Ethylene/4‐Methyl‐1‐pentene Copolymers by a “Constrained Geometry Catalyst”: Advances in 13 C NMR Assignment

Abstract Ethylene/4‐methyl‐1‐pentene (E/4M1P) copolymers were synthesized by [Me 2 Si( η 5 ‐Me 4 C 5 )‐( η 1 ‐N‐ t Bu)TiCl 2 ] and methylalumoxane (MAO) catalyst ( CG ) and analyzed by 13 C NMR. The low regio‐ and stereoregularity of CG leads to spectral multiplicities which can be ascribed not only to differences in comonomer sequences but also to the presence of regio‐ and stereoirregularities. The tendency of CG to give a nearly random comonomer distribution gives rise to so far undetectable alternating sequences. The complete set of assignments proposed allows a satisfactory characterization of variously microstructured E/4M1P copolymers and the evaluation of the amount of regioirregular sequences in addition to the full determination of dyad and triad copolymer composition.