Multiple ligand-based emissions from a platinum(II) terpyridine complex attached to pyrene

Attaching an electron-rich aryl substituent at the 4' position of the trpy ligand in Pt(trpy)Cl+ endows the low-lying excited state with intraligand charge-transfer (ILCT) character, enhances the emission intensity, extends the excited-state lifetime, and inhibits exciplex quenching by Lewis bases. When pyrene is the substituent, the complex exhibits singlet- and triplet-state emission and the lifetime extends to 64 mu s in room-temperature dichloromethane solution.