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RESEARCH PRODUCT

Die kinetik der allendimerisation, ein beitrag zum mechanismus

Alfred RoedigN. Detzer

subject

DiradicalAlleneOrganic ChemistryPhotochemistryBiochemistryCycloadditionChemical kineticschemistry.chemical_compoundParamagnetismMonomerchemistryGeneral theoryComputational chemistryThermal instabilityDrug Discovery

description

Zusammenfassung The reaction kinetics of the dimerization of some polyhalogenated allenes with the general formula Cl2CCCCIX (X = Cl, Br, C6H5, COOEt) and of tetrabromoallene was studied by an IR spectrophotometric method. The reaction was found to be of strictly second order kinetics. The activation parameters were determined and the experimental data and the influence of the substituents were discussed in terms of the accepted general theory of allene cycloaddition. All data are in agreement with a non-concerted two-step electrocyclic addition mechanism. Within the experimental limits no paramagnetic species like a diradical could be detected by the ESR-method during the dimerization reaction of tetrachloroallene. Finally, an attempt was made to explain the extreme thermal instability of all polyhalogenated allenic monomers.

https://doi.org/10.1016/s0040-4020(01)91734-x