En route to diplatinum polyynediyl complexes trans,trans-(Ar)(R3P)2Pt(C≡C)nPt(PR3)2(Ar): Untold tales, including end-group strategies

<jats:title>Abstract</jats:title> <jats:p>Reactions of {(C<jats:sub>6</jats:sub>F<jats:sub>5</jats:sub>)Pt[S(CH<jats:sub>2</jats:sub>CH<jats:sub>2</jats:sub>-)<jats:sub>2</jats:sub>](μ-Cl)}<jats:sub>2</jats:sub> and R<jats:sub>3</jats:sub>P yield the bis(phosphine) species <jats:italic>trans</jats:italic>-(C<jats:sub>6</jats:sub>F<jats:sub>5</jats:sub>)(R<jats:sub>3</jats:sub>P)<jats:sub>2</jats:sub>PtCl [R = Et (<jats:bold>Pt'Cl</jats:bold>), Ph, (<jats:italic>p</jats:italic>-CF<jats:sub>3</jats:sub>C<jats:sub>6</jats:sub>H<jats:sub>4</jats:sub>)<jats:sub>3</jats:sub>P; 88-81 %]. Additions of <jats:bold>Pt'Cl</jats:bold> and H(C≡C)<jats:italic> <jats:sub>n</jats:sub> </jats:italic>H (<jats:italic>n</jats:italic> = 1, 2; HNEt<jats:sub>2</jats:sub>, 20 mol % CuI) give <jats:bold>Pt'C<jats:sub>2</jats:sub>H</jats:bold> (37 %, plus <jats:bold>Pt'I</jats:bold>, 16 %) and <jats:bold>Pt'C<jats:sub>4</jats:sub>H</jats:bold> (88 %). Homocoupling of <jats:bold>Pt'C<jats:sub>4</jats:sub>H</jats:bold> under Hay conditions (O<jats:sub>2</jats:sub>, CuCl, TMEDA, acetone) gives <jats:bold>Pt'C<jats:sub>8</jats:sub>Pt'</jats:bold> (85 %), but <jats:bold>Pt'C<jats:sub>2</jats:sub>H</jats:bold> affords only traces of <jats:bold>Pt'C<jats:sub>4</jats:sub>Pt'</jats:bold>. However, condensation of <jats:bold>Pt'C<jats:sub>4</jats:sub>H</jats:bold> and <jats:bold>Pt'Cl</jats:bold> (HNEt<jats:sub>2</jats:sub>, 20 mol % CuI) yields <jats:bold>Pt'C<jats:sub>4</jats:sub>Pt'</jats:bold> (97 %). Hay heterocouplings of <jats:bold>Pt'C<jats:sub>4</jats:sub>H</jats:bold> or <jats:italic>trans</jats:italic>-(<jats:italic>p</jats:italic>-tol)(Ph<jats:sub>3</jats:sub>P)<jats:sub>2</jats:sub>Pt(C≡C)<jats:sub>2</jats:sub>H (<jats:bold>Pt*C<jats:sub>4</jats:sub>H</jats:bold>) and excess HC≡CSiEt<jats:sub>3</jats:sub> give <jats:bold>Pt'C<jats:sub>6</jats:sub>SiEt<jats:sub>3</jats:sub> </jats:bold> (76 %) or <jats:bold>Pt*C<jats:sub>6</jats:sub>SiEt<jats:sub>3</jats:sub> </jats:bold> (89 %). The latter and wet <jats:italic>n</jats:italic>-Bu<jats:sub>4</jats:sub>N<jats:sup>+</jats:sup> F<jats:sup>-</jats:sup> react to yield labile <jats:bold>Pt*C<jats:sub>6</jats:sub>H</jats:bold> (60 %). Hay homocouplings of <jats:bold>Pt*C<jats:sub>4</jats:sub>H</jats:bold> and <jats:bold>Pt*C<jats:sub>6</jats:sub>H</jats:bold> give <jats:bold>Pt*C<jats:sub>8</jats:sub>Pt*</jats:bold> (64 %) and <jats:bold>Pt*C<jats:sub>12</jats:sub>Pt*</jats:bold> (64 %). Reaction of <jats:italic>trans</jats:italic>-(C<jats:sub>6</jats:sub>F<jats:sub>5</jats:sub>)(<jats:italic>p</jats:italic>-tol<jats:sub>3</jats:sub>P)<jats:sub>2</jats:sub>PtCl (<jats:bold>PtCl</jats:bold>) and HC≡CH (HNEt<jats:sub>2</jats:sub>, 20 mol % CuI) yields only traces of <jats:bold>PtC<jats:sub>2</jats:sub>H</jats:bold>. However, an analogous reaction with HC≡CSiMe<jats:sub>3</jats:sub> gives <jats:bold>PtC<jats:sub>2</jats:sub>SiMe<jats:sub>3</jats:sub> </jats:bold> (75 %), which upon treatment with silica yields <jats:bold>PtC<jats:sub>2</jats:sub>H</jats:bold> (77 %). An analogous coupling of <jats:italic>trans</jats:italic>-(C<jats:sub>6</jats:sub>F<jats:sub>5</jats:sub>)(Ph<jats:sub>3</jats:sub>P)<jats:sub>2</jats:sub>PtCl with H(C≡C)<jats:sub>2</jats:sub>H gives <jats:italic>trans</jats:italic>-(C<jats:sub>6</jats:sub>F<jats:sub>5</jats:sub>)(Ph<jats:sub>3</jats:sub>P)<jats:sub>2</jats:sub>Pt(C≡C)<jats:sub>2</jats:sub>H (34 %). Advantages and disadvantages of the various <jats:italic>trans</jats:italic>-(Ar)(R<jats:sub>3</jats:sub>P)<jats:sub>2</jats:sub>Pt end-groups are analyzed.</jats:p>