Streamlined Preparation and Coordination Chemistry of Hybrid Phosphine–Phosphaalkene Ligands
作者:Kevin W. Magnuson、Shelly M. Oshiro、Joshua R. Gurr、Wesley Y. Yoshida、Milan Gembicky、Arnold L. Rheingold、Russell P. Hughes、Matthew F. Cain
DOI:10.1021/acs.organomet.6b00101
日期:2016.3.28
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*)Cl-2 (2a), Pd(Ph2PCH2CH=PMes*)Cl-2 (2b), Pt(Cy2PCH2CH=PMes*)Cl-2 (3a), and Pt(Ph2PCH2CH=PMes*)Cl-2 (3b). The crystal structures Of E-1a, E-1b, 2a.1.33CHCl(3), 3a.CH3CN; and 3b were determined. DFT calculations (M06/LACV3P**) on 2a revealed that the pi* orbital located on the P=C unit is low-lying and accessible. An NBO analysis concluded that the phosphaalkene ligand is a significantly poorer sigma donor and a slightly better pi acceptor than its tertiary phosphine counterpart, due to the presence of the P=C double bond.