Alex M. Heming

Atom transfer polymerisation with glucose and cholesterol derived initiators

Functionalised glucose and cholesterol have been used to synthesise a range of star and linear poly(methyl methacrylate) and poly(styrene) by atom transfer living polymerisation.

Ligand electronic effects on rates of copper mediated atom transfer radical cyclisation and polymerisation

Abstract The effect of different N -pentyl-2-pyridylmethanimine derivatives 2a – f upon the rate of copper(I) mediated atom transfer radical cyclisation (ATRC) of 5 and living atom transfer radical polymerisation (ATRP) of methylmethacrylate were investigated.

Atom transfer radical polymerisation (ATRP) of methyl methacrylate in the presence of radical inhibitors

Atom transfer radical polymerisation of methyl methacrylate mediated by copper(I) bromide, alkyl bromides and N-pentyl-2-pyridylmethanimine has been shown to be enhanced by the addition of substituted phenols, traditionally used as radical inhibitors.

Atom transfer polymerisation of methyl methacrylate : use of chiral aryl/alkyl pyridylmethanimine ligands; with copper(I) bromide and as structurally characterised chiral copper(I) complexes

The use ofchiral catalysts in the living radical polymerisation of methyl methacrylate via atom transfer polymerisation (ATP) has been investigated in an effort to control the stereochemistry of the polymer backbone. Two enantiomerically pure chiral catalysts have been prepared and used in the ATP of methyl methacrylate: the structurally characterised complex, bis[N-(1-phenylethyl)-2-pyridylmethanimine]copper() tetrafluoroborate, [Cu(C14H14N2)2 ][BF4 ], and the reaction product of copper() bromide with N-(1-cyclohexylethyl)-2-pyridylmethanimine, [Cu(C14H20N2)2 ][Br]. Both catalysts were found to be suitable for the ATP of methyl methacrylate in conjunction with either ethyl 2-bromo-2-methylpropanoate in xylene at 90 °C or 4-methoxybenzenesulfonyl chloride in diphenyl ether at 90 °C. The system yields polymer of relatively narrow polydispersity; however, the use of these chiral catalysts did not significantly affect the stereochemistry of the polymer backbone. This may be due to the chiral centre being too distant from the propagating site to exert any influence over the monomer addition step, or that the reaction proceeds via a completely free-radical mechanism. This is, however, the first time a discrete, structurally characterised copper complex has been used as an effective ATP catalyst. The bond lengths of the complexed ligand indicate the oxidation state of the copper to be +1 in the complex.

Novel polymers from atom transfer polymerisation mediated by copper(I) Schiff base complexes

The use of copper(I) Schiff base complex catalysed atom transfer polymerisation of methacrylates is described. The use of a range of functional and multi-functional initiators enables the synthesis of a range of functional and star polymers to be prepared under undemanding synthetic conditions. End capping with silyl enol ethers allows for ω-functional polymers. The combination of novel initiators, functional monomers and end capping allows an unprecedented array of macromolecular structures to be produced with limited need for protecting group chemistry.

Halogen exchange during atom transfer polymerisation of methyl methacrylate mediated by copper(I) N-alkyl-2-pyridylmethanimine complexes

Highly efficient exchange between the halogen arising from the copper(I) halide and the alkyl halide originating from the initiator occurs during atom transfer polymerisation of methyl methacrylate mediated by copper(I) N-alkyl-2-pyridylmethanimine complexes.

Copper diimine complexes: the synthesis and crystal structures of [Cu(C10H14N2)2(MeOH)][BF4], [Cu(C10H20N2)2]Br, [{(C10H14N2)CuBr(µ-OMe)}2(MeOH)] and [{(C10H20N2)CuBr(µ-OMe)}2]

The synthesis and structural characterisation of related novel copper-(I) and -(II) diimine complexes have been described and their application as catalysts for atom transfer polymerisation is noted. The unexpected formation of a methoxy bridged copper(II) diimine complex [{(C10H14N2)CuBr(µ-OMe)}2(MeOH)] 3 from the reaction of a copper(I) diimine complex with phenol is described. Compounds 3 and [{(C10H20N2)CuBr(µ-OMe)}2] 4 appear to be examples of a rare class of alkoxy bridged CuII complexes, with very few similar examples being crystallographically characterised previously.