| 1. |
- Baggi, Nicolò, et al.
(författare)
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Flow-Integrated Preparation of Norbornadiene Precursors for Solar Thermal Energy Storage
- 2024
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Ingår i: ChemSusChem. - 1864-5631 .- 1864-564X. ; 17:2
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Tidskriftsartikel (refereegranskat)abstract
- Molecular solar thermal (MOST) energy storage systems are getting increased attention related to renewable energy storage applications. Particularly, 2,3-difunctionalized norbornadiene-quadricyclane (NBD-QC) switches bearing a nitrile (CN) group as one of the two substituents are investigated as promising MOST candidates thanks to their high energy storage densities and their red-shifted absorbance. Moreover, such NBD systems can be prepared in large quantities (a requirement for MOST-device applications) in flow through Diels-Alder reaction between cyclopentadiene and appropriately functionalized propynenitriles. However, these acetylene precursors are traditionally prepared in batch from their corresponding acetophenones using reactive chemicals potentially leading to health and physical hazards, especially when working on a several-grams scale. Here, we develop a multistep flow-chemistry route to enhance the production of these crucial precursors. Furthermore, we assess the atom economy (AE) and the E-factor showing improved green metrics compared to classical batch methods. Our results pave the way for a complete flow synthesis of NBDs with a positive impact on green chemistry aspects.
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| 2. |
- Elholm, Jacob Lynge, et al.
(författare)
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High throughput screening of norbornadiene/quadricyclane derivates for molecular solar thermal energy storage
- 2022
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 24:47, s. 28956-28964
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Tidskriftsartikel (refereegranskat)abstract
- We present a procedure for performing high throughput screening of molecular compounds for molecular solar thermal energy storage devices using extended tight binding (xTB) methods. In order to validate our approach, we performed screening of 3230 norbornadiene/quadricyclane (NBD/QC) derivatives in terms of storage energies, activation barriers and absorption of solar radiation using our approach, and compared it to high level density functional theory (DFT) and cluster perturbation (CP) theory calculations. Our comparisons show that the xTB screening framework correlates very well with DFT and CP theory in that it predicts the same relative trends in the studied parameters although the storage energies and thermal reaction barriers are significantly offset. Utilizing the screening methodology, we have been able to locate compounds that would either be excellent candidates or compounds that should not be considered further for molecular solar thermal energy storage devices. This methodology can readily be extended and applied to screening other molecular motifs for molecular solar energy storage.
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| 3. |
- Franz, Evanie, et al.
(författare)
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Tunable Energy Release in a Reversible Molecular Solar Thermal System br
- 2022
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 12:21, s. 13418-13425
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Tidskriftsartikel (refereegranskat)abstract
- Molecular solar thermal (MOST) systems open application fields for solar energy conversion as they combine conversion, storage, and release in one single molecule. For energy release, catalysts must be controllable, selective, and stable over many operation cycles. Here, we present a MOST/catalyst couple, which combines all these properties. We explore solar energy storage in a tailor-made MOST system (cyano-3-(3,4-dimethoxyphenyl)-norbornadiene/quadricyclane; NBD '/QC ') and the energy release heterogeneously catalyzed at a Au(111) surface. By photoelectrochemical infrared reflection absorption spectroscopy (PEC-IRRAS) and scanning tunneling microscopy, we show that Au triggers the energy release with very high activity. Most remarkably, the release rate of the heterogeneously catalyzed process can be tuned by applying an external potential. Our durability tests show that the MOST/catalyst system is stable over 1000 storage cycles without any decomposition. The surface structure of the catalyst is preserved, and its activity decreases by only 0.1% per storage cycle.
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| 4. |
- Ghasemi, Shima, 1993, et al.
