Lay summary
Lead:In our research we use calix[4]pyrroles as starting materials which are spontaneously formed by a simple chemical process known for more than 120 years. Calix[4]pyrroles are obtained without the need of external instruction. These classes of synthetic transformations have a flavor of spontaneous creation, a phenomenon, which is of general interest. These macrocycles are obtained by a simple process which is very similar to the biosynthetisis of the "pigments of life". They have attracted the attention of scientists interested in biosynthesis, prebiotic synthesis and natural products.Review:In contrast to the natural "pigments of life, the synthetic calix[4]pyrroles do not easily form transition metal complexes. Our group has proposed and developed a strategy, whereby the structurally blocked calix[4]pyrrole pyrroles can be transformed into efficient macrocyclic ligands. The reduction process studied in our group allows to obtain close relatives to the porphyrin-like "pigments of life". The four nitrogen ligands are in geometric positions close to the ones made available by the tetrapyrrolic cofactors. Different diastereomers of our novel ligand syntheticaly feasible and the influence of the relative configuration of the ligand on the metal complexation can be studied. Goal:The goal of our research is to make these novel and unique ligands available by studying new approaches to these ligand, by optimizing the reduction process used so far and by studying the properties of the ligands and their metal complexes.Significance:Our studies enlarge the structural variety of macrocyclices available to the chemists but also to other scientists. Metal complexes of macrocyclic ligands are good candidates for studies in catalysis, in material science, but also as sensors for studies of natural processes. The simplicity of the access studied in our group should make many different ligands available.