Applications of P(III) compounds as promoters of Rf transfer reactions, organocatalysts and halogen bonded adducts

UoM administered thesis: Phd

  • Authors:
  • Sanaa Abushhewa

Abstract

The interaction between C4F9I and different phosphines in varying ratios has been investigated based on the chemical shift of the CF2I signal of C4F9I. The 31 P and 19F NMR chemical shifts were compared to those of PR3 and C 4F9I over a range of different concentration of phosphine for a fixed amount of C4F9I. It was found PCy 3 and P(n-Bu)3 resulted in the largest difference in chemical shift values of the CF2 I signal. Tri-n-butyl phosphine was investigated as an activator in the reaction of perfluoro-1- iododecane with Ph2PPPh2. Having prepared Ph2PC10F21 some of its reactions were studied, such as with xenon difluoride to give Ph2PF2C10F21, and selenium to form Ph2 P(Se)C10F21. In a similar way Ph2PC12F25 was prepared along with its compounds Ph2PF2C12F25, Ph2P(O)C12F25 and Ph2P(Se)C12F25. The X-ray crystal structures of Ph2PC10F21 and Ph2PF2C10F21 have been obtained. P(n-Bu)3 has been identified as a good phosphine organocatalyst for Ruppert reagent reactions and a series of reactions between aromatic aldehydes and CF3SiMe 3 were undertaken. The X-ray crystal structures of the NpCH(OSiMe 3)(CF3) (Np = naphthyl) and (2,6-F2C6 H3)CH(OH)CF3 prepared in this way are reported. This methodology was extended to the commercially available RfSiMe3 (Rf = C2F5, C3F7) to give a number of new Rf -containing compounds. When using n-C3F 7SiMe3 a mixture of products containing i-C3F7 and n-C3F7 fragments were observed. For this reason a number of different methods of introducing Rf groups were investigated, based on halogen-bonded R fI reagents. In this way it proved possible to successfully transfer a wide range of Rf groups, such as C3F7, C4F9, C5F11,C6F13, in to a variety of aldehydes. This method has a number of advantages compared with using the Ruppert reagents, including a wider range of Rf groups and no observed isomerisation of the Rf group being introduced.

Details

Original languageEnglish
Awarding Institution
Supervisors/Advisors
Award date1 Aug 2018