(författare)
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Exploring the impact of select anchor groups for norbornadiene/quadricyclane single-molecule switches
- 2023
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Ingår i: Journal of Materials Chemistry C. - 2050-7534 .- 2050-7526. ; 11:44, s. 15379-15776
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Tidskriftsartikel (refereegranskat)abstract
- To achieve the ultimate limit of device miniaturization, it is necessary to have a comprehensive understanding of the structure–property relationship in functional molecular systems used in single-molecule electronics. This study reports the synthesis and characterization of a novel series of norbornadiene derivatives capped with thioether and thioester anchor groups. Utilizing the mechanically controllable break junction technique, the impact of these capping groups on conductance across single-molecule junctions is investigated. Among the selection of anchor groups, norbornadiene capped with thioacetate and tert-butyl groups exhibits higher conductance (G ≈ 4 × 10−4 G0) compared to methyl thioether (G ≈ 2 × 10−4 G0). Electronic transmission through the considered set of single-molecule junctions has been simulated. The computational results for electron transport across these junctions align closely with the experimental findings, with the thioacetate- and tert-butyl-substituted systems outperforming the methyl thioether-capped derivative. In terms of junction stability, the methyl thioether-capped system is the most resilient, maintaining consistent conductance even after approximately 10 000 cycles. Meanwhile, the likelihood of observing molecular plateaus in both the thioacetate- and tert-butyl-substituted systems declines over time. These findings substantially advance both the design and understanding of functional molecular systems in the realm of single-molecule electronics, particularly in the context of molecular photoswitches.
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| 5. |
- Ghasemi, Shima, 1993, et al.
(författare)
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Pyrene Functionalized Norbornadiene-Quadricyclane Fluorescent Photoswitches: Characterization of their Spectral Properties and Application in Imaging of Amyloid Beta Plaques
- 2024
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Ingår i: Chemistry - A European Journal. - 1521-3765 .- 0947-6539. ; 30:34
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Tidskriftsartikel (refereegranskat)abstract
- This study presents the synthesis and characterization of two fluorescent norbornadiene (NBD) photoswitches, each incorporating two conjugated pyrene units. Expanding on the limited repertoire of reported photoswitchable fluorescent NBDs, we explore their properties with a focus on applications in bioimaging of amyloid beta (Aβ) plaques. While the fluorescence emission of the NBD decreases upon photoisomerization, aligning with what has been previously reported, for the first time we observed luminescence after irradiation of the quadricyclane (QC) isomer. We deduce how the observed emission is induced by photoisomerization to the excited state of the parent isomer (NBD) which is then the emitting species. Thorough characterizations including NMR, UV-Vis, fluorescence, X-ray structural analysis and density functional theory (DFT) calculations provide a comprehensive understanding of these systems. Notably, one NBD-QC system exhibits exceptional durability. Additionally, these molecules serve as effective fluorescent stains targeting Aβ plaques in situ, with observed NBD/QC switching within the plaques. Molecular docking simulations explore NBD interactions with amyloid, unveiling novel binding modes. These insights mark a crucial advancement in the comprehension and design of future photochromic NBDs for bioimaging applications and beyond, emphasizing their potential in studying and addressing protein aggregates.
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| 6. |
- Gimenez-Gomez, Alberto, et al.
(författare)
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Cover Feature: Unveiling the Potential of Heterogeneous Catalysts for Molecular Solar Thermal Systems (Chem. Eur. J. 1/2024)
- 2024
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Ingår i: Chemistry - A European Journal. - 1521-3765 .- 0947-6539. ; 30:1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Trapping sunlight energy into chemical bonds has become an important method for storing renewable energy and releasing it on demand. To illustrate the new catalyst-testing protocol, a cyclic road shows the photoisomerization process trapping sunlight (top) and the back-conversion catalytic reaction releasing heat. The bottom wheel indicates that up to 27 different catalysts were studied. More information can be found in the Research Article by I. Funes-Ardoiz, D. Sampedro and co-workers (DOI: 10.1002/chem.202303230).
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| 7. |
- Gimenez-Gomez, Alberto, et al.
(författare)
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Unveiling the Potential of Heterogeneous Catalysts for Molecular Solar Thermal Systems
- 2024
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Ingår i: Chemistry - A European Journal. - 1521-3765 .- 0947-6539. ; 30:1
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy utilization has gained considerable attention due to its abundance and renewability. However, its intermittent nature presents a challenge in harnessing its full potential. The development of energy storing compounds capable of capturing and releasing solar energy on demand has emerged as a potential solution. These compounds undergo a photochemical transformation that results in a high-energy metastable photoisomer, which stores solar energy in the form of chemical bonds and can release it as heat when required. Such systems are referred to as MOlecular Solar Thermal (MOST)-systems. Although the photoisomerization of MOST systems has been vastly studied, its back-conversion, particularly using heterogeneous catalysts, is still underexplored and the development of effective catalysts for releasing stored energy is crucial. Herein we compare the performance of 27 heterogeneous catalysts releasing the stored energy in an efficient Norbornadiene/Quadricyclane (NBD/QC) MOST system. We report the first benchmarking of heterogeneous catalysts for a MOST system using a robust comparison method of the catalysts’ activity and monitoring the conversion using UV-Visible (UV-Vis) spectroscopy. Our findings provide insights into the development of effective catalysts for MOST systems. We anticipate that our assay will reveal the necessity of further investigation on heterogeneous catalysis.
