Synthesis of Monodisperse Platinum Acetylide Oligomers End-Capped with Naphthalene Diimide Units

摘要

We report the synthesis and structural characterization of a series of monodisperse platinum acetylide oligomers with the general structure NDI-[Ph-C equivalent to C-Pt(PBU3)(2)-C=-C-](n)-Ph-NDI, where n = 2, 3, 6, or 10, Ph = 1,4-phenylene, NDI is a substituted 1,4,5,8-tiaplithalene diimide, and the geometry at the Pt centers is trans. The oligomers were synthesized via an iterative-convergent approach utilizing organometallic synthons that feature orthogonally protected terminal acetylene units. The P-31 NMR spectra of the oligomers are especially revealing as to their structure, due to a difference in chemical shift for the internal and terminal Pt(PBU3)(2) units. The oligomers were also characterized by electrochemistry, UV-visible absorption, and photoluminescence spectroscopy. The emission spectroscopy reveals that the triplet exciton is efficiently quenched in the NDI end-capped oligomers, and the quenching is thought to arise due to photoinduced charge separation.