Coordination polymers from kinetically labile transitionmetal complexes: True macromolecules or only dynamic solution aggregates?

Abstract

Abstract Readily soluble copper(I) and silver(I) coordination polymers have been prepared via the conversion of equimolar amounts of p -phenyleneethynylenebridged bis [9-( p -anisyl)- o -phenanthroline] ligand monomers and [Cu(CH 3 CN) 4 ]PF 6 or AgBF4 as their metal-monomer counterparts. The homogeneous constitution of the resulting diamagnetic macromolecules is proven using NMR spectroscopy. Their average degrees of polymerization have been shown to reach values of P n ≥ 20, and the intrinsic viscosity of the resulting randomly coiled polyelectrolytes is of the order [η] ≈ 30 mL/g in 0.01 M NH 4 PF 6 /acetone. Moreover, NMR and viscosity experiments show the chain molecules to be open solution aggregates when dissolved in coordinating solvents like acetonitrile or water. When dissolved in noncoordinating solvents, 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 with respect to time. At very high dilution, transformation of the high-molecular-weight chain molecules into cyclic oligomers is observed in coordinating solvents but not in non-coordinating media.