OXAAZA MACROCYCLES CONSTRUCTED ON POLY(ETHYLENIMINE) THROUGH NI(II)-TEMPLATE CYCLIZATION AND THEIR METAL-BINDING

Polymeric oxaaza macrocycles (PEI-OAM) are constructed on poly(ethylen imine) (PEI) by Ni(II)-template alkylation of PEI with diethyleneglyco l ditosylate. The Kf values for Ni(II), Cu(II), and Zn(II) complexes o f PEI-OAM are measured at pH 3.5-10 at 25 degrees C. At pH 7, log K-f values for these complexes are 9-15, indicating that the polymeric oxa aza macrocycles can readily reduce concentrations of these metal ions below ppb level. Metal binding ability of nonpolymeric oxaaza macrocyc lic compounds reported in the Literature decreases rapidly as pH is lo wered below 7, whereas that of PEI-OAM decreases to lesser extents. Th is is attributed to the electrostatic effects exerted by the ammonium ions of PEI backbone. (C) 1997 John Wiley & Sons, Inc.