Photophysical Properties of Visible‐Light‐Harvesting PtII Bis(acetylide) Complexes

Abstract

PtII complexes have attracted much attention due to their readily derivatizable molecular structures and efficient production of triplet excited states and have been extensively used in many areas. Conventional PtII complexes usually exhibit small molar absorption coefficients in the visible spectral region, and the triplet excited state lifetimes are short. However, for applications such as photocatalysis, triplet–triplet annihilation (TTA) upconversion, nonlinear optics, etc., visible‐light‐harvesting PtII bis(acetylide) complexes with long‐lived triplet excited state are cucial. We summarize strategies directed towards achieving these goals, through the attachment of appropriate strong visible‐light‐harvesting organic chromophores to the ligand to switch the S0→1MLCT (metal‐to‐ligand charge transfer) transition to the S0→1IL (intraligand) transition (π–π*) and to switch the lowest triplet excited state from the 3MLCT to the 3IL state. We also summarize the properties of PtII bis(acetylide) complexes that show broadband absorption and reverse saturate absorption for application in nonlinear optics. Singlet and triplet energy transfer and localization of the triplet excited state in multiple‐chromophore complexes are also discussed.