Isopropyl-N-Aryl-Substituted Iminopyridine Iron Complex-Based Catalyst for the Polymerization of 1,3-Dienes: Influence of the Monomer Structure on the Regio-selectivity.

The polymerization of some 1,3-dienes (i.e., butadiene, isoprene and myrcene) with the catalyst system obtained by combining the imino-pyridine iron complex shown in Figure 1 with methylaluminoxane was examined.1 The polymers were characterized by FT-IR and NMR (1H, 13C and 2D), and were found to exhibit different structure depending on the monomer structure: an essentially syndiotactic 1,2 polymer from butadiene, a predominantly alternating cis-1,4-alt-3,4 polymer containing short cis-1,4 sequences (three units) along the polymer chain from isoprene, and finally an alternating cis-1,4-alt-3,4 polymer containing longer cis-1,4 sequences (five units) along the polymer chain from myrcene, were obtained.