Synthesis and alkali cation binding properties of photodimerizable polymers with differently sized crown ethers

Abstract

Polymers, with differently sized crown ethers as alkali cation binding sites and photodimerizable cinnamoyl moieties in their side-chains, were prepared by the cationic copolymerization of the corresponding monomers. The form of the crown-cation complexes (1:1 or 2:1) was studied by measuring quantum yields for the photodimerization of the crown-connected cinnamoyl units in the presence of alkali metal chlorides and by measuring the shift of λ max of alkali metal picrates in THF on addition of the crown polymers. The alkali metal cation binding ability and selectivity of the photodimerizable polymers with different crown ethers (studied by a method of picrate salts extraction) were compared with those of blended samples of the photodimerizable polymers with one kind of crown ether unit. On irradiation with u.v. light, the crown-connected cinnamoyl moieties of the polymers dimerized even in dilute solutions. Studies were made of the effects on the alkali cation binding ability and selectivity of: the photo- The effects on the alkali cation binding ability and selectivity of: the photodimerization of the cinnamoyl moieties of the polymers; the degree of photodimerization of the polymers; and the kind of alkali cations used as templates during the photodimerization of the polymers; were studied.