Formation of [Cr(CO)x(Ph2PN(iPr)PPh2)]+ Structural Isomers by Reaction of Triethylaluminum with a Chromium N,N-Bis(diarylphosphino)amine Complex [Cr(CO)4(Ph2PN(iPr)PPh2)]+: An EPR and DFT Investigation
| Autor: | Kingsley J. Cavell, Lucia McDyre, Emma Carter, Andrew Jon Hallett, James Alexis Platts, Damien Martin Murphy, David M. Smith, William Fullard Gabrielli, Martin J. Hanton |
|---|---|
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Organometallics. 32:1924-1931 |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/om400029y |
| Popis: | The interaction of triethylaluminum (TEA) with a solution of the paramagnetic Cr(I) bis(phosphine) complex [Cr(CO)41][Al(OC(CF3)3)4] (1 = Ph2PN(iPr)PPh2) has been studied using EPR and DFT. It was found that the TEA is responsible for the complete removal of all CO groups from the [Cr(CO)41]+ complex, producing the [Cr(1-bis-η6-arene)]+, and this reaction occurs via a dominant pathway involving a series of [Cr(CO)x1]+ (x < 4) intermediates, consistently including the cis-[Cr(CO)31]+ complex (species A) and the “piano-stool”-type [Cr(CO)21]+ complex (species C). A further [Cr(CO)21]+ intermediate complex (labeled species D, which is a structural isomer of species C) was also identified experimentally, suggesting a second pathway for TEA activation may also be operative. All of these paramagnetic complexes have been characterized by CW EPR, and the spin Hamiltonian parameters were verified using DFT. The distribution and type of [Cr(CO)x1]+ intermediates formed were found to be very sensitive to the experimental conditions, including the quantity and manner of TEA addition, the temperature of activation, and the aging time of the solution. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|