The synthesis and characterisation of iron and tungsten organometallic polymers with metal-carbon sigma bonds

Abstract

A variety of olefinic organometallic monomers have been synthesised and polymerised under free-radical conditions. These monomers all contain a vinyl moiety as part of an organic fragment which is bonded via a metal-carbon a-bond to the metal centre. The monomers are generally compounds of the type [(ri 5-C5H5) M(CO)nRJ, where M = Fe, n = 2 and M = W, n = 3 and R represents an alkyl, acyl or aryl group containing the vinyl functionality. The known complexes prepared in this study include those where M = Fe, R = -(CH2)CH=CH2 (I), -COCH=CH2 (11), -COCH=CHPh (ill) and the tungsten complex (ri 5-C 5H5)(CO)3WCOCH=CHPh (VII). The new olefinic monomers include those where M = Fe, R = -COC6H4CH=CH2 (IV), -C6H 4CH=CH2 (V) and the tungsten complex (ri 5-C5H5)(CO)3WCOC6H4CH=CH2 (Vill). The new pentamethylcyclopentadienyl analogue,(17 5-C 5Me5)(CO)2FeCOC6H4CH=CH2 (V) was also prepared in this study. All of the monomers have been fully characterised using analytical techniques such as IR, 1H NMR and 13 C NMR spectroscopy, microanalysis and mass spectrometry. Homopolymerisation and copolymerisation studies of the prepared organometallic monomers were conducted using multiple re-initiations with the free-radical catalyst 2,2'azobisisobutyronitrile (AIBN). The polymers were characterised by IR, and 1H NMR spectroscopy. Their properties were studied by other available techniques including Differential Scanning Calorimetry, Thermogravimetric Analysis, Scanning Electron Microscopy and Gel Permeation Chromatography. The results obtained for some of these polymers are discussed.