Photophysics and electrochemistry of a platinum-acetylide disubstituted perylenediimide

The synthesis and photophysical study of a perylene diimide (PDI) functionalised with platinum acetylide units of the type, trans {-C&z.tbd;C-Pt(PBu 3 ) 2 -C&z.tbd;C-Ph} and comparison with a phenylacetylide substituted model compound are reported. The model compound demonstrates typical perylene absorption and photoluminescence spectra characteristic of singlet excited state formation and decay. The Pt-substitution, however, appears to induce spin-orbit coupling into the chromophore and giving rise to a triplet excited state which was confirmed by transient absorption measurements. This excited state is quenched by oxygen, leading to the formation of singlet oxygen in dichloromethane, recorded by time-resolved near-infrared luminescence measurements. Photophysical studies of a perylene diimide (PDI) functionalised with platinum acetylide units reveal the formation of a triplet state upon excitation.