Related Experiment Video
Updated: Sep 19, 2025
14:37
Ambient Method for the Production of an Ionically Gated Carbon Nanotube Common Cathode in Tandem Organic Solar Cells
Published on: November 5, 2014
9.5K
Polarization-Ordered Tandem in Superlattice Promoting C-N Photocatalytic Cross-Coupling
Huiyi Li1, Qinglong Wu1, Lei Li1
1Hefei National Research Center for Physical Sciences at the Microscale, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China.
Journal of the American Chemical Society
|June 9, 2025
Summary
This study introduces a novel superlattice photocatalyst strategy to prevent nickel catalyst deactivation in C-N coupling reactions. The new material enhances charge separation, boosting reaction efficiency and selectivity for pharmaceutical synthesis.
Area of Science:
- Materials Science
- Photocatalysis
- Catalysis
Background:
- Transition metal-catalyzed C-N cross-coupling reactions are vital for synthesizing pharmaceuticals and agrochemicals.
- Nickel catalysts are cost-effective but prone to deactivation, limiting reaction stability.
- Photocatalysis offers a solution, but inefficient charge carrier separation hinders performance.
Purpose of the Study:
- To develop a polarization-ordered tandem strategy using superlattice photocatalysts to improve charge carrier separation.
- To mitigate nickel catalyst deactivation in C-N coupling reactions.
- To enhance the efficiency of photocatalytic processes.
Main Methods:
- Fabrication of Bi4TaO8Cl-Bi2YO4Cl superlattice photocatalysts.
- Characterization using aberration-corrected electron microscopy and atomic-resolution elemental mapping.
- Evaluation of charge carrier dynamics with fluorescence, Kelvin probe, and ultrafast spectroscopy.
Main Results:
- Successful construction of the superlattice structure confirmed by microscopy.
- Ordered polarization tandem significantly lowered exciton binding energy and improved carrier transfer.
- Efficient electron-hole separation effectively suppressed nickel deactivation.
- Achieved 99% conversion and 99% selectivity in pyrrolidine and 4-bromobenzonitrile coupling under visible light within 2 hours.
Conclusions:
- The polarization-ordered tandem strategy enhances charge separation in superlattice photocatalysts.
- This approach effectively suppresses nickel catalyst deactivation in C-N coupling reactions.
- The strategy offers a new pathway for improving traditional photocatalytic processes.
Related Concept Videos
01:26Photochemical Electrocyclic Reactions: Stereochemistry
1.9K
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
1.9K
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.5K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.5K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.1K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.1K
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.2K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.2K
01:27¹H NMR: Long-Range Coupling
2.0K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
2.0K
01:16Cycloaddition Reactions: MO Requirements for Thermal Activation
3.7K
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
3.7K