Using a New Pt(II) Source to Make Pt(II) Lantern-Shaped Cages, Including Low-Symmetry, Heteroleptic, and Multicavity Examples

Abstract

Current synthetic methods towards Pt(II) lantern-shaped cages involve the use of dry solvent, inert atmosphere, lengthy reaction times, and highly variable yields if isolated. Starting materials such as [Pt(CH3CN)4](BF4)2 suffer from a poor shelf-life, reducing the synthetic accessibility of various Pt(II) architectures. A new Pt(II) source (with varied counterions), [Pt(3-ClPy)4](X)2 (3-ClPy = 3-chloropyridine, X = BF4-, OTf-, NO3-), is developed and characterised, showing greatly enhanced shelf-life characteristics under ambient atmospheric conditions. Using this starting material, the assembly of Pt(II) lantern-shaped cages was completed in as little as 1.5 hours with wet solvent and ambient atmosphere. The first examples of low-symmetry, heteroleptic and multicavity Pt(II) lantern-shaped cages are reported using this approach. Attempts towards an M6L8 octahedron using a tritopic ligand instead generate an interesting M2L4 cage with unbound pyridyl arms. Ligands and cages are characterised by NMR spectroscopy, IR spectroscopy, mass spectrometry, and X-ray crystallography in some cases.