Catenands Built on Poly(ethylenimine). Attachment of Two Phenanthrolines in Close Proximity on the Polymer Backbone

In an attempt to establish a methodology for introduction of two or more functional groups in close proximity to the backbone of synthetic polymers, two molecules of a 1,10-phenanthroline were preassembled with Cu(I) ion and then cross-linked with poly(ethylenimine) (PEI) to obtain [Cu(I)Phen2]PAPEI. Removal of Cu(I) ion from [Cu(I)Phen2]PAPEI produced [apoPhen2]PAPEI, whose primary and secondary amines were subsequently acetylated to produce [apoPhen2]PAAcPEI. Cross-linkage of each preassembled phenanthroline pair with PEI through four-point attachment would produce two interlocking macrocycles linked to each other or two fused entwining macrocycles. The former is a special class of catenand, whereas the latter is a catenand analogue. Ionization constants for the phenanthroline moieties and formation constants for the Cu(II) complex were measured for the PEI derivatives. The results indicate that the geometry of two phenanthrolines originally assembled by Cu(I) ion is effectively conserved in [apoPhen2]P...