Intramolecular C–H activation by air-stable Pt(II) phosphite complexes
Air-stable L2PtMe2 complexes ligated by bulky aryl phosphite ligands were synthesized and characterized. The aryl phosphite ligands were prepared from substituted phenols and PCl3 or P(NMe2)3 without the use of an external base. The steric environment of the phenol controlled the number of substitutions at P(NMe2)3, resulting in selective formation of P(NMe2)(O-2,6-Me2C6H3)2. The phosphite ligands and their corresponding platinum(II) complexes were found to be air stable and robust. X-ray diffraction structures of the platinum(II) complexes were obtained in order to determine the steric environment around the metal centers. Thermolysis of the L2PtMe2 complexes in C6D6 at 100 °C results in loss of methane and formation of one major platinum-containing product in high yield. The products of thermolysis were found to be a result of cyclometalation by C–H activation of a sp3 C–H bond in the ligand to form a 6-membered ring, as confirmed by X-ray crystallography.
Journal of Organometallic Chemistry Volumes 799–800, 15 December 2015, Pages 201-207