Geometric Influence on Intramolecular Photoinduced Electron Transfer in Platinum(II) Acetylide‐Linked Donor–Acceptor Assemblies

A new donor–acceptor system, in which the electron donor triphenylamine (TPA) and the electron acceptor C 60 are bridged through a cis‐ or trans‐ platinum(II) acetylide spacer have been prepared. Ground‐state studies were conducted using electrochemistry and UV/Vis spectroscopy. Fluorescence studies suggested that charge transfer is the deactivation mechanism for the singlet excited state, and this was verified by transient absorption spectroscopy. Selective photoexcitation of 1 and 2 at 387 nm leads to a fast charge transfer between the TPA and C 60 , which gives rise to a radical ion‐pair state (TPA .+ –Pt–C 60 .− ). Our results suggest that charge transfer is favored for the cis configuration while the presence of the trans configuration in the Pt II diacetylide results in a longer‐lived charge separated states.