GLOBAL AND INTERNAL MOLECULAR-DYNAMICS OF POLY(ACRYLAMIDE-CO-ALLYL 2-ACETAMIDO-2-DEOXY-D-GLUCOPYRANOSIDE) GLYCOPOLYMERS FROM C-13 NMR RELAXATION STUDIES

C-13 spin-lattice and spin-spin relaxation times and nuclear Overhause r enhancements have been used to examine the molecular dynamics of the alpha- (1) and beta- (2) anomeric forms of poly(acrylamide-co-allyl 2 -acetamido-2-deoxy-D-glucopyranoside) glycopolymers. The timescale of motions and the spatial restriction of these motions were determined b y using various forms of the ''model-free'' approach. It is shown that the motions of the C-H vectors of the polymer backbone may be describ ed by a scaled Lorentzian spectral density function, giving rise to an effective correlation time for overall tumbling. The temperature depe ndence of this correlation time suggests that the overall motion is de pendent on viscosity. The overall motion of the polymer molecules is s hown to be anisotropic in nature by including the spin-spin relaxation data in the analysis. The N-acetyl methyl and sugar hydroxymethyl (C- 6) groups exhibit internal motions. The activation energies associated with these internal motions are derived. The difference in relaxation rates between the alpha and beta anomeric forms, though small, sugges ts that the motions of the sugar ring may be different for the two sys tems. This conclusion is supported by potential energy contour map cal culations, which indicate that the beta anomer (2) has almost twice th e conformational flexibility of the alpha anomer (1).