Emissive Platinum(II) Macrocycles as Tunable Cascade Energy Transfer Scaffolds
Koushik Acharyya, Soumalya Bhattacharyya, Shuai Lü, Yan Sun, Partha Sarathi Mukherjee, Peter J. Stang
Abstract
Abstract Developing artificial light‐harvesting scaffolds with a cascade energy transfer process is significant for better understanding of photosynthesis. Here, we report [3+3] self‐assembled Pt II fluorescent macrocycles ( 3 a and 3 b ) as light‐harvesting platforms with cascade energy transfer. The Pt II macrocycles aggregate into nanospheres and show emission‐enhancement characteristics upon increasing water content in acetone medium. These aggregates ( 3a a and 3b a ) serve as energy donors when mixed with the hydrophobic dye Eosin‐Y (ESY). In the presence of a second dye, Nile Red (NiR), an unusual sequential two‐step energy transfer takes place from the macrocycles to NiR. In this case, ESY acts as a bridge in the relay mode. Additionally, a unique strategy to control such an energy transfer process by tuning the chain length of the alkyl group attached to the periphery of the macrocycles is demonstrated.