Showing papers on "Norbornadiene published in 2022"

A new approach exploiting thermally activated delayed fluorescence molecules to optimize solar thermal energy storage

Abstract: We propose a new concept exploiting thermally activated delayed fluorescence (TADF) molecules as photosensitizers, storage units and signal transducers to harness solar thermal energy. Molecular composites based on the TADF core phenoxazine-triphenyltriazine (PXZ-TRZ) anchored with norbornadiene (NBD) were synthesized, yielding compounds PZDN and PZTN with two and four NBD units, respectively. Upon visible-light excitation, energy transfer to the triplet state of NBD occurred, followed by NBD → quadricyclane (QC) conversion, which can be monitored by changes in steady-state or time-resolved spectra. The small S1-T1 energy gap was found to be advantageous in optimizing the solar excitation wavelength. Upon tuning the molecule's triplet state energy lower than that of NBD (61 kcal/mol), as achieved by another composite PZQN, the efficiency of the NBD → QC conversion decreased drastically. Upon catalysis, the reverse QC → NBD reaction occurred at room temperature, converting the stored chemical energy back to heat with excellent reversibility.

A new approach exploiting thermally activated delayed fluorescence molecules to optimize solar thermal energy storage

Abstract: We propose a new concept exploiting thermally activated delayed fluorescence (TADF) molecules as photosensitizers, storage units and signal transducers to harness solar thermal energy. Molecular composites based on the TADF core phenoxazine-triphenyltriazine (PXZ-TRZ) anchored with norbornadiene (NBD) were synthesized, yielding compounds PZDN and PZTN with two and four NBD units, respectively. Upon visible-light excitation, energy transfer to the triplet state of NBD occurred, followed by NBD → quadricyclane (QC) conversion, which can be monitored by changes in steady-state or time-resolved spectra. The small S1-T1 energy gap was found to be advantageous in optimizing the solar excitation wavelength. Upon tuning the molecule's triplet state energy lower than that of NBD (61 kcal/mol), as achieved by another composite PZQN, the efficiency of the NBD → QC conversion decreased drastically. Upon catalysis, the reverse QC → NBD reaction occurred at room temperature, converting the stored chemical energy back to heat with excellent reversibility.

MicroED characterization of a robust cationic σ-alkane complex stabilized by the [B(3,5-(SF5)2C6H3)4]− anion, via on-grid solid/gas single-crystal to single-crystal reactivity

Abstract: Microcrystalline (∼1 μm) [Rh(Cy2PCH2CH2PCy2)(norbornadiene)][S-BArF4], [S-BArF4] = [B(3,5-(SF5)2C6H3)4]−, reacts with H2 in a single-crystal to single-crystal transformation to form the σ-alkane complex [Rh(Cy2PCH2CH2PCy2)(norbornane)][S-BArF4], for which the structure was determined by microcrystal Electron Diffraction (microED), to 0.95 Å resolution, via an on-grid hydrogenation, and a complementary single-crystal X-ray diffraction study on larger, but challenging to isolate, crystals. Comparison with the [BArF4]− analogue [ArF = 3,5-(CF3)2(C6H3)] shows that the [S-BArF4]− anion makes the σ-alkane complex robust towards decomposition both thermally and when suspended in pentane. Subsequent reactivity with dissolved ethene in a pentane slurry, forms [Rh(Cy2PCH2CH2PCy2)(ethene)2][S-BArF4], and the catalytic dimerisation/isomerisation of ethene to 2-butenes. The increased stability of [S-BArF4]− salts is identified as being due to increased non-covalent interactions in the lattice, resulting in a solid-state molecular organometallic material with desirable stability characteristics.

Long‐Term Energy Storage Systems Based on the Dihydroazulene/Vinylheptafulvene Photo‐/Thermo‐switch

Abstract: The dihydroazulene/vinylheptafulvene (DHA/VHF) couple presents a photo-/thermo-switch that has attracted interest for the development of molecular solar thermal energy storage systems. Here we present the synthesis and optical as well as switching properties of DHA derivatives incorporating alkyne and norbornadiene (NBD) substituents at position C2. The corresponding VHF isomers exhibited remarkably long lifetimes. Thus, the VHF-to-DHA back-reaction half-life for a derivative with a phenylethynyl substituent was 22 days in acetonitrile at room temperature, while the half-life of a VHF reference compound having a phenyl substituent is around 3.5 h under the same conditions. This finding is particularly attractive in the quest for long-term energy storage systems, considering limited enhancement of molecular weight and maintenance of good quantum yield photoisomerization. Moreover, from the thermal back-reaction of an NBD compound, used as a precursor for the DHA-NBD dyad, we estimated the radical-stabilizing influence of a C(Me)=C(CN) 2 substituent.

Prospects of Improving Molecular Solar Energy Storage of the Norbornadiene/Quadricyclane System through Bridgehead Modifications.

