The synthesis of new perfluoroalkenyl phosphines and their use in catalysis

  • Hana Ghaba

Student thesis: Phd

Abstract

Exhaustive deprotonation of CF3CFH2 (HFC-134a) by two equivalents of nBuLi at low temperature gives LiCF=CF2. Immediate low temperature quench with a diethyl ether solution of RPCl(R=Ph) at low temperature affords bis substituted perfluorovinyl phosphines RP(CF=CF2)2 in excellent yield after distillation or column chromatography. This thesis reports an investigation into the reactions of HFCs of the type RfCF2CH2F to longer-chain perfluoroalkenyl phosphines. The reactivity of a range of commercially available hydrofluorocarbons toward n-butyllithium has been explored as a means of generating novel fluoroalkenyllithium reagents. This has led to the discovery of a new and versatile route from CF3CF2CH2F (HFC-236) under mild conditions for the synthesis of a wide range of novel perfluoropropenyl-containing phosphines PR2(CF3CF=CF2) and PR2(CF3CF=CF2) (R= Ph, iPr , Me). The reaction of HFC-1225y (Z-CF3CF=CFH) with base and subsequently with R2PCl and RPCl2 also generates perfluoropropenyl containing phosphines, including tBuP(CF=CF(CF3))2. These phosphine have been oxidised by H2O2, sulfur and selenium to yield P(V) analogues. Single crystal X-ray structural analysis of iPrP(Se) (CF=CF(CF3)) is reported. The perfluoroalkenyl phosphines PR2(CF3CF=CF2)and PR2(CF3CF=CF2) (R= Ph , iPr , Me) have been coordinated to Pd(II), Pt(II), Au(I) and Rh(I) metal centres. [PtCl2{Ph2P(CF=CFCF3)}2], [PdCl2{iPr2P(CF=CFCF3)}2] and [AuCl{PhP(CF=CFCF3)2}] have been crystallographically characterised; the first examples of metal complexes containing a perfluoropropenyl phosphine. The application of these phosphines to Heck and Suzuki coupling reactions have also been investigated, with Ph2P(CF=CF(CF3)) being the most successful phosphine in both systems.
Date of Award1 Aug 2015
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorAlan Brisdon (Supervisor)

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