New Route to Cycloplatinated N‐Heterocyclic Carbene Complexes via Iodide Assisted C‐H Activation and Proton Transfer

ABSTRACT A convenient strategy to access cyclometalated platinum (II) N‐heterocyclic carbene (NHC) complexes is reported herein, synthesized by treating a Pt (NHC)I 2 Py precursor with Schiff‐base (N^O) ligands in the presence of K 2 CO 3 base under mild reaction conditions. These cyclometalated Pt(II) NHC complexes were fully characterized by 1 H and 13 C NMR, mass spectrometry, and infrared spectroscopies, and the solid‐state molecular structures of complexes 1 , 2b , and 3b were unambiguously determined by single‐crystal X‐ray diffraction methods. To form these complexes, C‐H bond activation and C‐N cleavage and cycloplatination had to occur. In a bid to understand this transformation, density functional theory was carried out to rationalize the cycloplatination mechanism unveiling an intriguing anion assisted C‐H activation and proton transfer process.