Some molecular rods:: gold(I) complexes of 1,3-diynes.: Crystal structures of Au(C≡CC≡CH)(PPh3) and {Cu3(μ-dppm)3}(μ3-I)(μ3-C≡CC≡CAuC≡CC≡CH)

Reaction of buta-1,3-diyne with AuCl(PPh3) and (AuCl)(2) (mu-dppm) in the presence of base gave the diynyl complexes Au(C=C=H)(PPh3) 1 and {Au(C=CC=CH)}(2) (mu-dppm) 2, respectively. Similar reaction of W(C=CC=CH)(CO)(3)Cp with the two gold(I) complexes gave the heteronuclear diyndiyls W{C=CC=C[Au(PPh3]}(CO)(3)Cp (known) and {Au(C=CC=C[W(CO)(3)Cp])}(2) (mu-dppm) 3. Reaction of [ppn][ Au(acac)(2)] with the appropriate diynes a afforded [ppn][Au(C=CC=CH)(2)] 4, [ppn][ Au{C=CC=C[W(CO)(3)Cp]}(2)] 5, [ppn][Au{C=CC=C[Au(PPh3)]}(2)] 6 and [ppn][Au(C=CC6H4 C=CPh)(2)] 7; the latter anion was also obtained as the very unstable NMe4 salt. The reaction between 2 and {Au(OTf)}(2) (mu-dppm) likely afforded cyclo-{Au-2 (mu-C=CC=C)(mu-dppm)}(2) 8, although this compound was not structurally characterised. On one occasion, the molecular rod {Cu-3 (mu-dppm)(3)}(mu(3)-I)(mu(3)-eta(1)-C=CC=CAuC=CC=CH) 9 was isolated and crystallographically characterised; a rational approach to 8 from [ppn][Au(C=CC=CH)(2)] and [{Cu-3 ( mu-dppm)(3)}(mu(3)-I)(2)]I gave instead the molecular dumbbell [{Cu-3 (mu(3)-I)(mu-dppm)(3)}(2) (mu(3) :mu(3)-C=CC=CAuC=CC=C)] I 10.