Synthesis and Reactivity of a Platinum(II) Complex with a Chelating Dehydro(arylboronic anhydride) Ligand. Transmetalation of Arylboronic Acid

2006-03-27T00:00:00Z (GMT) by Ivayla Pantcheva Kohtaro Osakada
The reaction of ArB(OH)<sub>2</sub> (Ar = C<sub>6</sub>H<sub>4</sub>OMe-4, Ph, C<sub>6</sub>H<sub>4</sub>COMe-4) with PtI<sub>2</sub>(dppe) in THF in the presence of Ag<sub>2</sub>O and H<sub>2</sub>O at room temperature produced a Pt complex with a chelating dehydro(arylboronic anhydride) ligand, (<b>1a</b>, Ar = C<sub>6</sub>H<sub>4</sub>OMe-4; <b>1b</b>, Ar = Ph; <b>1c</b>, Ar = C<sub>6</sub>H<sub>4</sub>COMe-4). The complexes were characterized by NMR spectroscopy and X-ray crystallography. Reactions of protonic acids, such as HCl, CF<sub>3</sub>COOH, and CH<sub>3</sub>COOH, with <b>1a</b> yielded complexes with chloro and carboxylate ligands, PtX<sub>2</sub>(dppe) (<b>2</b>, X = Cl; <b>3</b>, X = OCOCF<sub>3</sub>; <b>4</b>, X = OCOMe). The complexes <b>1a</b>−<b>c</b> react with arylboronic acids bearing the same aryl group as the ligands of the complexes to form diarylplatinum complexes, PtAr<sub>2</sub>(dppe) (<b>5a</b>, Ar = C<sub>6</sub>H<sub>4</sub>OMe-4; <b>5b</b>, Ar = Ph; <b>5c</b>, Ar = C<sub>6</sub>H<sub>4</sub>COMe-4), respectively. Reactions of 4-MeCOC<sub>6</sub>H<sub>4</sub>B(OH)<sub>2</sub> with <b>1b</b> and of PhB(OH)<sub>2</sub> with <b>1c</b> in 2:1 molar ratios form mixtures of three diarylplatinum complexes in a statistical ratio.