The reactions of the bis-NHC platinum complex cis-[PtMe2(bisNHC1)], 1, in which bisNHC1 = 1,1′-methylene-3,3′-bis[(N-(tert-butyl)imidazole-2-ylidene], with strong acids and thermolysis of the reaction products were investigated. The reaction of 1 with 1 equiv B(C6F5)3 in acetone gave the borate complex cis-PtMe(bisNHC1)[OHB(C6F5)3], 2, that undergoes CH bond activation of one of the tBu wingtips at 50 °C and yields the cyclometalated platinum complex Pt(bisNHC1′)[OHB(C6F5)3], 3, (where the prime denotes the cyclometalated ligand). However, the migration of two C6F5 groups from boron to the platinum center was observed when the thermolysis of 3 carried out in the presence of a large excess of benzene in acetone at 50 °C and gave the bis-NHC platinum complex cis-[Pt(C6F5)2(bisNHC1)], 4. The reaction of 1 with trifluoroacetic acid (TFAH) gave the bis-NHC platinum(II) complex cis-[Pt(bisNHC1) (TFA)2], 6, that is stable at 80 °C for several days. All complexes were characterized using NMR spectroscopy and the crystal structures of 4 and 6 were determined using X-ray crystallography.
Cyclometalation and pentafluorophenyl transfer in protonolysis of a chelating Bis-NHC Platinum(II) complex
J. Organomet. Chem. 2018, 876, 43-49, DOI: 10.1016/j.jorganchem.2018.08.023.