Synthesis and reactivity of a platinum(II) complex with a chelating dehydro(arylboronic anhydride) ligand. Transmetalation of arylboronic acid

The reaction of ArB(OH)(2) (Ar = C6H4OMe-4, Ph, C6H4COMe-4) with PtI2(dppe) in THF in the presence of Ag2O and H2O at room temperature produced a Pt complex with a chelating dehydro(arylboronic anhydride) ligand, Pt(OBArOBArO)(dppe) (1a, Ar = C6H4OMe-4; 1b, Ar = Ph; 1c, Ar = C6H4COMe-4). The complexes were characterized by NMR spectroscopy and X-ray crystallography. Reactions of protonic acids, such as HCl, CF3COOH, and CH3COOH, with 1a yielded complexes with chloro and carboxylate ligands, PtX2(dppe) (2, X = Cl; 3, X = OCOCF3; 4, X = OCOMe). The complexes 1a-c react with arylboronic acids bearing the same aryl group as the ligands of the complexes to form diarylplatinum complexes, PtAr2(dppe) (5a, Ar = C6H4OMe-4; 5b, Ar = Ph; 5c, Ar = C6H4COMe-4), respectively. Reactions of 4-MeCOC6H4B(OH)(2) with 1b and of PhB(OH)(2) with 1c in 2:1 molar ratios form mixtures of three diarylplatinum complexes in a statistical ratio.