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

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) 6 or AgBF 4 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.

Coils, Rods and Rings in Hydrogen‐Bonded Supramolecular Polymers

“…Today, the topic is rapidly gaining importance within the field of synthetic self-assembling systems, and includes coordination polymers, [101] hydrogen-bonded polymers, and columnar systems based on solvophobic interactions, [102] with topologies ranging from linear chains to highly crosslinked reversible networks. In this Feature Article, we have used a narrow selection of examples, mainly from our own work in this field, to illustrate some of the issues and opportunities that lie ahead.…”

Effect of Orientational Specificity of Complexation on the Behavior of Supramolecular Polymers: Theory and Simulation

“…While solution of the proposed equations is rather straightforward, to obtain so many equilibrium constants from experimental measurements is rather cumbersome, taking into account that even the determination of the molecular weight represents a challenge for such "living" polymers. 5,19 Another technical problem is that the ring-chain equilibrium constant for larger rings is often theoretically estimated based on Gaussian statistics, 7,11,16,17,20,21 although supramolecular polymers formed by self-assembly of a flexible spacers in a good solvent often behave more like chains with excluded volume than Gaussian chains. Associating monomers with excluded volume have been studied in considerable detail in computer simulations, 12,13,15,22,23 although in these cases orientational specificity either was not considered 22,23 or it was applied to all monomers (oligomer size one).…”

Supramolecular Branching and Crosslinking of Terpyridine‐Modified Copolymers: Complexation and Decomplexation Studies in Diluted Solution

“…[17] Linear coordinative polymers of bis-phenanthrolines with copper(I) or silver(I) form dynamic (small) aggregates in coordinating solvents, but stable macromolecules in noncoordinating solvents. [18] A powerful building block for reversible supramolecular polymers is 2,2 0 :6 0 ,2 00 -terpyridine, [19] which is capable of forming stable chelate complexes with a variety of transition metal ions. It can be easily introduced into polymers by copolymerization of a common monomer together with a terpyridine-modified monomer.…”