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···π 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.