Theoretical study of thermal rearrangements of 2-alkylidenecyclopenta-1,3-diyl biradicals

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2011

Öğrenci: UĞUR BOZKAYA

Danışman: İLKER ÖZKAN

Özet:

Thermal rearrangements of Berson TMMs have been investigated. For this purpose, the potential energy surface of the singlet S state has been explored to test Benson’s Schemes 1-2 (Figure 1.10 and 1.11). It is verified that the enyne 9c plays a central role in connecting the two portions of the reaction path (Berson Schemes 1 and 2). Connectivity of successive minima on a given surface has been verified by intrinsic reaction coordinate (IRC) computations. Density functional theory (DFT) and multiconfiguration self consistent field (MCSCF) methods have been employed for these purposes. Further, single point coupled-cluster singles and doubles with perturbative triples (CCSD(T)) energy computations have been carried out at optimized DFT or MCSCF geometries. All transition states (TS) connecting each neighboring minimum have been located in the proposed mechanisms. It is concluded that the proposed mechanisms are confirmed by the theoretical calculations. The computed activation energy and enthalpy of reaction values are in good agreement with the available experimental values, only differing by a few kcal mol-1.