Metal-ion-induced shape switching: Stereoselective formation of a dinuclear Hg(II) double helicate from a hydrazonobis(acylhydrazone) ligand

The unsymmetrical hydrazonobis(acylhydrazone) ligand L exists in solution as a mixture of isomers but complexes to Hg(II) with a major conformational change, affording a mixture of parallel and antiparallel binuclear double helicates. On crystallisation of the triflate salt, however, the antiparallel strand isomer is selected presumably due to the optimisation of several weak interactions.

Graphical abstractIn solution, the ligand L exists as a mixture of isomers but binds to Hg(II) to give a mixture of parallel- and antiparallel-strand double helicates which, when crystallised, provides a single isomer of the ligand bound in a single (antiparallel) form of the helicate.Figure optionsDownload full-size imageDownload as PowerPoint slide