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| 8. |
- Hillers-Bendtsen, Andreas Erbs, et al.
(författare)
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Searching the Chemical Space of Bicyclic Dienes for Molecular Solar Thermal Energy Storage Candidates
- 2023
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Ingår i: Angewandte Chemie - International Edition. - 1433-7851 .- 1521-3773. ; 62:40
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Tidskriftsartikel (refereegranskat)abstract
- Photoswitches are molecular systems that are chemically transformed subsequent to interaction with light and they find potential application in many new technologies. The design and discovery of photoswitch candidates require intricate molecular engineering of a range of properties to optimize a candidate to a specific applications, a task which can be tackled efficiently using quantum chemical screening procedures. In this paper, we perform a large scale screening of approximately half a million bicyclic diene photoswitches in the context of molecular solar thermal energy storage using ab initio quantum chemical methods. We further device an efficient strategy for scoring the systems based on their predicted solar energy conversion efficiency and elucidate potential pitfalls of this approach. Our search through the chemical space of bicyclic dienes reveals systems with unprecedented solar energy conversion efficiencies and storage densities that show promising design guidelines for next generation molecular solar thermal energy storage systems.
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| 9. |
- Hölzel, Helen, 1991, et al.
(författare)
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Probing Charge Management across the π-Systems of Nanographenes in Regioisomeric Electron Donor-Acceptor Architectures
- 2022
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 144:20, s. 8977-8986
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by light-induced processes in nature to mimic the primary events in the photosynthetic reaction centers, novel functional materials combine electron donors and acceptors, i.e., (metallo)porphyrins (ZnP) and fullerenes (C60), respectively, with emerging materials, i.e., nanographenes. We utilized hexa-peri-hexabenzocoronene (HBC) due to its versatility regarding functionalization and physicochemical properties, to construct three regioisomeric ZnP-HBC-C60 conjugates, which foster geometrical diversity by arranging ZnP and C60 in ortho-, meta-, and para-positions to each other. The corresponding hexaarylbenzene (HAB) motifs, with an interrupted π-system, were also prepared. Transient absorption measurements disclosed the fast population of charge transfer as well as singlet and triplet charge-separated states. With the help of density functional theory (DFT) calculations, we further conceive the communication across the HBCs and HABs. This work reveals the impact of both the geometrical arrangement with respect to through-space versus through-bond interactions and the structural rigidity/flexibility on the charge management across the different π-systems.
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| 10. |
- Kjaersgaard, Alexander, et al.
(författare)
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Photolytic Studies of Norbornadiene Derivatives under High-Intensity Light Conditions
- 2022
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 126:39, s. 6849-6857
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Tidskriftsartikel (refereegranskat)abstract
- The photoconversion of a norbornadiene (NBD) derivative was studied under high-intensity mono- and polychromatic light conditions at high concentrations. The photoisomerization quantum yield (φNBD→QC), proceeding from NBD to its quadricyclane (QC) isomer, was determined using a tunable OPO laser and a solar simulator light source. The solar simulator was designed to mimic the AM1.5G solar spectrum between 300 and 900 nm. Using the OPO laser, φNBD→QC was measured at discrete values between 310 and 350 nm in steps of 10 nm, and a variation between 0.81 and 0.96 was observed. Weighting these values of φNBD→QC with the spectral profile of the solar simulator, an averaged value of 0.87 ± 0.03 was obtained. Determination of φNBD→QC was also performed directly in the solar simulator providing a value of 0.97 ± 0.14, in good agreement with the weighted values from the OPO. Photoisomerization quantum yields were found to decrease slightly at higher concentrations. At high concentrations, we found that correcting for the presence of QC was important due to similar absorption coefficients of the NBD and QC isomers at the absorption tail. Cyclability of the forward and backward NBD/QC conversion was studied over several cycles. The NBD/QC couple exhibited excellent thermal stability, but a slight photodegradation per cycle was observed, increasing with the concentration of the sample. This result indicates that the molecules undergo some intermolecular reactions.
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