Strategic Exploration of Quinoline-Based Materials
| Project/Area Number |
22K14670
|
|---|
| Research Category |
Grant-in-Aid for Early-Career Scientists
|
| Allocation Type | Multi-year Fund |
|---|
| Review Section |
Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
|
|---|
| Research Institution | Keio University |
|---|
Principal Investigator |
XU Wei 慶應義塾大学, 薬学部(芝共立), 特任助教 (80869272)
|
|---|
| Project Period (FY) |
2022-04-01 – 2024-03-31
|
| Project Status |
Granted (Fiscal Year 2022)
|
| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2023: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2022: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
|
|---|
| Keywords | metal complex / quinoline / saddle shape / macrocycle / tetradentate / oligomer / catalysis / fluorescence |
|---|
| Outline of Research at the Start |
This project aims at design and synthesis of novel quinoline-based materials for supramolecular chemistry and catalysis developments. The π-wall materials armed with pyridinic nitrogens will exhibit particular physical and chemical properties in molecular recognition and catalysis.
|
| Outline of Annual Research Achievements |
We have designed and synthesized TEtraQuinoline (TEQ), a new family of conjugated macrocycles containing four inwardly oriented nitrogen atoms, which exhibit a rigid saddle-shape structure and special chemical and physical properties. TEQ is synthesized from a cyclic dimer of quinoline-amide substrate and an alkyne in the presence of Tf2O and pyridine derivatives. DFT calculations are carried out to gain a deeper understanding of the reaction mechanism.
The C2-symmetric substituted TEQ has a considerably high energy barrier for flipping to secure its chirality, which has been experimentally confirmed by no erosion of the enantiomeric excess even at 240 °C. TEQ accommodates various types of transition metal cations, such as Fe2+, Co2+, Ni2+, Cu2+, Zn2+ and Pd2+, to form corresponding metal complexes, which displayed high kinetic stability toward cation exchange and protonation. The structure of these complexes are undoubtedly confirmed by X-ray crystallography, and a TEQ-Fe(II) complex exhibits catalytic activity in dehydrogenation reactions with catalyst loadings as low as 0.1 mol%. TEQ shows inherently weak fluorescence, and it becomes strongly emissive upon protonation or addition of upon protonation or addition of Zn(II) cations, suggesting potential application as structurally robust pH or Zn probes.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
I have disclosed potential applications of TEQ/metal complexes as planned.
|
| Strategy for Future Research Activity |
Since C2-symmetric chirality is a unique feature to TEQ in porphyrin family, TEQ-metal complexes will be applied in asymmetric reactions such as olefin cyclopropanation. In addition, these TEQ-metal complexes may be used in high-value chemical transformations, such as CO2 reduction and photochemical water splitting. Polypyridyl/transition metal complexes are one of the most promising class of catalysts in CO reduction. However, the lifetime of these complexes is generally insufficient due to low stability of acyclic ligand systems. The highly rigid and cyclic TEQ architecture holds great potential for the development of a highly durable catalytic system.
TEQ is capable to capture various kinds of transition metal cations, and only Zn-complex exhibits strong fluorescence with high quantum yield. So we expect that TEQ will be used as Zn(II)-based fluorescent probes, which may have practical applications in bioimaging. The development of durable and useful fluorescent probes is highly anticipated through the structural modification with hydrophilic groups. In addition, we expect that TEQ can be modified to the polymer. This kind of functional materials may have application in the purification of contaminated water containing heavy metal ions.
|
Report
(1 results)
Research Products
(8 results)
