Design, synthesis, and crystallographic studies of neutral platinum-based macrocycles formed via self-assembly

A series of neutral, platinum-based macrocycles was synthesized from rigid oxygen donor building blocks via self-assembly. The combination of a platinum-based 60degrees acceptor unit 1 with several linear and angular dicarboxylate bridging ligands afforded hitherto unknown neutral platinum-based supramolecular triangles and rhomboids. In addition, a similar reaction of the diplatinum molecular clip 6 and three different linear dicarboxylates led to the formation of neutral molecular rectangles. Most of the macrocycles were characterized by X-ray single-crystal structure analysis, and, in all cases, NMR spectra were consistent with the formation of single highly symmetrical species.