxidized Ferrocenyl-Substituted Enediynes. Molecules 2014, 19, 18399-18413.
Cinar ME, Morbach G, Schmittel M. Thermal Reactivity of Neutral and Oxidized Ferrocenyl-Substituted Enediynes. Molecules. 2014; 19(11):18399-18413.Chicago/Turabian Style
Cinar, Mehmet E.; Morbach, Guido; Schmittel, Michael. 2014. "Thermal Reactivity of Neutral and Oxidized Ferrocenyl-Substituted Enediynes." Molecules 19, no. 11: 18399-18413.