Polymer and Materials
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Readily soluble poly(2,9-o-phenanthroline-alt-(2′,5′-dihexyl)-4,4″-p-terphenylene) precursor polymers have been prepared via the Pd-catalyzed polycondensation reaction of 2,9-bis(p-bromophenyl)-o-phenanthroline and 2,5-dihexylbenzene-1,4-diboronic acid. Cyclotrimerization has been found to be the most important side reaction of this process which considerably lowers the yield of the precursor polymer when the coupling reaction is carried out at high dilution. However, cyclic oligomers would be separated off completely from the polymeric products by extraction with acetone. Subsequently, the constitutional homogeneity, the degrees of polycondensation, and the solution properties of the obtained polymers were analyzed using high-resolution NMR spectroscopy, osmometry, size-exclusion chromatography, viscosimetry and static light scattering. Finally, diamagnetic transition-metal complex polymers of well-defined constitution have been prepared by treating the precursor polymers with copper(I) and silver(I) compounds. Branching or crosslinking via the formation of intermolecular [M(phen)2] complexes could be suppressed in this final conversion by the addition of an appropriate amount of an “auxiliary ligand” L or L2 to the reaction mixtures: these latter ligands have been shown to reliably saturate the two remaining coordination sites of every transition-metal center of the complex polymers which are not occupied by the o-phenanthroline nitrogen atoms of the polymer main chains.
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