Platinum(II) and mixed platinum(II)/gold(I) σ-alkynyl complexes.: The first anionic σ-alkynyl metal polymers

The alkynes C6Me4(C=CH)(2)-1,4, C6Me4(C=CH)(2)-1,2, and C6Me3(C=CH)(3)-1,3,5 react with cis-[PtCl2(PAr3)(2)] and NHEt2 and a catalytic amount of CuI to give complexes trans-[Pt(C=CC6Me4C=CH-4)(2)(PAr3)(2)] [Ar = Ph (1a), C6H4Me-4 (To) (1b)], trans- [Pt(C=CC6Me4-C equivalent to CH-2)(2)(PAr3)(2)] [Ar = Ph (2a), To (2b)], and trans-[Pt{C equivalent to CC6Me3(C equivalent to CH)(2)-3,5}(2)(PAr3)(2)] [Ar = Ph (3a), To (3b)], respectively. The reactions of [Au(acac)PAr3] (acac = acetylacetonato) with complex la or 1b (2:1) or with 3b (4:1) give the neutral mixed (PtAu2I)-Au-II or PtIIAu4I sigma-alkynyl complexes trans-[Pt(C=-CC6Me4C equivalent to CAuPAr3-4)(2)(PAr3)(2)] [Ar = Ph (4a), To (4b)] or trans- [Pt{C equivalent to CC6Me3(C equivalent to CAuPTo(3))(2)-3,5}(2)(PTo(3))(2)] (5b), respectively. Additionally, the replacement of the triarylphosphine ligands present in la, 2a, 4b, or 5b with various trialkylphosphines produces the homologous derivatives with PMe3 (1c, 2c, 4c, 5c), PEt3 (1d), or P(Bu-n)(3) (1e), respectively. PPN[Au(acac)(2)] reacts with complex 1a, 1c, or 1e (1:1) to give (PPN)(n)-(1e), [trans-Ptf(C=CC6Me4C=C-4)2Aul(PR3)(2)](n) [R = Ph (6a), Me Bu (6e)], while its reaction with 3b (2:1) produces (PPN)2n[trans-PtIC=CC6Me3(C=C)2-3 5Au(2)(PTo(3))2]n (7). Complexes 6a, 6c, 6e, and 7 are the first anionic sigma-alkynyl metal polymers described so far. The crystal structures of 1a-CHCl3, 2b-2CHCl(3), and 4b-5CH(2)Cl(2) have been determined. Each complex displays crystallographic inversion symmetry.