Related Experiment Video
Updated: Jul 6, 2026
07:09
Förster Resonance Energy Transfer Mapping: A New Methodology to Elucidate Global Structural Features
Published on: March 16, 2022
Distinguishing between Dexter and rapid sequential electron transfer in covalently linked donor-acceptor assemblies
Monica Soler1, James K McCusker
1Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
Journal of the American Chemical Society
|March 18, 2008
Summary
This study investigates manganese (Mn) and zinc (Zn) complexes linked to ruthenium (Ru) chromophores, revealing Dexter energy transfer as the primary pathway for excited-state reactions in Mn complexes. This finding highlights the importance of variable-temperature measurements for distinguishing energy transfer mechanisms.
Area of Science:
- Coordination Chemistry
- Photophysics
- Materials Science
Background:
- Dinuclear metal complexes offer unique electronic properties.
- Ruthenium polypyridyl complexes are widely studied for their photophysical behavior.
- Understanding energy transfer mechanisms is crucial for designing functional materials.
Purpose of the Study:
- To synthesize and characterize novel dinuclear metal complexes featuring a Ru(II) polypyridyl unit.
- To investigate the photophysical properties and excited-state dynamics of these complexes.
- To elucidate the dominant energy transfer pathway (Dexter vs. electron transfer) in manganese-containing complexes.
Main Methods:
- Synthesis of dinuclear metal complexes with general formula [M2(L)(mcb)(Ru(4,4'-(X)2-bpy)2)](PF6)3.
- Photophysical characterization including emission lifetime and quantum yield measurements.
- Variable-temperature time-resolved absorption and emission spectroscopy.
Main Results:
- Manganese complexes exhibited significantly shorter excited-state lifetimes compared to their zinc analogs.
- Variable-temperature emission data for a Mn complex fit a model consistent with Dexter energy transfer.
- Electronic coupling constants for Dexter transfer varied significantly based on excited-state localization.
Conclusions:
- Dexter energy transfer is the dominant excited-state reaction pathway in the studied manganese complexes.
- The proximity of the donor excited state to the dimanganese acceptor influences Dexter transfer efficiency.
- Variable-temperature measurements are essential for differentiating Dexter and electron transfer mechanisms.
Related Concept Videos
01:19Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:43Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
01:28Electron Transport Chains
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle.
The ETC is comprised of...
The ETC is comprised of...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...