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“Total” analysis of the growing species in living cationic polymerizations by in‐situ multinucleate NMR spectroscopy
Author(s) -
Sawamoto Mitsuo
Publication year - 1994
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19940880109
Subject(s) - carbocation , cationic polymerization , chemistry , nuclear magnetic resonance spectroscopy , polymerization , in situ , spectroscopy , medicinal chemistry , stereochemistry , polymer chemistry , organic chemistry , physics , quantum mechanics , polymer
The nature of the growing species in living cationic polymerizations of vinyl ethers was discussed on the basis of in‐situ direct analysis of model growing ends [CH 3 C δ+ H(O i Bu)… B δ …MX n ] by multinuclear NMR spectroscopy. The model reactions were to mimic the polymerizations initiated with protonic acid/metal halide systems [HB/MX n ; HB = HCl, CF 3 CO 2 H, (C 6 H 5 O) 2 PO 2 H; MX n = ZnCl 2 , SnCl 4 ], where all of the three components of the growing end [carbocation (∼∼C+), counter‐anion (B − ), and activator (MX n )] were analyzed by monitoring such nuclei as 1 H, 13 C, 19 F, 31 P, and 119 Sn incorporated therein. The results demonstrated: (i) the MX n ‐assisted formation of sp 2‐type carbocations from the precursor CH 3 CH(O i Bu)‐B; (ii) the interaction of MX n with the counteranion B − ; and (iii) the suppression of dissociated carbocationic intermediates under the living polymerization conditions.