Metal carbonyl complexes of phosphaamidines. Coordinative integrity detected in C-amino(λ(3),σ(2))-phosphaalkene isomers coordinated through n(P) HOMO-1 donor orbitals.
Metal(0) complexes L(Cr,Mo,W)(CO)5 have been prepared from 1,3-bis(2,6-diisopropylphenyl)-2-(4-methylphenyl)-3-aza-1(λ(3),σ(2))-phosphapropene and 1,3-bis(2,6-diisopropylphenyl)-2-(4-methoxyphenyl)-3-aza-1(λ(3),σ(2))-phosphapropene using standard methods. Full characterization of four products and crystal structures of these complexes as well as the methoxyphenyl-phosphapropene are reported. The ligands coordinate κP, common for simple phosphaalkenes, despite the strongly-perturbing amino substitution at the double bond C atoms. Analyses of the NMR and vibrational spectroscopic data reveal that the complexes have very similar character to similarly-coordinated phosphaalkenes, with strong σ-donor character. The presence of some net π-interactions (acceptor or donor) is indicated by structures in which the ligands coordinate fully eclipsed with the M-CO groups. The synthetic and structural results have been augmented by B3PW91/LANL2DZ calculations that reproduce the structures of the Cr complexes accurately. The calculated vibrational spectra are used to confirm the assignment of the ν(C ≡ O) vibrational data. Detailed orbital interaction diagrams based on DFT calculations are reported for the title complexes as well as for the Cr(CO)5 complex of Mes-P=CPh2. The electronic absorption spectra of the title complexes have intense low-energy absorptions ranging from 24,500 to 25,300 cm(-1), which can be interpreted qualitatively using the DFT results.
Department of Chemistry, Saint Mary's University, Halifax, Nova Scotia, CanadaB3H 3C2.
Jason D
JD
Masuda
René T
RT
Boeré