Multivalent N-donor ligands for the construction of coordination polymers and coordination polymer gels

Abstract

This work describes the synthesis and characterisation of several multivalent N-donor ligands and their coordination compounds and the use of these ligands in the construction of coordination polymers and coordination polymer gels. The project can be divided into two parts. The first part of the research is focused on the coordination chemistry of ring-substituted biimidazoles in acidic media. The dependence of the formation of ion pairs and zwitterionic, especially zinc and copper containing coordination compounds on the pH of the reaction medium and ring-substituents of the ligand were examined. The second part of the study deals with the preparation of Ag, Zn and Cu coordination polymers (CPs) and coordination polymer gels (CPGs) from geometrically flexible biimidazole- and bipyridine-based ligands. The effect of metal centres and reaction conditions on structural topologies of CPs was studied and presented in publication II. Since the CPGs were obtained by silver coordination, a new photochemical process was developed to form silver nanoparticles (AgNP) on the surface of the coordination polymeric fibers. The method was disclosed in publications III and IV. In order to explain and combine these different studies into one thesis, the following procedure was followed: first, an introduction to the N-donor ligands, especially biimidazole and bipyridines and their coordination chemistry in acidic and basic media was presented. The later part was focused on general synthetic routes for CPs and possibilities to control their structure with literature examples. The chapter then gives an introduction to the gels, and supramolecular metallogels with examples of recent publications and gel characterisation methods. The introduction ends with the aim of the study. The second part of the thesis outlines the most significant findings reported in the four original publications. The discussion part begins with a short chapter on the synthesis of a series of N-donor ligands, followed by their coordination chemistry in an acidic medium. The follow-up chapter deals with the construction of CPs and CPGs with semirigid ligands. The final chapter of the discussion ends with the luminescence properties of these CPs and CPGs. At the end of the thesis, these results are briefly summarised with significant findings.