The 3(ππ*) emission of Cy3PAu(C=C)nAuPCy3 (n=3, 4).: Effect of chain length upon acetylenic 3(ππ*) emission

The Cy3PAu(CdropC)(n)AUPCy(3) (n = 3 (3), 4 (4)) complexes were prepared by the reaction of Me3Si(CdropC)(n)SiMe3 (n = 3, 4) with Cy3PAuCl in the presence of NaOH. The molecular structure of 3.H2Cl2 was determined by X-ray crystallography. Complexes 3 and 4 show vibronically structured acetylenic (3)(pipi*) emission with v(0-0) values of 19 920 and 17 420 cm(-1), respectively; hence, v(0-0) for Cy3PAu(CdropC) infinityAuPCy3 can be estimated at similar to11000 cm(-1) from the plot of v(0-0) versus 1 /n.