Streamlined Preparation and Coordination Chemistry of Hybrid Phosphine–Phosphaalkene Ligands

• Published in: Organometallics Vol. 35; no. 6; pp. 855 - 859
• Main Authors: Magnuson, Kevin W, Oshiro, Shelly M, Gurr, Joshua R, Yoshida, Wesley Y, Gembicky, Milan, Rheingold, Arnold L, Hughes, Russell P, Cain, Matthew F
• Format: Journal Article
• Language: English
• Published: American Chemical Society 28-03-2016
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/acs.organomet.6b00101

A rationally designed and selective synthesis of hybrid phosphine–phosphaalkene ligands E -1a (Cy2PCH2CHPMes*, Mes* = 2,4,6-tri-tert-butylphenyl) and E -1b (Ph2PCH2CHPMes*) was developed using phospha-Wittig methodology. The new hybrid ligands E -1a and E -1b were used to prepare the Pd and Pt dichloride complexes Pd­(Cy2PCH2CHPMes*)­Cl2 (2a), Pd­(Ph2PCH2CHPMes*)­Cl2 (2b), Pt­(Cy2PCH2CHPMes*)­Cl2 (3a), and Pt­(Ph2PCH2CHPMes*)­Cl2 (3b). The crystal structures of E -1a, E -1b, 2a·1.33CHCl3, 3a·CH3CN, and 3b were determined. DFT calculations (M06/LACV3P**) on 2a revealed that the π* orbital located on the PC unit is low-lying and accessible. An NBO analysis concluded that the phosphaalkene ligand is a significantly poorer σ donor and a slightly better π acceptor than its tertiary phosphine counterpart, due to the presence of the PC double bond.