| Abstract
| - Polymer microstructures obtained by copolymerizations of (Z)-1,3-pentadiene with ethene,conducted at different temperatures by the CpTiCl3−MAO catalytic system, have been characterized bydetailed 13C NMR analyses. The observed microstructures indicate an essential role of the backbiting ofthe allyl-terminated growing chain on the occurrence of 1,2 syndiotactic and 1,4-cis high selectivities,which are observed for (Z)-1,3-pentadiene homopolymerizations at low and high temperatures, respectively.Molecular modeling studies suggest that the occurrence of 1,2-syndio and 1,4-cis stereoselectivities wouldbe determined by the steric constrain (and stereorigidity) associated with the maintenance, in monomerbound intermediates, of the backbiting coordination of syn and anti allyl-terminated growing chains,respectively.
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