Synthesis of Bis(2,6-dinitroaryl)palladium(II) and Mono(2,6-dinitroaryl)platinum(II) Complexes. A New Example of the Transphobia Effect and of Transmetalation from Pt to Hg

The reaction of [Pd(κ<sup>2</sup>-Ar)(O,O-acac)] (κ<sup>2</sup>-Ar = κ<sup>2</sup>-<i>C,O</i>-C<sub>6</sub>(NO<sub>2</sub>)<sub>2</sub>-2,6-(OMe); <b>1</b>) with 1 equiv of RNC gives [Pd(κ<sup>2</sup>-Ar)(O,O-acac)(CNR)] [R = Xy (<b>2a</b>), <sup><i>t</i></sup>Bu (<b>2b</b>)] and with 4 equiv of XyNC, <i>trans</i>-[Pd(κ<sup>1</sup>-Ar)<sub>2</sub>(CNXy)<sub>2</sub>] (κ<sup>1</sup>-Ar = κ<sup>1</sup>-<i>C</i>-C<sub>6</sub>(NO<sub>2</sub>)<sub>2</sub>-2,6-(OMe); <b>3</b>). This complex has also been obtained (1) by reacting Tl(acac) with 1 equiv of <i>trans</i>-[Pd(κ<sup>1</sup>-Ar)Cl(CNXy)<sub>2</sub>] (<b>4</b>), obtained in turn by reacting <i>trans</i>-(NMe<sub>4</sub>)<sub>2</sub>[Pd(κ<sup>1</sup>-Ar)Cl(µ-Cl)]<sub>2</sub> (<b>5</b>) with 4 equiv of XyNC or (2) by reacting [Pd(κ<sup>1</sup>-Ar)(<i>C</i>-acac)(phen)] (<b>6</b>) with 4 equiv of XyNC. <i>cis</i>-[Pt(κ<sup>2</sup>-Ar)(κ<sup>1</sup>-Ar)(PPh<sub>3</sub>)] (<b>7</b>) reacts (1) with Hg(OAc)<sub>2</sub> (1:1) to afford a mixture of [Hg(Ar)(OAc)], <i>cis</i>-[{Pt(κ<sup>1</sup>-Ar)(PPh<sub>3</sub>)}<sub>2</sub>(µ-OH)(µ-OAc)] (<b>8</b>), and <i>trans</i>-[{Pt(κ<sup>1</sup>-Ar)(PPh<sub>3</sub>)}<sub>2</sub>(µ-OH)<sub>2</sub>] (<b>9</b>) or (2) with HgCl<sub>2</sub> (1:1) to give <i>trans</i>-[{Pt(κ<sup>1</sup>-Ar)(PPh<sub>3</sub>)}<sub>2</sub>(µ-Cl)<sub>2</sub>] (<b>10</b>), which reacts with an excess of Ag(OAc) to give <b>8</b>. The reaction of <b>10</b> with excess of KOH, or with Tl(acac) (1:1) gives <b>9</b>. Reaction of palladium complex <b>5</b> with 2 equiv of Hg(OAc)<sub>2</sub> affords <i>trans</i>-[Pd(κ<sup>2</sup>-Ar)(µ-OAc)]<sub>2</sub> (<b>11</b>). The crystal structures of <b>2a</b>, <b>2b</b>, <b>3</b>, <b>5</b>, <b>8</b>, <b>9</b>, and <b>11</b> have been determined.