Triazolate-based pillarplexes: shape-adaptive metallocavitands via rim modification of macrocyclic ligands

Abstract

Triazolate-based pillarplexes, supramolecular organometallic complexes (SOCs) featuring a tubular pore, are introduced. Following a macrocycle-templated synthesis strategy, a hybrid imidazolium/triazole cyclophane of defined ring size was used as ligand precursor, serving also as a supramolecular element in the subsequent SOC self-assembly. The new pillarplexes in part behave similar to previously reported pyrazolate-based congeners, e.g., regarding luminescence or host–guest properties. In contrast, for the Au(I) complex, an unprecedented shape-adaptive behaviour is observed in the solid-state, caused by the additional nitrogen atoms being present in the rim and rationalised by DFT calculations. Additionally, complementary hydrogen bonding between the cationic complexes is observed, proving that the rim modification not only modulates the flexibility of the cavitand but is also a tool to introduce further functionality into the SOC.