Complexes between cyclopentene and cyclopentyne derivatives with HCu and FCu. The importance of cyclization effects

International Journal of Quantum Chemistry

5 years ago

Complexes between cyclopentene and cyclopentyne derivatives with HCu and FCu. The importance of cyclization effects

Manuel Yáñez, Al Mokhtar Lamsabhi, Otilia Mó, Serra Arslancan

B3LYP/6-311+G(3df,2p)//B3LYP/6-31+G(d,p) density functional theory calculations show that cyclopentene and cyclopentyne derivatives yield very strong π-type complexes with HCu and FCu molecules. This interaction is so strong in the case of cyclopentyne derivatives that the complexes formed can be considered as a new kind of metallocycles. These complexes resemble those reported before in the literature for ethylene and acetylene, though whereas the interaction energies between cyclopentene and HCu and FCu are smaller than those reported for ethylene, those involving cyclopentyne are larger than the ones calculated for acetylene. This very different behavior is due to the dramatic change in the local environment of the two carbon atoms of cyclopentyne with respect to acetylene, which does not occur on going from ethylene to cyclopentene. The introduction of heteroatoms in the five-membered rings opens the possibility of forming other isomers in which the CuX (X = H, F) is attached to the heteroatom rather than to the unsaturated CC bond. This arrangement is precisely the most favorable one for cyclopentene derivatives, though for cyclopentyne ones the π-type complexes are still the global minima. The complexes between HCu (FCu) and cyclopentene or cyclopentyne derivatives can be considered a new kind of metallocycles which may help to understand the role of HCu (FCu) in homogeneous catalysis.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/qua.25489