Threefold Symmetric Trimetallic Macrocycles Formed via the Weak-Link Approach

The synthesis and characterization of a new threefold symmetric hemilabile phosphino-alkylthioether ligand are described. This ligand can be used in combination with Rh(I) and Ir(I) precursor complexes to prepare 40-membered macrocyles with threefold symmetry via the Weak-Link Approach. Synthesis and characterization of two such structures are reported along with a single crystal x-ray diffraction analysis of one of the key intermediates in the case of Rh(I). This is a demonstration of the viability of the Weak-Link Approach for preparing structures other than bimetallic macrocycles and suggests that it could be generalized for a wide range of higher symmetry structures through appropriate hemilabile ligand design.