A chemist at Washington University in St. Louis and his colleagues has taken an elegant chemical approach to turn a nonfluorescent organometallic complex into a strong emitter by hampering its internal rotations at the molecular level. Dewey Holten, Ph.D., Washington University professor of chemistry, Jonathan Lindsey, Ph.D., of North Carolina State University and David Bocian, Ph.D., University of California, Riverside, have made a molecule photoluminescent by hindering its intramolecular rotation.
A molecule “pumped” to its excited states by light may nonradiatively return to the ground state via deactivation processes driven by intramolecular motions. Limiting conformational freedom or enhancing structural rigidity of the molecule may block its nonradiative pathways and make it emissive.
“These insights establish a foundation for tuning the photophysical properties of these chromophores for use in diverse photochemical applications,” said Holten.
The Holten paper, “Structural Control of the Excited-State Dynamics of Bis(dipyrrinato)zinc Complexes: Self-Assembling Chromophores for Light-Harvesting Architectures” (J. Am.Chem. Soc.; Volume 126, Issue 9, Pages 2664 – 2665) has been highlighted by Heart Cut, a news magazine published electronically by the American Chemical Society (ACS) and available at their Web site.