Synthesis, structures, and electronic spectroscopy of luminescent acetylene- and (buta-1,3-diyne)platinum complexes

The electronic absorption and emission spectroscopy of a series of diphenylaceylene- and (buta-1,3-diyne)-Pt0 complexes (L)Pt[(1,2-η2)-R-(C≡C)n-R] and [(dppp)Pt] 2[μ-(1,2-η2):(3,4-η2)-R-(C≡C) 2-R] (R = Ph or CH3, L = dppp or (PPh3) 2, n = 1 or 2) was investigated. The structures of (dppp)Pt[(1,2-η2)-Ph-C≡C-Ph], (dppp)Pt[(1,2- η2)-PhC4Ph] and [(dppp)Pt]2[μ-(1,2- η2):(3,4-η2)-Ph-(C≡C)2-Ph] were characterized by X-ray diffraction. The complexes all display intense absorptions that were attributed to Pt→P(dπ*) and Pt→acetylene(πx*) transitions. Except for the CH 3C4CH3 complexes, the complexes all exhibit two emissions at 380-550 nm and 500-800 nm. The higher energy emission could arise from the 3[P(dπ*)→Pt] transition, and the lower energy emission, which has a longer lifetime than the higher energy one, was attributed to the 3[acetylene(πx*)→Pt] transition. The energy of the MLCT absorption and emission was affected by the electronic properties of the acetylenes and the ancillary phosphanes. KGaA, 2007.