[N-ALKYL-(2-PYRIDYL)METHANIMINE]COPPER(I) COMPLEXES - CHARACTERIZATION AND APPLICATION AS CATALYSTS FOR ATOM-TRANSFER POLYMERIZATION

The synthesis and characterisation of a series of novel bis(imine)copp er(I) complexes and their use in atom-transfer polymerisation of methy l methacrylate is described. Several N-alkyl-(2-pyridyl)methanimines ( alkyl = n-butyl, isobutyl, sec-butyl, n-propyl) and N-(n-propyl)-1-(2- pyridyl)ethanimine as ligands have been fully characterised. Three bis [N-alkyl-(2-pyridyl)methanimine]copper(I) complexes, [Cu{(C5H4N)CH=N(i Bu)}(2)][BF4], [Cu{(C5H4N)C(CH3)=N-(nPr)}(2)][PF6], and [Cu{(C5H4N) CH =N(sBu)}(2)][BF4] have been structurally characterised; all having a d istorted tetrahedral arrangement of co-ordinating nitrogen atoms surro unding the metal centre. All of the catalysts were found to be effecti ve atom-transfer polymerisation catalysts for the polymerisation of MM PI in hydrocarbon solution. However, it was discovered that the perfor mance of the catalysts containing n-alkyl substituents was superior to those containing branched alkyl substituents. The presence of branchi ng in the alkyl substituent results in a reduction of reaction rate an d a corresponding broadening of the polydispersity index.