Structural displacement of phosphites, phosphates, and pentaoxyphosphoranes to higher coordinate geometries by sulfur and oxygen donor action

New phosphites, O2S [(t-Bu)MeC6H2O](2)P(OC6F5)(1), S[Me2C6H2O](2)P(OC6F5) ( 3), and H2C[(t-Bu)(2)C6H2O](2)P- (OC6F5) (6), a phosphate, S[(t-Bu)MeC6H2O] (2)P(O)(OC6F5) (4), and pentaoxyphosphoranes O2S [(t-Bu)MeC6H2O](2)P-(OC6F5 )(O2C6Cl4) (2) and S[Me2C6H2O](2)P(OC6F5)(3) (5), all containing pentafluor ophenoxy Ligands, have been prepared and characterized by NMR and X-ray stu dies. Starting with either PCl3 for the phosphites or POCl3 for the phospha te, reactions with diols formed cyclic chlorophosphites or a chlorophosphat e, respectively, in situ, followed by condensation with pentafluorophenol t o give the products. An oxidative addition reaction of I with a quinone pro duced 2 while 5 was prepared from P(OC6F5)(3) formed in situ, followed by o xidative addition with a diol. Other than 6, all contained sulfonyl (1 and 2) or sulfur (3-5) donor groups which coordinated with phosphorus to give p seudo trigonal bipyramidal (1 and 3), trigonal bipyramidal (4), and octahed ral (2 and 5) geometries. In the presence of OC6F5 ligands, the sulfur atom and oxygen atom of the sulfonyl group exercise similar donor abilities for oxyphosphoranes, which contrasts with previous studies where ligands of le sser electronegativity were employed that showed sulfur to supply stronger donor interaction in displacing oxyphosphoranes toward an octahedral geomet ry. This leveling effect is attributed to the enhancement of the electrophi licity at phosphorus in the presence of pentafluorophenoxy ligands. In supp ort of earlier work, it is now quantitatively well defined that donor actio n causes an increase in coordination geometry at phosphorus where the stren gth of such action increases in the order phosphates < phosphites < oxyphos phoranes.