Self-Assembly of a Charge-Neutral Molecular Square

Abstract

Complexation of cadmium(II) by the ditopic (bis-tridentate) thiocarbazone ligand 1,5-bis(6-methyl-2-pyridyl- methylene)thiocarbonohydrazide, H₂L¹, results in the self-assembly of a charge-neutral 2 × 2 molecular grid, [Cd₄(L¹)₄], comprising four metals and four ligands in an interlocked cyclic array. The solid-state structure of this tetramer has been established by X-ray crystallography and in solution by ¹H NMR spectroscopy. The presence of lower molecular weight oligomers was identified by both NMR and ESI-MS.