SYNTHESIS AND PROPERTIES OF TRIS(2,4,6-TRIMETHOXYPHENYL)PHOSPHINE ANDTRIS(2,4,6-TRIMETHOXYPHENYL)PHOSPHINE OXIDE

The functionalized triaryl phosphine tris(2,4,6-trimethoxyphenyl)phosp hine (TMPP) was prepared and characterized by single crystal X-ray dif fraction studies and multinuclear NMR spectroscopy. The asymmetric uni t contains two independent molecules of TMPP on general positions that adopt a pseudo-propeller arrangement of the arene substituents. The b asicity of TMPP was evaluated by measuring the nu(Al)(CO) stretching m ode for the complex Ni(CO)3L; the value for Ni(CO),TMPP is nu(Al)(CO) = 2048 cm-1, which is the lowest reported value for a tertiary phosphi ne complex (PR3)Ni(CO)3. The phosphine oxide derivative, tris(2,4,6-tr imethoxyphenyl)phosphine (TMPP=O), was prepared by oxidation with H2O2 in refluxing acetone. In the structure of TMPP=O, the oxygen atom of the phosphine oxide is hydrogen bonded to two interstitial water molec ules. Both the phosphine and phosphine oxide compounds were fully char acterized by a variety of physical and spectroscopic techniques, inclu ding NMR (H-1, P-31, C-13), IR and electronic absorption spectroscopie s and cyclic voltammetry.