Functional heteroleptic coordination cages based on a modular approach

Abstract

This work describes the rational design of a family of endohedrally functionalized heteroleptic coordination cages of the type Pd2A2B2. These were assembled out of a modular toolbox of banana shaped ligands A based on carbazole and shape complementary ligands B with different aromatic backbones and lengths. The obtained structures were characterized by NMR spectroscopy and ESI mass spectrometry as well as for some examples with X-ray diffraction in the solid state. With installing different functional groups to the free secondary amine at the carbazole moiety, namely amides and methyl substituents a variety of coordination cages with unique properties inside the cavities were formed. The coordination cages were investigated in their ability to bind hydrogen bond acceptors. Another goal of this work was the NMR spectroscopic investigation of coordination assemblies. With the help of tailor-made NMR experiments new cage compounds were characterized. The main focus was laid on DOSY NMR experiments.