Vinylidene carbonylation at a manganese-iron complex: A density functional study of mechanism

Treating the phenylvinyldene manganese complex Cp(CO)(2)Mn=C(1)=C(2)HPh, 1, with [Fe(CO)(4)] yields the binuclear mu-vinylidene complex Cp(CO)(2)MnFe(mu-C(1)=C(2)HPh)(CO)(4), 2, that further isomerizes to the carbonylated product eta(4)-[Cp(CO)(2)MnC(1)(CO)C(2)HPh]Fe(CO)(3), 3. In a computational study of the mechanism using a hybrid density functional method, we considered two stereoisomers for species 2 and 3 where the phenyl group at center C(2) is oriented in cis (E form) or trans (Z form) fashion to the Cp(CO)(2)Mn unit. Isomers 2E and 2Z were calculated to be degenerate whereas the experimentally detected species 3E is 8 kcal/mol more stable than its isomer 3Z. The two-step pathway 1 -> 2Z -> 3E was calculated to be the lowest-energy route with the highest activation barrier at 12 kcal/mol. The activation energy of the alternative single-step pathway 1 -> 3E is 19 kcal/mol. We rationalized the stabilization of the ground state of 3E and the transition states leading to or starting from isomer 2Z as conjugation effect between the Mn-C=C metallaallene fragment and the co-planar phenyl ring. (C) 2011 Elsevier B. V. All rights reserved.     «

Treating the phenylvinyldene manganese complex Cp(CO)(2)Mn=C(1)=C(2)HPh, 1, with [Fe(CO)(4)] yields the binuclear mu-vinylidene complex Cp(CO)(2)MnFe(mu-C(1)=C(2)HPh)(CO)(4), 2, that further isomerizes to the carbonylated product eta(4)-[Cp(CO)(2)MnC(1)(CO)C(2)HPh]Fe(CO)(3), 3. In a computational study of the mechanism using a hybrid density functional method, we considered two stereoisomers for species 2 and 3 where the phenyl group at center C(2) is oriented in cis (E form) or trans (Z form) f...     »

ISI Document Delivery No.: 831GM Times Cited: 0 Cited Reference Count: 51 Shor, Elena A. Ivanova Nasluzov, Vladimir A. Shor, Aleksey M. Antonova, Alla B. Roesch, Notker Presidium of the Russian Academy of Sciences [7.18]; Fonds der Chemischen Industrie (Germany) We thank Andreas Heyden for providing his DIMER program for use in this project. This work was supported by the Presidium of the Russian Academy of Sciences (Program for Basic Research, Project No. 7.18) and Fonds der Chemischen Industrie (Germany). 0 Elsevier science sa Lausanne     «

ISI Document Delivery No.: 831GM Times Cited: 0 Cited Reference Count: 51 Shor, Elena A. Ivanova Nasluzov, Vladimir A. Shor, Aleksey M. Antonova, Alla B. Roesch, Notker Presidium of the Russian Academy of Sciences [7.18]; Fonds der Chemischen Industrie (Germany) We thank Andreas Heyden for providing his DIMER program for use in this project. This work was supported by the Presidium of the Russian Academy of Sciences (Program for Basic Research, Project No. 7.18) and Fonds der Chemischen Industr...     »