Chiral Self‐Sorting Effects in the Self‐Assembly of Metallosupramolecular Aggregates Comprising Ligands Derived from Tröger's Base

Abstract

Five ligands with either nitrile or isonitrile metal binding motifs have been synthesized based on the 2,8‐ or 3,9‐disubstituted Tröger's base scaffold, respectively. These ligands self‐assemble into dinuclear cyclic metallosupramolecular aggregates upon coordination to [(dppp)Pd(OTf)2] in a highly diastereoselective manner, by heterochiral self‐sorting in a chiral self‐discriminating manner as shown by ESI mass spectrometry, NMR spectroscopy, and single crystal XRD analysis. This observation is in contrast to earlier studies with ligands derived from Tröger's base that have larger metal binding motifs and bis(nitrile) and bis(isonitrile) ligands based on other rigid dissymmetric cores such as [2.2]paracyclophanes. Thus, the combination of these slim metal binding motifs with the rigid v‐shaped 2,8‐ or 3,9‐disubstituted Tröger's base scaffolds seems to be especially well preorganized to ensure high‐fidelity social self‐sorting behavior.

Cyclic Diplatinum Complex with a Tröger's Base Ligand and Reductive Elimination of a Highly Strained Ring Molecule

“…Previous studies on the NMR measurement revealed stereoselective sorting of two chiral molecules [17,25] . A transition metal complex with metallosupramoleular aggregate of a TB‐based ligand was reported [25e] . The NMR results of this work also indicate diastereoselective formation of 3 and of its precursor 1 .…”