Wydział Chemii

Sławomir Berski

F. Sensato

Victor Polo

Juan Andrés

V. S. Safont

2011

Journal of Physical Chemistry A

115

514-522

10.1021/jp108440f

Naukowa

Angielski

Artykuł

The oxygen atom transfer reaction from the Mimoun-type complex MoO(η²-O₂)₂OPH₃ to ethylene C₂H₄ affording oxirane C₂H₄O has been investigated within the framework of the Bonding Evolution Theory in which the corresponding molecular mechanism is characterized by the topological analysis of the electron localization function (ELF) and Thom’s catastrophe theory (CT). Topological analysis of ELF and electron density analysis reveals that all Mo−O bonds in MoO(η²-O₂)₂OPH₃ and MoO₂(η²-O₂)OPH₃ belong to closed-shell type interactions though negative values of total energy densities E^e(r_BCP) imply some covalent contribution. The peroxo O_i—O_j bonds are characterized as charge-shift or protocovalent species in which pairs of monosynaptic basins V₃(O_i), V₃(O_j) with a small electron population of ∼0.25e each, are localized between core basins C(O_i), C(O_j). The oxygen transfer reaction from molybdenum diperoxo complex MoO(η²-O₂)₂OPH₃ to C₂H₄ system can be described by the following consecutive chemical events: (a) protocovalent peroxo O₂−O₁ bond breaking, (b) reduction of the double C₁═C₂ bond to single C₁−C₂ bond in ethylene, (c) displacement of oxygen O₁ with two nonbonding basins, V_i=1,2(O₁), (d) increase of a number of the nonbonding basins to three (V_i=1,2,4(O₁)); (e) reorganization and reduction in the number of nonbonding basis to two basins (V_i=1,4(O₁)) resembling the ELF-topology of the nonbonding electron density in oxirane, (e) formation of the first O₁−C₂ bond in oxirane, (f) C₂−O₁—C₂ ring closure, (g) formation of singular nonbonding basin V(O₂) in new Mo═O₂ bond. The oxygen atom is transferred as an anionic moiety carrying a rather small electronic charge ranging from 0.5 to 0.7e.

https://doi.org/10.1021/jp108440f

https://www.acs.org/content/acs/en.html