Increased Coordination via Sulfur Donor Action in Cyclic Pentaoxyphosphoranes and the Parent Cyclic Phosphite. Influence of Pentafluorophenoxy Ligands(1)

Paul Sood; A. Chandrasekaran; Roberta O. Day; Robert R. Holmes

doi:10.1021/ic971593q

Increased Coordination via Sulfur Donor Action in Cyclic Pentaoxyphosphoranes and the Parent Cyclic Phosphite. Influence of Pentafluorophenoxy Ligands(1)

Inorg Chem. 1998 Jul 27;37(15):3747-3752. doi: 10.1021/ic971593q.

Authors

Paul Sood¹, A. Chandrasekaran, Roberta O. Day, Robert R. Holmes

Affiliation

¹ Department of Chemistry, Box 34510, University of Massachusetts, Amherst, Massachusetts 01003-4510.

PMID: 11670474
DOI: 10.1021/ic971593q

Abstract

The pentafluorophenoxy ligand was introduced into the new cyclic pentaoxyphosphoranes S[(t-Bu)MeC(6)H(2)O](2)P(OC(6)F(5))(O(2)C(6)Cl(4)) (1), S[(t-Bu)MeC(6)H(2)O](2)P(OC(6)F(5))(O(2)C(14)H(8)) (2), and S[(t-Bu)MeC(6)H(2)O](2)P(OC(6)F(5))(3) (3). X-ray analysis revealed hexacoordinate structures formed by sulfur donor action present as a bridging atom in flexible eight-membered rings for 1-3. X-ray analysis showed that sulfur coordination also occurred with the same type of ring system as part of the phosphite S[(t-Bu)MeC(6)H(2)O](2)P(OC(6)F(5)) (4) to give a pseudo-trigonal-bipyramidal geometry. The pentafluorophenoxy ligand present in the oxyphosphoranes 1-3 as well as in the phosphite 4 acts comparably to a chlorine atom in its ability to enhance phosphorus electrophilicity as measured by the degree of P-S coordination and geometrical displacement toward a more highly coordinated state. The phosphite 4 has a P-S donor distance of 2.876(2) Å, considerably longer than the range of P-S distances from 2.366(3) to 2.495(2) Å obtained for the pentaoxyphosphoranes 1-3. These data express quantitatively the relative electrophilicity of phosphorus as a function of coordination number and substituent composition.