Catalytic Dehydropolymerisation of Amine– and Phosphine–Boranes as a Route to Structurally Diverse Materials

Abstract

This thesis describes the synthesis and characterisation of polyamino– and
polyphosphinoboranes, targeting the use of catalytic dehydropolymerisation as a route to
obtain polymers with varied structures.
Chapter 1 puts into context of the area of metal-catalysed dehydrocoupling chemistry of
main group compounds with an emphasis on amine– and phosphine–boranes as
precursors to polymeric materials, and the properties and potential applications of the
related inorganic polymers.
Chapter 2 describes the synthesis of a family of aryl-substituted phosphine–boranes with
electron-donating and electron-withdrawing groups and the polymerisation of these
monomers by metal-catalysed dehydropolymerisation using [CpFe(CO)2OTf] as a
precatalyst. The discussion focuses on the influences of the electronics of the substituents
in the side chains on the properties of the polymers, and the study of their thermal
properties, as well as their potential applications.
Chapter 3 describes the expanded use of [CpFe(CO)2OTf] as a versatile precatalyst for the
dehydropolymerisation of a range of alkyl-substituted phosphine–boranes with varied
structures. Although preliminary investigation was hampered by monomer purity, the
discussion focuses on the potential factors that could affected the monomer’s reactivity.
The thermal properties of poly(alkylphosphinoboranes) are also discussed.
Chapter 4 presents the use of amine–boranes substituted by aryl-containing alkyl groups
at nitrogen via catalytic dehydropolymerisatiom aided by transition metal precatalysts.
The formation of high molar mass homopolymers and copolymers is described along with
thermal stability and cross-linking studies. Discussion on the molar mass characterisation
of polyaminoboranes by different analytical techniques is also described.
Chapter 5 describes the unprecedented synthesis and characterisation of the BN inorganic
analogues of polystyrene, poly(B-arylaminoboranes) through metal-catalysed
dehydropolymerisation of B-substituted amine–boranes. In addition, the stability studies
in the solid state and in solution for these polymers is presented.
Chapter 6 presents ongoing and potential ideas for future work based upon the results
presented in Chapter 2–5.

Date of Award	23 Jan 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Ian Manners (Supervisor)