Abstract
The development of stimuli-responsive amphiphilic supramolecular nanostructures is an attractive target for systems based on light-absorbing chromophores that can function as photosensitizers in water. We report here on a water soluble supramolecular carboxylated perylene monoimide system in which charge can be switched significantly by a change in pH. This was accomplished by substituting the perylene core with an ionizable hydroxyl group. In acidic environments, crystalline supramolecular nanoribbons with dimensions on the order of 500 × 50 × 2 nm form readily, while in basic solution the additional electrostatic repulsion of the ionized hydroxyl reduces assemblies to very small dimensions on the order of only several nanometers. The HOMO/LUMO levels were also found to be sensitive to pH; in acidic media the HOMO/LUMO levels are -5.65 and -3.70 eV respectively versus vacuum, whereas is in basic conditions they are -4.90 and -3.33 eV, respectively. Utilizing the assemblies as photosensitizers in photocatalytic production of hydrogen with [Mo3S13]2- as a catalyst at a pH of 4, H2 was generated with a turnover number of 125 after 18 hours. Charge switching the assemblies at a pH of 9-10 and using an iron porphyrin catalyst, protons could again be reduced to hydrogen and CO2 was reduced to CO with a turnover number of 30. The system investigated offers an example of dynamic photosensitizing assemblies that can drive reactions in both acidic and basic media.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 5779-5786 |
| Number of pages | 8 |
| Journal | Chemical Science |
| Volume | 10 |
| Issue number | 22 |
| DOIs | |
| State | Published - 2019 |
Funding
This work was supported as part of the Argonne-Northwestern Solar Energy Research (ANSER) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Basic Energy Sciences under Award # DESC0001059. Determination of Electronic Energy levels and DFT calculations were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under award no. DE-FG02-00ER45810. Molecular dynamic simulations were possible thanks to the generous support from the Department of Energy, under award no. DE-FG02-08ER46539. Use of the Advanced Photon Source (APS) was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Solution X-ray experiments were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by Northwestern University, E.I. DuPont de Nemours & Co., and The Dow Chemical Company. Use of Advanced Photon Source Sector 8-ID-E, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. The authors thank Dr J. Strzalka for help with GIWAXS setup and measurements at Argonne National Lab. We thank the Biological Imaging Facility (BIF) at Northwestern for the use of TEM equipment. The Electron Probe Instrumentation Center (EPIC) facilities of the Northwestern University Atomic and Nanoscale Characterization Experimental (NUANCE) Center for the use of AFM equipment. NMR and MS equipment at the Integrated Molecular Structure Education and Research Center (IMSERC) which was supported by the So and Hybrid Nanotechnology Experimental (SHyNE) NSF ECCS-1542205, National Science Foundation under CHE-9871268, the State of Illinois and International Institute of Nanotechnology (IIN). This UPS work was performed in the Keck-II facility of NUANCE Center at North-western University. The NUANCE Center at Northwestern University has received support from the SHyNE Resource (NSF NNCI-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois.
ASJC Scopus subject areas
- General Chemistry