| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- Lungerich, Dominik, et al.
(författare)
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A Singular Molecule-to-Molecule Transformation on Video: The Bottom-Up Synthesis of Fullerene C-60 from Truxene Derivative C60H30
- 2021
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 15:8, s. 12804-12814
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Tidskriftsartikel (refereegranskat)abstract
- Singular reaction events of small molecules and their dynamics remain a hardly understood territory in chemical sciences since spectroscopy relies on ensemble-averaged data, and microscopic scanning probe techniques show snapshots of frozen scenes. Herein, we report on continuous high-resolution transmission electron microscopic video imaging of the electron-beam-induced bottom-up synthesis of fullerene C-60 through cyclodehydrogenation of tailor-made truxene derivative 1 (C60H30), which was deposited on graphene as substrate. During the reaction, C60H30 transformed in a multistep process to fullerene C-60. Hereby, the precursor, metastable intermediates, and the product were identified by correlations with electron dose-corrected molecular simulations and single-molecule statistical analysis, which were substantiated with extensive density functional theory calculations. Our observations revealed that the initial cyclodehydrogenation pathway leads to thermodynamically favored intermediates through seemingly classical organic reaction mechanisms. However, dynamic interactions of the intermediates with the substrate render graphene as a non-innocent participant in the dehydrogenation process, which leads to a deviation from the classical reaction pathway. Our precise visual comprehension of the dynamic transformation implies that the outcome of electron-beam-initiated reactions can be controlled with careful molecular precursor design, which is important for the development and design of materials by electron beam lithography.
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| 8. |
- Magson, Lucien, et al.
(författare)
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Synthesis and Characterization of Carbon-Based Heterogeneous Catalysts for Energy Release of Molecular Solar Thermal Energy Storage Materials
- 2024
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Ingår i: ACS Applied Materials & Interfaces. - 1944-8252 .- 1944-8244. ; 16:6, s. 7211-7218
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Tidskriftsartikel (refereegranskat)abstract
- Molecular solar thermal energy storage (MOST) systems are rapidly becoming a feasible alternative to energy storage and net-zero carbon emission heating. MOST systems involve a single photoisomerization pair that incorporates light absorption, storage, and heat release processes in one recurring cycle. Despite significant recent advancements in the field, the catalytic back-reaction from MOST systems remains relatively unexplored. A wide range of applications is possible, contingent on the energy densities of the specific photoisomers. Here, we report platinum-, copper-, and nickel-based heterogeneous catalysts screened in batch conditions for the back-conversion reaction on the cyano-3-(4-methoxyphenyl)-norbornadiene/quadricyclane pair. Catalyst reactivities are investigated using structural characterization, imaging techniques, and spectroscopic analysis. Finally, the thermal stability is also explored for our best-performing catalysts.
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| 9. |
- Martin-Drumel, Marie-Aline, et al.
(författare)
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Searches for bridged bicyclic molecules in space-norbornadiene and its cyano derivatives
- 2023
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Ingår i: Faraday Discussions. - : Royal Society of Chemistry (RSC). - 1359-6640 .- 1364-5498. ; 245, s. 284-297
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Tidskriftsartikel (refereegranskat)abstract
- The norbornadiene (NBD) molecule, C7H8, owes its fame to its remarkable photoswitching properties that are promising for molecular solar-thermal energy storage systems. Besides this photochemical interest, NBD is a rather unreactive species within astrophysical conditions and it should exhibit high photostability, properties that might also position this molecule as an important constituent of the interstellar medium (ISM)-especially in environments that are well shielded from short-wavelength radiation, such as dense molecular clouds. It is thus conceivable that, once formed, NBD can survive in dense molecular clouds and act as a carbon sink. Following the recent interstellar detections of large hydrocarbons, including several cyano-containing ones, in the dense molecular cloud TMC-1, it is thus logical to consider searching for NBD-which presents a shallow but non-zero permanent electric dipole moment (0.06 D)-as well as for its mono- and dicyano-substituted compounds, referred to as CN-NBD and DCN-NBD, respectively. The pure rotational spectra of NBD, CN-NBD, and DCN-NBD have been measured at 300 K in the 75-110 GHz range using a chirped-pulse Fourier-transform millimetre-wave spectrometer. Of the three species, only NBD was previously studied at high resolution in the microwave domain. From the present measurements, the derived spectroscopic constants enable prediction of the spectra of all three species at various rotational temperatures (up to 300 K) in the spectral range mapped at high resolution by current radio observatories. Unsuccessful searches for these molecules were conducted toward TMC-1 using the QUIJOTE survey, carried out at the Yebes telescope, allowing derivation of the upper limits to the column densities of 1.6 x 10(14) cm(-2), 4.9 x 10(10) cm(-2), and 2.9 x 10(10) cm(-2) for NBD, CN-NBD, and DCN-NBD, respectively. Using CN-NBD and cyano-indene as proxies for the corresponding bare hydrocarbons, this indicates that-if present in TMC-1-NBD would be at least four times less abundant than indene.
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| 10. |
- Orrego Hernandez, Jessica, 1987, et al.
(författare)
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Norbornadiene/Quadricyclane (NBD/QC) and conversion of solar energy
- 2022
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Ingår i: Molecular Photoswitches: Chemistry, Properties, and Applications, 2 Volume Set. - 9783527827619 ; 1-2, s. 351-378
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter presents the norbornadiene (NBD) molecule as a photoswitch. This bicyclic molecule is photoconverted to a high-energy metastable isomer quadricyclane (QC) via light-induced [2+2] cycloaddition reaction. NBD is widely used as a molecular photoswitch due to its easily tunable isomerization properties (e.g. isomerization quantum yield, onset of absorption, half-life of the quadricyclane, and energy-storage density) by the functionalization with different chromophoric substituents. The molecular solar thermal-energy-storage system (MOST) application and its design of heat-release devices based on the NBD/QC system have been strongly evolving in the last years. However, also several new applications start to develop, making this photoswitch a versatile compound.
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