NMR-STUDY OF THE PROPAGATION CENTER IN CATIONIC POLYMERIZATION OF N-BENZOYL-8-OCTANELACTAM .1. THE STRUCTURE OF MODEL LIVING OLIGOMERS

Model living oligomers of N-benzoyl-8-octanelactam initiated by the mo del octanoylium hexachloroantimonate, SbCl5, and by Ph3C+ AsF6-, were studied by H-1 and C-13 one- and two-dimensional nuclear magnetic reso nance using the COSY, S-INEPT, COLOC, and ROESY methods. If prepared i n the more solvating mixture of 1,1,2,2-tetrachloroethane (TCE) with 1 ,2-dichlorobenzene, the oligomers were found to be linear with the acy lium ion as a living group on one end; in TCE only, the oligomers are highly branched. In both cases, the propagation center appears to be s trongly coordinated to the nearest benzoylamide chain group. (C) 1993 John Wiley & Sons, Inc.