Integrative self-sorting is a programming language for high level self-assembly

Starting from the basis of a simple 4-component self-sorting system of crown ethers and ammonium ions, we design 6 building blocks in which 2 identical or different binding sites are incorporated. These building blocks can be mixed in many different ways to yield quite distinctly different pseudorotaxane assemblies. The self-sorting process integrates all building blocks in specific places so that this approach permits us to exert positional control and can widely influence the resulting assemblies with respect to the details of their structures. At maximum, we report quadruply interlocked species with up to 5 subunits that form specific assemblies. Although NMR methods are limited to the analysis of simpler complexes, ESI-MS and, in particular, tandem mass spectrometry is highly useful to analyze the assemblies' connectivities.