Methanol-Triggered Turn-On-Type Photoluminescence in l -Cysteinato Palladium(II) and Platinum(II) Complexes Supported by a Bis(diphenylphosphine) Ligand

The selective detection of methanol by photoluminescence under environmental conditions has been a great challenge for materials science. Herein, a reversible, turn-on-type photoluminescence triggered by methanol vapor in square-planar palladium(II) and platinum(II) complexes, newly prepared from [MCl₂(1,3-bis(diphenylphosphino)propane)] and l-cysteine, is reported. Both the turn-on and turn-off states of the complexes were crystallographically characterized, which revealed the presence of intermolecular OH···O and CH··· interactions between methanol and the complex molecules in the turn-on state. These interactions prevent the vibrational quenching of the luminescence, leading to the turn-on-type luminescence in this system.