Abstract: We have investigated novel bicyclic diene molecular solar thermal energy storage systems that presently are the ones with the highest predicted energy density. Using a variety of different ab initio quantum chemical methods, we report storage energies, absorption spectra, and reaction barriers for the release of stored energy for a series of bicyclic dienes. The bicyclic dienes are all constructed by modifying the bridgehead of the well-known norbornadiene/quadricyclane (NBD/QC) system. In conclusion, we find it promising that it is possible to significantly amplify the storage energy of the NBD/QC system without seriously compromising other crucial properties by introducing simple modifications to the bridgehead.

Heterogeneously supported active Pd(0) complex on silica mediated by PEG as efficient dimerization catalyst for the production of high energy density fuel

Abstract: High energy-density hydrocarbon fuels are the key materials for aircraft to increase payload and expand flight distance. Under the catalysis of atomically dispersed Pd(0) complex, saturated hexacyclic exo-exo product with good fuel property can be synthesized via co-dimerization of norbornadiene (NBD) with quadricyclane (QC). But the fragile coordination state of homogeneous Pd(0) complex limited its application in fuel production. In this work, Pd(0) complex has been heterogeneously supported on silica support with the regulation of polyethylene glycol (PEG) to increase its stability and recyclability with limited sacrifice of the activity and dimer selectivity. The structure of silica support was tuned to achieve the proper interaction with PEG and Pd(0) complex. The chain length and concentration of PEG were adjusted to further optimize the state of Pd(0) complex on silica. The as-developed heterogeneous Pd(0) complex supported on dendritic mesoporous silica nanospheres regulated by PEG2000 exhibited superior performance for the production of high energy density fuel through selective NBD-QC co-dimerization.

Optimization of the thermochemical properties of the norbornadiene/quadricyclane photochromic couple for solar energy storage using nanoparticles.

Abstract: In this paper, we present an investigation concerning the prospects of using nanoparticles to improve solar energy storage properties of three different norbornadiene/quadricyclane derivatives. Computationally, we study how different nanoparticles influence the properties of the systems that relate to the storage of solar energy, namely, the storage energy and the back reaction barrier. Our approach employs hybrid quantum mechanical/molecular mechanical calculations in which the molecular systems are described using density functional theory while the nanoparticles are described using molecular mechanics. The interactions between the two subsystems are determined using polarization dynamics. The results show that the influence of the nanoparticles on the thermochemical properties largely depends on the type of nanoparticle used, the relative orientation with respect to the nanoparticle, and the distance between the the nanoparticle and the molecular system. Additionally, we find indications that copper and/or titanium dioxide nanoparticles can lower the energy barrier of the back reaction for all of the studied systems without significantly lowering the storage capability of the systems. Consequently, the study shows that nanoparticles can potentially be employed in the optimization of molecular photoswitches towards solar energy storage.

Surface Chemistry of the Molecular Solar Thermal Energy Storage System 2,3‐Dicyano‐Norbornadiene/Quadricyclane on Ni(111)

Abstract: Abstract Molecular solar thermal (MOST) systems are a promising approach for the introduction of sustainable energy storage solutions. We investigated the feasibility of the dicyano‐substituted norbornadiene/quadricyclane molecule pair on Ni(111) for catalytic model studies. This derivatization is known to lead to a desired bathochromic shift of the absorption maximum of the parent compound. In our experiments further favorable properties were found: At low temperatures, both molecules adsorb intact without any dissociation. In situ temperature‐programmed HR‐XPS experiments reveal the conversion of (CN)2‐quadricyclane to (CN)2‐norbornadiene under energy release between 175 and 260 K. The absence of other surface species due to side reactions indicates full isomerization. Further heating leads to the decomposition of the molecular framework into smaller carbonaceous fragments above 290 K and finally to amorphous structures, carbide and nitride above 400 K. DFT calculations gave insights into the adsorption geometries. (CN)2‐norbornadiene is expected to interact stronger with the surface, with flat configurations being favorable. (CN)2‐quadricyclane exhibits smaller adsorption energies with negligible differences for flat and side‐on geometries. Simulated XP spectra are in good agreement with experimental findings further supporting the specific spectroscopic fingerprints for both valence isomers.

