A serendipitous self-assembly synthesis of CNN–Pt pincer complexes

Abstract

In this work, we describe a serendipitous self-assembly synthesis of non-symmetrical CNN–platinacycle pincer complexes, with an early formation and detection of hydride species. The synthesis involves a formal C–H bond activation, with an earlier C–N bond formation via C–Br bond excision, instead of the expected rollover cyclometalated complex. According to our experimental results, the nature of the Pt(II)-starting material, having cyclooctene (COE), tetrahydrothiophene (THT) or Cl as co-ligands, does not affect the reaction pathway, and the best yields are achieved using stochiometric amounts of K₂PtCl₄, and the appropriate Schiff base ligand and aniline, at 70 °C for three days. Structures of platinacycle complexes have been supported by UV/Vis, IR, NMR and ESI-MS experiments, although specific ions formed in the ionization source were affected by the solvent used for compound solubilization/dilution.