(ISOCYANOARYL)ACETYLIDES AS BRIDGING LIGANDS IN RIGID-ROD POLYMERS - MONONUCLEAR AND OLIGONUCLEAR GOLD(I) COMPLEXES

The new ethynylaryl isocyanide ligands 4-C = NC6H4C = CH (1a) and 4-C = N-3-MeC6H3-C = CH (1b) have been prepared. They react with [AuCl(SMe2)] and with [(AuC = C-t-Bu)x] to give the isocyanide complexes [ClAu(4-C = NArC = CH)] (2a, Ar = C6H4; 2b, Ar = 3-MeC6H3) and [t-BuC = CAu(4-C = NArC = CH)] (6a, Ar = C6H4; 6b, Ar = 3-MeC6H3), respectively. The complex [t-BuC = CAuC = NXy] (Xy = 2,6-Me2C6H3) reacts with the acidic alkyne 4-NO2-C6H4C = CH to give t-BuC = CH and [4-NO2C6H4C = CAuC = NXy]. A similar reaction uses the more acidic alkyne in 6 to displace t-BuC=CH from 6 and so give the linear rigid-rod oligomers [t-BuC = C(Au = NArC = C-)(x)H] (7a, Ar = C6H4; 7b, Ar = 3-MeC6H3). The complexes 2a and 6b have been characterized by X-ray structure determinations (2a, monoclinic, P2(1)/m, a = 10.042(2) angstrom, b = 7.067(2) angstrom, c = 6.596(1) angstrom, beta = 98.79(2)-degrees, V = 462.6(1) angstrom3, Z = 2, R = 0.0427, R(w) = 0.0402; 6b, monoclinic, P2(1)/n, a = 14.225(4), b = 16.196(4), c = 6.747(2) angstrom, beta = 93.86(3)-degrees, V = 1551.0(8) angstrom3, Z = 4, R = 0.0332, R(w) = 0.0396), while the oligomers 7 have been characterized by elemental analysis and by comparison of the IR and XPS parameters with those of the model compounds 6.