Solid state C-13 nuclear magnetic resonance for polyguanidines

The structure and variations in dynamic motions of three polyguanidines pos sessing different side chains were studied by C-13 CP/MAS NMR. From these r esults, the structures of the polyguanidines were confirmed, and the C-13 s pin-lattice relaxation times in the rotating frame were measured. The polyg uanidine backbone mobilities were measured as a function of size and chemic al make up (aliphatic vs. aromatic). The main-chain carbon of polyguanidine (II) with aromatic side chains has a higher activation energy, 23.12 KJ/mo l, than the polyguanidine (1) with aliphatic side chains, 19.76 KJ/mol. Als o, the activation energy of the main-chain carbons of polyguanidine (II) an d (LII) with aromatic side chains was found to depend on the size of side c hains. (C) 1999 Elsevier Science Ltd. All rights reserved.