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C,N-cyclopalladated complexes are among the most robust and widely used (pre)catalysts of cross-coupling reactions, combining long shelf life with high catalytic activity. In this report, we describe synthesis and properties of new Pd(II) complexes of a flexidentate ligand – 2,2-dimethyl-5-(2-pyridyl)pentane-3,5-dione (HL). Its coordinating properties resulted in the formation of two stereoisomeric cis- and trans-PdL2 complexes each with one ligand in O,O- and the other in N,C(sp3)-coordination modes. The solid-state structures have been established by means of single-crystal X-ray diffraction methods and are retained in solution as indicated by NMR spectroscopy. Both these isomers proved to be efficient (pre)catalysts of phosphine-free Heck cross-coupling of iodoarenes with olefins.

The reaction between ionic liquid [Cat]+Cl− (where Cat stands for 1-butyl-3-methylimidazolium, 1-butyl-2,3-dimethylimidazolium or 1-butyl-4-methylpyridinium) and the metal precursor ([PtCl2(cod)], PtCl4, K2[PtCl4] or K2[PtCl6]) yielded two groups of derivatives: [Cat]+[PtCl4]− and [Cat]+[PtCl6]−, which formally are counted among halometallate ionic liquids, however, due to their high melting points they should be classified into anionic platinum complexes rather than into ionic liquids. All the derivatives were isolated and characterized spectroscopically (NMR, ESI-MS) and crystallographic structures were determined for three derivatives: ([BMPy]2[PtCl4], [BMIM]2[PtCl6] and [BMMIM]2[PtCl6]. Moreover, their melting points were measured and thermal stability was assessed. The above derivatives were employed as catalysts for hydrosilylation of olefins with diverse properties. All the studied catalysts showed high activity and their insolubility in the reaction medium made easy their isolation and multiple use in subsequent catalytic runs. The most effective catalysts did not lose their activity even after ten runs, thereby they make a very good alternative to commonly used homogeneous catalysts. Their simple synthesis and stability make them interesting both for economic and ecological reasons.

Two new air- and water-stable Pt(II) metallosupramolecular complexes based on ambidentate ligands have been designed, synthesized and fully characterized. The structure of complexes has been determined by various analytical techniques including NMR spectroscopy and TOF-MS. Additionally, the single crystal structure of 2 was determined by X-ray diffraction. The catalytic activity of these complexes in hydrosilylation has been investigated, establishing that both have similar high activity and selectivity within a broad scope of structurally distinct olefins and hydrosilanes.