Solvent Effect on the Photoinduced Structural Change of a Phosphorescent Molecular Butterfly.

Photoinduced structural changes (PSC) is one of the fundamental excited-state dynamic processes, and yet often very challenging to distinguish from competing electronic excited-state relaxation channels having similar or even comparable timescales. Here, we report a detailed study on the PSC of a pyrazolate bridged platinum(II) binuclear complex, BFPtPZ (C^NPt(μ-pz') PtC^N, C^N=2-(2,4-difluorophenyl)pyridine, pz'=pyrazolate), a molecular butterfly, using time-correlated single photon counting measurements at different wavelengths and sample temperatures. Analysis of the results obtained using dichloromethane (DCM) and ethylene carbonate (EC) as solvents enabled us to reveal an unexpected, strong solvent effect on the PSC processes.