2019 Fiscal Year Research-status Report
Stimuli-responsive polymers through new dynamic metal complexes
| Project/Area Number |
18K05247
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| Research Institution | Okinawa Institute of Science and Technology Graduate University |
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Principal Investigator |
クスヌディノワ ジュリア 沖縄科学技術大学院大学, 錯体化学・触媒ユニット, 准教授 (90747544)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | mechanophore / Cu complexes / dynamic ligand / stress sensor / cross linked polymers / N-heterocyclic carbene / pyridinophane / mechanoresponse |
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| Outline of Annual Research Achievements |
During fiscal year 2019, results were published on Cu-containing dynamic mechanophores incorporated as cross linkers into polybutylacrylate films. In particular, the following goals have been achieved:
a) Development and full characterization of Cu-NHC complexes with dynamic pyridinophane ligand and study of their air stability
b) Incorporation of Cu-NHC complexes as cross linkers into polyacrylate films. Detection of mechanical stress via reversible change of photoluminescence intensity. Highly sensitive stress detection as been achieved superior to majority of literature reported systems, with fully reversible response. This is due to dynamic nature of mechanophore, as well as the attachment of mechanophores as short cross-linkers instead of incorporating into a linear polymer chain.
Screening showed that only Cu-NHC complexes with moderate steric bulk at pyridinophane and NHC ligands show optimal response, and very bulky complexes are less sensitive. Therefore, we have found that simply increasing photoluminescence brightness is not a suitable approach, and search for optimal dynamic properties is needed.
In another direction, we synthesized several Co complexes as model compounds that can show change of spin density localization depending on steric hindrance. We plan to further attach these complexes to polymer films. To complete this project, further optimization of synthetic conditions for synthesis of polymer-attached complexes will be needed. We also started another direction using Cu-based mechanophores to detect mechanical stress in rigid polymer films.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
According to the initial plan, we optimized and published the results on Cu-based sensitive mechanophores as cross-linkers in polyacrylates in Chemical Communications. Based on this work, we also submitted one patent application for Cu-based mechanophores for stress detection in cross-linked polymers and it is currently under approval process expected to finish in fiscal year 2020. We are also in the process of establishing collaboration with a chemical company, currently delayed due to COVID outbreak.
During this fiscal year, we started new project on using Co complexes that can show spin state change in model compounds and this work is currently in progress and will require more synthetic optimization.
We also plan to complete another manuscript based on using structurally similar dynamic Cu complexes with pyridinophane ligands incorporated into polymers for detection of ethylene gas via visually detected color changes.
Now we are preparing another manuscript and a patent application on using Cu-mechanophores in rigid polymer films and plan to submit the manuscript in fiscal year 2020. This manuscript is currently almost complete, however, a few additional measurements will need to be completed in order to proceed with submission.
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| Strategy for Future Research Activity |
Future work will be conducted according to following plan:
a) Complete measurements and submit manuscript and patent application on using Cu mechanophores for mechanical damage detection in rigid polymer films. Currently final measurements of quantum yield are needed to complete the manuscript and patent preparation.
b) Examine Co complexes as possible mechanophores for stress detection in polymers. Model systems show that Co complexes may change localization of spin density between metal-based and ligand-based radical state in catecholate complexes. This leads to different color and spectroscopic features in near-IR region, that can be used as a basis for stress detection via absorbance spectroscopy or color changes
c) We plan to utilize Fe complexes with pyridinophane ligands as mechanophores in polymers. Model study shows that spin crossover happens depending on steric hindrance, and we plan to obtain mechanoresponsive features when these complexes are attached to polymer based on spin crossover effect. Different spin state may lead to different ability to quench photoluminescence of mechanically incorporated luminophores, that can be used to detect stress in polymers.
d) We plan to utilize other types of mechanophores for stress detection
e) We recently optimized conditions for synthesis of cross linked polymers and obtained pyridinophane ligands with shorter cross-linker length. We will further continue optimization studies to obtain more sensitive response and good homogeneity of the mechanophore distribution
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| Causes of Carryover |
The actual expenditure in the fiscal year was overall the same as planned, with small amount remaining. The remaining amount of 14,071 yen is to be used for purchasing chemicals and research materials in the next fiscal year.
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| Remarks |
(3) is a Japanese translation of (2)
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[Presentation] Mechanoresponsive photoluminescence in cross-linked polybutylacrylates containing flexible (pyridinophane)Cu(NHC) complexes as mechanophores2020
Author(s)
Karimata, A., Patil. P., Lapointe, S., Khaskin, E., Fayzullin, R. R., & Khusnutdinova, J. R.
Organizer
100th Annual Meeting 2020 of the Chemical Society of Japan
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[Presentation] Photoluminescent pyridinophane copper(I) complexes bearing NHC ligand and their applications in mechanical-stimuli responsive cross-linked polymer materials2019
Author(s)
Karimata, A., Patil. P., Lapointe, S., Khaskin, E., Fayzullin, R. R., & Khusnutdinova, J. R.
Organizer
Japanese Society of Coordination Chemistry
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