Spinning in Place

摘要

Phosphorescent materials glow for a long time because their emission of light requires a change in spin state. Spin conservation is a pivotal principle in the interpretation of optical absorption and emission spectra of isolated molecular chromophores. Guo et al. (p. 1684) now show that the principle can also account for energy transfer dynamics between chromophores. Two different bimetallic complexes were synthesized that had been designed to facilitate energy transfer between spectrally overlapping donor and acceptor ions. The ligands and donors were the same in both complexes, but the acceptor ions varied in their spin state. Photoexcitation led to energy transfer only in the complex with spin-compatible donor and acceptor sites.