Coordination polymers from kinetically labile copper(I) and silver(I) complexes: true macromolecules or solution aggregates?

Abstract

Copper(I) and silver(I) coordination polymers have been prepared via conversion of equimolar amounts of o-phenanthroline-based bis-bidentate ligand monomers, and [Cu(CH3CN)4]PF6 or AgBF4 as the respective metal comonomers. Using NMR spectroscopy, the homogeneous constitution of the diamagnetic products has been proved, and their average chain length has been estimated to be Pn ≥ 20. Moreover, NMR studies showed the multinuclear complexes to be open (dynamic) solution aggregates when dissolved in solvents that contain coordinating species like acetonitrile or pyridine. When strictly non-coordinating solvents are used, on the other hand, the multinuclear complexes were found to be “true” polymers, i.e. macromolecules with a constant number of repeating units per individual chain in time. At very high dilution, finally, transformation of the originally formed chain molecules into cyclic oligomers was observed when coordinating solvents are used, but not in the case of non-coordinating solvents.