Photopolymerization of Poly (Ethylene Glycol) Diacrylate/Cation Complexes: Synthesis of Pseudocrown Ethers

Polymenc pseudocrown ether networks were formed in situ by the photopolymerization of poly(ethylene glycol) diacrylate (PEGDA) / transition metal complexes. These metal : monomer complexes led to near circular conformations of the monomers in which the two reactive endgroups of a single monomer are brought into close proximity; thus, the probability of intramolecular cyclization (i.e. pseudocrown ether formation) is increased. Complexes of cobalt(ll) and nickel(ll) were characterized using FTIR and Uv-vis spectroscopy. A novel technique of replacing coordinated water molecules by monomeric ether oxygens was discovered. Photopolymenzations of templated PEG200DA exhibited a decrease in autoacceleration
as an indication of pseudocrown ether formation due to the reduction in the degree of crosslinking with cyclization. Both 0, and o6H20 were found to make suitable templating ions.
Facilitated transport membranes using pseudocrown ethers were selective for alkali metals over
transition and lanthanide metals. The K(l) over Na(l) selectivity was 1 .53, while the selectivity of K(l) over Nd(lll) was as high as 3,700.