Coordination polymer networks: an alternative to classical polymers ?

This chapter of "Polymer Networks: Synthesis, Properties, Theory and Applications" provides a brief overview on metal ion containing coordination polymer networks, how and why they are made, as an alternative to classical polymers. Our focus will be polymorphism, supramolecular isomerism and pseudo-polymorphism. Examples from our group of metal ion containing coordination polymer networks with flexible molecules as building blocks will be highlighted, as they might show parallels with purely organic polymer compounds

Silver coordination polymers with isonicotinic acid derived short polyethylene glycol – Synthesis, structures, anion effect and solution behavior

Silver coordination compounds and one-dimensional polymers have been studied, using a linear, flexible N-donor ligand. The solid state structures are well known and show panoply of different structures including a large number of polymorphism, pseudo-polymorphism and isomers. We have studied these structures under the influence of anions, solvents and crystallization conditions, studying also some solution effects. We here present an overview with highlights of some case studies of the synthesis, structures, anion and solvent effects as well as solution behavior during formation of silver coordination polymers. Finally, we will give an outlook on the potential applications of these materials

On the coordination behaviour of NO₃⁻ in coordination compounds with Ag⁺Part 1. Solubility effect on the formation of coordination polymer networks between AgNO₃ and <strong>L</strong>(<strong>L</strong>= ethanediyl bis(isonicotinate) as a function of solvent

The influence of the solubility of AgNO₃ in three solvent systems is studied for the reaction between AgNO₃ and the ligand L(= ethanediyl bis(isonicotinate)). Three solid state structures are obtained, differing in the relative ratio Ag : L in the first case, and in polymorphism in the second. The Ag–O(NO₃⁻) distance correlates strongly with the solubility of AgNO₃ in the used solvent. Solution studies prove indeed the existence of close ion contact pairs in the less good solvents, where as ion solvation is observed in good solvents for AgNO₃. The three different structures are compared to two solvated structures in which H₂O demonstrates coordination to the nitrate anion via H-bonding

The first two-dimensional polycatenane: a new type of robust network obtained by Ag-connected one-dimensional polycatenanes

The two-dimensional structure described here is the first example of a coordination polymer structure consisting of one-dimensional polycatenanes fused via silver ions. It can be derived from simple rings consisting of two silver ions and two ligand molecules

Rings, chains and helices: new antimicrobial silver coordination compounds with (iso-)nicotinic acid derivatives

Complexes with silver ions have great potential for applications in medicine. Appropriate bidentate ligands, binding to silver ions, are able to generate coordination polymers as well as molecular entities as a function of ligand flexibility, conformation and length. Here we present the continuation of our previous studies in this field with ligands based on oligomers of polyethylene glycol, functionalized at both ends with either nicotinic or isonicotinic acid. The structures of three ligands and nine new coordination compounds are presented. A large variety of structures are obtained as a function of counterion, solvent and ligand-to-metal ratio, such as isolated rings, offset stacked rings, parallel chains and entangled chains, and their antimicrobial properties as well as biocompatibility are assessed

Of chains and rings: synthetic strategies and theoretical investigations for tuning the structure of silver coordination compounds and their applications

Varying the polyethyleneglycol spacer between two (iso)-nicotinic groups of the ligand systems, a large structural variety of silver coordination compounds was obtained, starting with zero-dimensional ring systems, via one-dimensional chains, helices and double-helices to two-dimensional polycatenanes. Theoretical calculations help to understand their formation and allow predictions in some cases. These structures can be tuned by careful design of the ligand, the use of solvent and the counter ions, influencing also other important properties such as light stability and solubility. The latter is important in the context of biomedical applications, using silver compounds as antimicrobial agents