Naslov
DFT Study of Cyclopalladation Mechanism of Benzylamines

Autori
Babić, Darko ; Ćurić, Manda ; Smith, David M.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
XXII International Conferenceon Organometallic Chemistry : Actas del Congreso / - Zaragoza, 2006

Skup
XXII International Conferenceon Organometallic Chemistry

Mjesto i datum
Zaragoza, Španjolska, 23.07.2006. - 28.07.2006

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
benzylamines; palladium acetate; cyclopalladation; mechanism; ab initio

Sažetak
Cyclopalladation of benzylamine (BA) may be considered as a prototype for a wide variety of orthometalation reactions. There are numerous experimental studies of this reaction with various palladium sources, ligands and solvents [refs]. Different mechanisms have been proposed on the basis of experimental results [refs]. Yet, it was only recently [ref] that the mechanism of this reaction was investigated by quantum-chemical methods. However, as the reacting complex (BA-Pd(OAc)2) employed in that study has a considerably higher energy than other possible species that could exist in solution, a more comprehensive approach is required. Here, we present the results of DFT (B3LYP/6-31G**, SDD) calculations for cyclopalladation reactions starting from several (more stable) reacting species: [BA-Pd-( -OAc)2]2, BA-[Pd-( -OAc)2]2-NCMe, BA-Pd(OAc)2-BA and BA-Pd(OAc)2-NCMe. In all cases considered, the agostic character of the mechanism reported in [ref] was confirmed. However, instead of the six-membered transition state, only four-membered ones were found to be feasible. The barrier heights of the critical step (hydrogen transfer) with reacting species different from the one assumed in [ref] vary between 26.45 and 36.3 kcal/mole, while for BA-Pd(OAc)2 it amounts to 18.3 kcal/mole. Although the energies required for the four-membered transition states are higher, the greater stability of the reacting species makes these mechanisms more realistic than the mechanism involving the reactive BA-Pd(OAc)2. In addition, the possibility that the specific reaction mechanism depends on factors such as the concentration ratio of Pd and ligand, as well as the solvent, should not be neglected.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

Napomena
Zbog potpunosti zapisa, molim SVE podatke o zborniku, admin (2007-06-06)

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