Ks. Alva et al., ENZYME-CATALYZED POLYMERIZATION OF 8-HYDROXYQUINOLINE-5-SULFONATE BY IN-SITU NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY, Journal of applied polymer science, 70(7), 1998, pp. 1257-1264
In this report, we describe the use of in situ NMR spectroscopy to elu
cidate the mechanism of horseradish peroxidase-catalyzed oxidative fre
e-radical coupling of phenols. We demonstrate the potential of the tec
hnique for the polymerization of 8-hydroxyquinoline-5-sulfonate (HQS).
Based on the structural changes, we establish the involvement of orth
o- and para-position protons (to the hydroxyl group) in the oxidative
free-radical coupling polymerization with their relative preferences.
For example, in HQS, we establish that the positions 2, 4, and 7 are i
nvolved in the chemical bonding with the order of preference being 7 g
reater than or equal to 2 > 4. Analyses of C-13-NMR data suggest the f
ormation of C-C- and C-O-C-type coupling bonds during enzymatic polyme
rization. (C) 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1257-1
264, 1998.