Construction of organometallic trefoil knots and one-dimensional chains featuring half-sandwich Cp*Rh corner units and an abnormal zwitterion ligand

Abstract

An abnormal O-coordinated zwitterionic ligand L was designed and applied to construct intricate supramolecular elements based on half-sandwich Cp*Rh units. This zwitterionic ligand has two stable conformations, C- and Z-shapes, which undergo self-adaptation when assembled with different building blocks. Two trefoil knots were obtained using dinuclear building blocks (Cp*Rh)₂(1,4-DHATQ)(OTf)₂ and (Cp*Rh)₂(DHNAD)(OTf)₂, in which the ligand L was observed to adopt its C-shaped conformation. In addition, two novel one-dimensional chains were constructed using the building blocks (Cp*Rh)₂(1,5-DHATQ)(OTf)₂ and (Cp*Rh)₂(DHNTQ)(OTf)₂. Only the Z-shaped conformation of ligand L was observed in these two 1D chains.