The
dinuclear anionic complexes [NBu<sub>4</sub>][(R<sub>F</sub>)<sub>2</sub>M<sup>II</sup>(μ-PPh<sub>2</sub>)<sub>2</sub>M′<sup>II</sup>(N<sup>∧</sup>O)] (R<sub>F</sub> = C<sub>6</sub>F<sub>5</sub>. N<sup>∧</sup>O = 8-hydroxyquinolinate, hq; M = M′
= Pt <b>1</b>; Pd <b>2</b>; M = Pt, M′ = Pd, <b>3</b>. N<sup>∧</sup>O = <i>o</i>-picolinate,
pic; M = Pt, M′ = Pt, <b>4</b>; Pd, <b>5</b>) are
synthesized from the tetranuclear [NBu<sub>4</sub>]<sub>2</sub>[{(R<sub>F</sub>)<sub>2</sub>Pt(μ-PPh<sub>2</sub>)<sub>2</sub>M(μ-Cl)}<sub>2</sub>] by the elimination of the bridging Cl as AgCl in acetone,
and coordination of the corresponding <i>N</i>,<i>O</i>-donor ligand (<b>1</b>, <b>4</b>, and <b>5</b>) or connecting the fragments “<i>cis</i>-[(R<sub>F</sub>)<sub>2</sub>M(μ-PPh<sub>2</sub>)<sub>2</sub>]<sup>2–</sup>” and “M′(N<sup>∧</sup>O)” (<b>2</b> and <b>3</b>). The electrochemical oxidation of the
anionic complexes <b>1</b>–<b>5</b> occurring under
HRMS(+) conditions gave the cations [(R<sub>F</sub>)<sub>2</sub>M(μ-PPh<sub>2</sub>)<sub>2</sub>M′(N<sup>∧</sup>O)]<sup>+</sup>, presumably endowed with a M(III),M′(III) core. The oxidative
addition of I<sub>2</sub> to the 8-hydroxyquinolinate complexes <b>1</b>–<b>3</b> triggers a reductive coupling between
a PPh<sub>2</sub> bridging ligand and the <i>N</i>,<i>O</i>-donor chelate ligand with formation of a P–O bond
and ends up in complexes of platinum(II) or palladium(II) of formula
[(R<sub>F</sub>)<sub>2</sub>M<sup>II</sup>(μ-I)(μ-PPh<sub>2</sub>)M′<sup>II</sup>(<i>P</i>,<i>N</i>-PPh<sub>2</sub>hq)], M = M′ = Pt <b>7</b>, Pd <b>8</b>; M = Pt, M′ = Pd, <b>9</b>. Complexes <b>7</b>–<b>9</b> show a new Ph<sub>2</sub>P-OC<sub>9</sub>H<sub>6</sub>N (Ph<sub>2</sub>P-hq) ligand bonded to the metal
center in a <i>P</i>,<i>N</i>-chelate mode. Analogously,
the addition of I<sub>2</sub> to solutions of the <i>o</i>-picolinate complexes <b>4</b> and <b>5</b> causes the
reductive coupling between a PPh<sub>2</sub> bridging ligand and the
starting <i>N</i>,<i>O</i>-donor chelate ligand
with formation of a P–O bond, forming Ph<sub>2</sub>P-OC<sub>6</sub>H<sub>4</sub>NO (Ph<sub>2</sub>P-pic). In these cases, the
isolated derivatives [NBu<sub>4</sub>][(Ph<sub>2</sub>P-pic)(R<sub>F</sub>)Pt<sup>II</sup>(μ-I)(μ-PPh<sub>2</sub>)M<sup>II</sup>(R<sub>F</sub>)I] (M = Pt <b>10</b>, Pd <b>11</b>) are anionic, as a consequence of the coordination of the resulting
new phosphane ligand (Ph<sub>2</sub>P-pic) as monodentate <i>P</i>-donor, and a terminal iodo group to the M atom. The oxidative
addition of I<sub>2</sub> to [NBu<sub>4</sub>][(R<sub>F</sub>)<sub>2</sub>Pt<sup>II</sup>(μ-PPh<sub>2</sub>)<sub>2</sub>Pt<sup>II</sup>(acac)] (<b>6</b>) (acac = acetylacetonate) also results
in a reductive coupling between the diphenylphosphanido and the acetylacetonate
ligand with formation of a P–O bond and synthesis of the complex
[NBu<sub>4</sub>][(R<sub>F</sub>)<sub>2</sub>Pt<sup>II</sup>(μ-I)(μ-PPh<sub>2</sub>)Pt<sup>II</sup>(Ph<sub>2</sub>P-acac)I] (<b>12</b>).
The transformations of the starting complexes into the products containing
the P–O ligands passes through mixed valence M(II),M′(IV)
intermediates which were detected, for M = M′ = Pt, by spectroscopic
and spectrometric measurements
