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)‐Pt 0 complexes (L)Pt[(1,2‐η 2 )‐R–(C≡C) n –R] and [(dppp)Pt] 2 [μ‐(1,2‐η 2 ):(3,4‐η 2 )‐R–(C≡C) 2 –R] {R = Ph or CH 3 , L = dppp or(PPh 3 ) 2 , n = 1 or 2} was investigated. The structures of(dppp)Pt[(1,2‐η 2 )‐Ph–C≡C–Ph], (dppp)Pt[(1,2‐η 2 )‐PhC 4 Ph] and [(dppp)Pt] 2 [μ‐(1,2‐η 2 ):(3,4‐η 2 )‐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(π x *) transitions. Except for the CH 3 C 4 CH 3 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(π x *)→Pt] transition. The energy of the MLCT absorption and emission was affected by the electronic properties of the acetylenes and the ancillary phosphanes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)