Coordination Studies of a New Nonsymmetric Ditertiary Phosphane Bearing a Single Phosphaadamantane Cage

<jats:title>Abstract</jats:title><jats:p>The new nonsymmetric ditertiary phosphane, Ph<jats:sub>2</jats:sub>P(CH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>PAd (<jats:bold>1</jats:bold>), was prepared in one‐step from Ph<jats:sub>2</jats:sub>PCH=CH<jats:sub>2</jats:sub> andH‐PAd (H‐PAd = 1,3,5,7‐tetramethyl‐2,4,8‐trioxa‐6‐phosphaadamantane) by a hydrophosphination reaction using 2,2′‐azo‐bisisobutyronitrile (AIBN) as free radical initiator. The sterically encumbered phosphaadamantane cage in <jats:bold>1</jats:bold> was found to influence the coordination capabilities of this ligand. The reaction of <jats:bold>1</jats:bold> with [PdCl<jats:sub>2</jats:sub>(cod)] or [Pt(CH<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>(cod)] (cod = cycloocta‐1,5‐diene) gave the corresponding κ<jats:sup>2</jats:sup>‐<jats:italic>P,P′</jats:italic>‐chelate complexes <jats:italic>cis</jats:italic>‐[PdCl<jats:sub>2</jats:sub>(<jats:bold>1</jats:bold>)] (<jats:bold>2</jats:bold>) and <jats:italic>cis</jats:italic>‐[Pt(CH<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>(<jats:bold>1</jats:bold>)] (<jats:bold>3</jats:bold>), respectively. The dinuclear gold(I) complex [Ph<jats:sub>2</jats:sub>P(AuCl)(CH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>PAd(AuCl)] (<jats:bold>4</jats:bold>) was prepared from <jats:bold>1</jats:bold> and 2 equiv. of [AuCl(tht)] (tht = tetrahydrothiophene). In contrast, the cleavage of the chloro‐bridged dimers {RuCl<jats:sub>2</jats:sub>(η<jats:sup>6</jats:sup>‐<jats:italic>p</jats:italic>‐cymene)}<jats:sub>2</jats:sub> or {MCl<jats:sub>2</jats:sub>(η<jats:sup>5</jats:sup>‐Cp*)}<jats:sub>2</jats:sub> (M = Rh, Ir) with <jats:bold>1</jats:bold> gave the κ<jats:sup>1</jats:sup>‐<jats:italic>P</jats:italic>‐monodentate complexes [RuCl<jats:sub>2</jats:sub>(η<jats:sup>6</jats:sup>‐<jats:italic>p</jats:italic>‐cymene)(<jats:bold>1</jats:bold>)] (<jats:bold>5</jats:bold>), [RhCl<jats:sub>2</jats:sub>(η<jats:sup>5</jats:sup>‐Cp*)(<jats:bold>1</jats:bold>)] (<jats:bold>6</jats:bold>) and [IrCl<jats:sub>2</jats:sub>(η<jats:sup>5</jats:sup>‐Cp*)(<jats:bold>1</jats:bold>)] (<jats:bold>7</jats:bold>), respectively, in which the ‐PAd group is non‐coordinating. Chloride abstraction from <jats:bold>6</jats:bold> (or <jats:bold>7</jats:bold>) can be accomplished upon addition of Na[SbF<jats:sub>6</jats:sub>] to generate the cationic κ<jats:sup>2</jats:sup>‐<jats:italic>P,P′</jats:italic>‐chelate complexes <jats:bold>8b</jats:bold> (and <jats:bold>9b</jats:bold>). Alternatively <jats:bold>8a</jats:bold> (or <jats:bold>9a</jats:bold>) could be observed, as their chloride salts, by <jats:sup>31</jats:sup>P{<jats:sup>1</jats:sup>H} NMR spectroscopy upon addition of several drops of CH<jats:sub>3</jats:sub>OH to CDCl<jats:sub>3</jats:sub> solutions of <jats:bold>6</jats:bold> (or <jats:bold>7</jats:bold>). The reaction of <jats:bold>5</jats:bold>–<jats:bold>7</jats:bold> with [AuCl(tht)] gave the dinuclear complexes [κ<jats:sup>2</jats:sup>‐<jats:italic>P,P′</jats:italic>‐μ‐RuCl<jats:sub>2</jats:sub>(η<jats:sup>6</jats:sup>‐<jats:italic>p</jats:italic>‐cymene){Ph<jats:sub>2</jats:sub>P(CH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>PAd(AuCl)}] (<jats:bold>10</jats:bold>), [κ<jats:sup>2</jats:sup>‐<jats:italic>P,P′</jats:italic>‐μ‐RhCl<jats:sub>2</jats:sub>(η<jats:sup>5</jats:sup>‐Cp*){Ph<jats:sub>2</jats:sub>P(CH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>PAd(AuCl)}] (<jats:bold>11</jats:bold>) and [κ<jats:sup>2</jats:sup>‐<jats:italic>P,P′</jats:italic>‐μ‐IrCl<jats:sub>2</jats:sub>(η<jats:sup>5</jats:sup>‐Cp*){Ph<jats:sub>2</jats:sub>P(CH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>PAd(AuCl)}] (<jats:bold>12</jats:bold>). Reaction of two equiv. of <jats:bold>5</jats:bold> with the labile precursors [PdCl<jats:sub>2</jats:sub>(CH<jats:sub>3</jats:sub>CN)<jats:sub>2</jats:sub>] or [PtCl<jats:sub>2</jats:sub>(PhCN)<jats:sub>2</jats:sub>] gave instead the novel trinuclear Ru<jats:sub>2</jats:sub>Pd and Ru<jats:sub>2</jats:sub>Pt complexes <jats:italic>trans</jats:italic>‐[{κ<jats:sup>2</jats:sup>‐<jats:italic>P,P′</jats:italic>‐μ‐RuCl<jats:sub>2</jats:sub>(η<jats:sup>6</jats:sup>‐<jats:italic>p</jats:italic>‐cymene){Ph<jats:sub>2</jats:sub>P(CH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>PAd}}<jats:sub>2</jats:sub>PdCl<jats:sub>2</jats:sub>] (<jats:bold>13</jats:bold>) and <jats:italic>trans</jats:italic>‐[{κ<jats:sup>2</jats:sup>‐<jats:italic>P,P′</jats:italic>‐μ‐RuCl<jats:sub>2</jats:sub>(η<jats:sup>6</jats:sup>‐<jats:italic>p</jats:italic>‐cymene){Ph<jats:sub>2</jats:sub>P(CH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>PAd}}<jats:sub>2</jats:sub>PtCl<jats:sub>2</jats:sub>] (<jats:bold>14</jats:bold>), respectively. All new compounds have been fully characterised by spectroscopic and analytical methods. Furthermore the structures of <jats:bold>3·</jats:bold>CHCl<jats:sub>3</jats:sub>, <jats:bold>4</jats:bold>, <jats:bold>5</jats:bold>, <jats:bold>7·</jats:bold>CHCl<jats:sub>3</jats:sub>, <jats:bold>10·</jats:bold>CH<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub><jats:bold>·</jats:bold>0.5C<jats:sub>2</jats:sub>H<jats:sub>10</jats:sub>O and <jats:bold>13·</jats:bold>2CH<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub> have been elucidated by single‐crystal X‐ray crystallography. The X‐ray structures of <jats:bold>10·</jats:bold>CH<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub><jats:bold>·</jats:bold>0.5C<jats:sub>4</jats:sub>H<jats:sub>10</jats:sub>O and <jats:bold>13·</jats:bold>2CH<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub> demonstrate how nonsymmetric ditertiary phosphane complexes bearing one pendant phosphaadamantane moiety can be used as metalloligands in the controlled syntheses of novel bi‐ and trimetallic complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)</jats:p>