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

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.