Synthesis of Securingine B Enables Photoresponsive Materials Design
Research Background
Natural products have long played a crucial role in drug discovery, providing many biologically active compounds and fundamental principles for drug development. However, the synthetic exploration of natural products is not limited to the pharmaceutical field; their applications in materials science are gradually gaining attention. Particularly, natural products with photoresponsive properties have attracted significant interest due to their potential applications in photoswitching materials and photoresponsive liquid crystals.
Securingine B is a contra-thermodynamic natural product, and its synthesis has been a challenging subject. Compared to its thermodynamically more stable isomer, secu’amamine D, the synthesis of securingine B requires overcoming thermodynamic bias. Previous studies have shown that secu’amamine D can be converted into securingine B through photochemical transformation, but the detailed mechanism and application potential of this process have not been fully explored. Therefore, a research team from the Korea Advanced Institute of Science and Technology (KAIST) focused on synthesizing securingine B via photochemical methods and developing novel photoresponsive materials based on this.
Research Source
This paper was co-authored by Sangbin Park, Gyumin Kang, Wantae Kim, and other researchers from KAIST, with Dong Ki Yoon and Sunkyu Han as the corresponding authors. The paper was published on March 13, 2025, in the journal Chem, titled “Synthesis of Securingine B Enables Photoresponsive Materials Design.” The research was supported by the National Research Foundation of Korea.
Research Process and Results
1. Photochemical Synthesis of Securingine B
The research team first achieved the conversion of secu’amamine D to securingine B through photochemical methods. They found that irradiating a solution of secu’amamine D with 427 nm blue light in the presence of the photosensitizer thioxanthone yielded securingine B with a high efficiency of 90%. Additionally, under 370 nm UV light irradiation, even without a photosensitizer, the yield of securingine B reached 80%. These results demonstrate that photochemical methods can effectively achieve the conversion of secu’amamine D to securingine B.
To further validate the generality of this reaction, the team conducted similar photochemical experiments on phyllantidine and successfully achieved its conversion to the contra-thermodynamic product. Through density functional theory (DFT) calculations, the team revealed the mechanism of this photochemical reaction: after photoexcitation, secu’amamine D generates a triplet intermediate, which undergoes C-O bond homolysis to form a diradical intermediate, ultimately leading to the formation of securingine B through radical recombination.
2. Thermodynamic Reverse Reaction
The research team also discovered that securingine B can be converted back to secu’amamine D under heating conditions. When a solution of securingine B was heated to 130°C, the yield of secu’amamine D reached 93%. This indicates that secu’amamine D and securingine B can undergo reversible transformations under light and heat stimuli, providing a theoretical foundation for the development of novel photoresponsive materials.
3. Development of Photochromic Materials
Based on the findings of the photochemical reaction, the research team designed a novel photochromic material. By introducing an electron-donating group into the conjugated ester moiety of phyllantidine, they constructed a push-pull system. This material rapidly changes from yellow to colorless under blue light irradiation and reverts to yellow under 310 nm UV light. The photochromic conversion time of this material is short, and it exhibits high quantum yield, demonstrating excellent photoresponsive performance.
4. Photoresponsive Chiral Dopant for Liquid Crystals
The research team also developed a photoresponsive chiral dopant for liquid crystals based on securingine B. By introducing a pyrene moiety into phyllantidine, they designed a molecule capable of structural rearrangement under light and heat stimuli. This chiral dopant significantly alters the helical structure of liquid crystals and can reversibly modulate the optical properties of liquid crystals under blue light irradiation. This discovery provides a new tool for dynamically controlling the optical properties of liquid crystals.
Research Conclusions and Significance
This study successfully achieved the first synthesis of securingine B and revealed the mechanism of photochemical and thermodynamic reversible transformation between securingine B and secu’amamine D. Based on this discovery, the research team developed novel photochromic materials and photoresponsive chiral dopants for liquid crystals, showcasing the broad application potential of natural products in materials science.
The scientific value of this research lies in not only providing new methods for the synthesis of natural products but also opening new directions for the design of photoresponsive materials. In particular, the synthesis of contra-thermodynamic products through photochemical methods offers new insights for developing photoswitching materials with specific functionalities. Additionally, the photoresponsive chiral dopant developed by the research team has potential applications in liquid crystal display technology, enabling dynamic modulation of the optical properties of liquid crystals through external stimuli.
Research Highlights
- First Synthesis of Securingine B: Successfully synthesized the contra-thermodynamic securingine B through photochemical methods, filling a research gap in this field.
- Photochemical and Thermodynamic Reversible Transformation: Revealed the reversible transformation mechanism between secu’amamine D and securingine B, providing a theoretical foundation for the development of photoresponsive materials.
- Novel Photochromic Material: Designed a photochromic material with excellent photoresponsive performance based on the natural product framework, demonstrating its potential application in photoswitching materials.
- Photoresponsive Chiral Dopant for Liquid Crystals: Developed a chiral dopant capable of dynamically modulating the optical properties of liquid crystals under light and heat stimuli, offering a new tool for liquid crystal display technology.
This research not only advances the field of natural product synthesis but also provides new ideas and tools for the design of photoresponsive materials in materials science, holding significant scientific and application value.