Naslov
Dehalogenation of Chloroalkenes at Cobalt Centers. A Model Density Functional Study

Autori
Bu¨hl, Michael ; Vinković Vrček, Ivana ; Kabrede, Hendrik

Izvornik
Organometallics (0276-7333) 26 (2007), 6; 1494-1504

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
chloroalkenes; cobalt; DFT; dehalogenation; vitamin B12; cobaloximes

Sažetak
Reaction of a model cobaloxime, MeCo(Hgly)2(NHCH2) (Hgly ) glyoximato), with chloro ethenes ClX1CdCX2X3 (X ) Cl or H) under reductive conditions has been investigated at the BP86 level of density functional theory. Initial one-electron reduction of the metal complex affords either [MeCo(Hgly)2]¥ ; ; ; ; - or [Co(Hgly)2(NHCH2)]-. Both can react with the substrates under chloride elimination to form the corresponding vinylcobalt complexes with a Co-CX1dCX2X3 moiety, which is indicated to be the ratelimiting step in a potential catalytic cycle. Free energies of activation on the order of 20 kcal/mol are predicted for these processes, suggesting that such an inner-sphere reduction (i.e., one that takes place in the coordination sphere of the metal) could be a viable pathway. Implications for the mechanism with functional biological systems based on vitamin B12 are discussed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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