Electrocatalytic Energy Release of Norbornadiene‐Based Molecular Solar Thermal Systems: Tuning the Electrochemical Stability by Molecular Design

Abstract: Abstract Molecular solar thermal (MOST) systems, such as the norbornadiene/quadricyclane (NBD/QC) couple, combine solar energy conversion, storage, and release in a simple one‐photon one‐molecule process. Triggering the energy release electrochemically enables high control of the process, high selectivity, and reversibility. In this work, the influence of the molecular design of the MOST couple on the electrochemically triggered back‐conversion reaction was addressed for the first time. The MOST systems phenyl‐ethyl ester‐NBD/QC (NBD1/QC1) and p‐methoxyphenyl‐ethyl ester‐NBD/QC (NBD2/QC2) were investigated by in‐situ photoelectrochemical infrared spectroscopy, voltammetry, and density functional theory modelling. For QC1, partial decomposition (40 %) was observed upon back‐conversion and along with a voltammetric peak at 0.6 Vfc, which was assigned primarily to decomposition. The back‐conversion of QC2, however, occurred without detectable side products, and the corresponding peak at 0.45 Vfc was weaker by a factor of 10. It was concluded that the electrochemical stability of a NBD/QC couple is easy tunable by simple structural changes. Furthermore, the charge input and, therefore, the current for the electrochemically triggered energy release is very low, which ensures a high overall efficiency of the MOST system.

Design of Improved Molecular Solar‐Thermal Systems by Mechanochemistry: The Case of Azobenzene

Abstract: Molecular solar‐thermal systems (MOST) have emerged in these last years as a novel concept to store solar light. They rely on two state molecular switches that can absorb a photon to convert the initial state A to a higher‐in‐energy state B. The chemical energy stored by B can be then released to reconstitute A. Although simple in its principle, an optimal MOST needs to satisfy several requirements: incoming photon energy in the solar spectrum range, high photoreaction quantum yield, high storage density, no degradation. The first challenge is therefore the search for molecular switches that accomplish all such properties. Until now, trial‐and‐error experiments have been performed, led by physicochemical intuition. The result is that most of the initially proposed switches have been abandoned in favor of the preferred norbornadiene/quadricyclane system, together with its derivatives. Nevertheless, most of the solar spectrum is still out of the MOST absorption region, hence requiring novel approaches. Here, it is shown how mechanochemistry can be applied to improve the principally desired characteristics of a MOST: photon absorption energy, storage energy, and thermal B‐to‐A energy barrier. It is especially shown how azobenzene—a paradigmatic photoswitch still attracting much attention—can be proposed, within certain limits, as a MOST when applying external forces.

Norbornadiene/Quadricyclane ( <scp>NBD</scp> / <scp>QC</scp> ) and Conversion of Solar Energy

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.

High throughput screening of norbornadiene/quadricyclane derivates for molecular solar thermal energy storage.

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.

Tunable Energy Release in a Reversible Molecular Solar Thermal System

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.

Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions

Abstract: The photochromic norbornadiene/quadricyclane system is among the most promising candidates for molecular solar thermal (MOST) energy storage. As in this context there is still the need for new tailor-made derivatives, borylated norbornadienes were synthesized that may be used as versatile building blocks. Thus, the 4,4,5,5-tetramethyl-2-(bicyclo[2.2.1]heptadien-2-yl)-1,3,2-dioxaborolane was prepared and shown to be a suitable substrate for Pd-catalyzed Suzuki–Miyaura coupling reactions with selected haloarenes. It was demonstrated exemplarily that the novel monosubstituted 2-(1-naphthyl)norbornadiene, that is accessible through this route, is transformed to the corresponding quadricyclane upon irradiation, whereas the back reaction can be accomplished by thermal treatment.

Star-shaped Pd(II) and Pt(II) complexes containing C3-symmetric conjugated thiophenes: Synthesis, characterization, and chemical reactions with organic unsaturated molecules

Abstract: Abstract Triple oxidative addition reactions of [M0(styrene)(PMe3)2] (M = Pd/Pt) with C3-symmetric star-shaped molecules containing 1-, 3-, and 5-thiophene-substituted benzene, in 1:0.3 ratio, afforded new Pd(II) and Pt(II) trinuclear complexes in suitable yields. Analogous trinuclear complexes were formed by similar reactions of thiophenyl halide derivatives containing triazine or triphenylamine cores. Alternatively, a trinuclear Pd(II) complex was obtained by oxidative addition of a Pd(0) complex (synthesized from allyl(cyclopentadienyl) palladium(II), [(η5-C5H5)Pd(η3-C3H5)] with PEt3. Sonogashira-type coupling between trinuclear Pt(II) halides (containing C3-symmetric conjugated thiophenes) and alkynes, in the presence of cuprous halide and diethylamine, afforded alkynyl-containing trinuclear Pt(II) complexes with extended π-conjugation. Insertion reactions of organic isocyanides (CN-R) with trinuclear Pd(II) complexes yielded trinuclear Pd(II) imidoyl complexes by insertion of CN-R into Pd-carbon (thiophene) bonds. Reactions of trinuclear Pt(II) halides with Ag(OCOCF3) and NaN3 formed pseudohalogen-containing Pt(II) complexes. Graphical Abstract

Polymerization of Diazoacetates Initiated by the Pd(N-arylmaleimide)/NaBPh4 System: Maleimide Insertion into a Pd–C Bond Preceding to Initiation Leading to Efficient α-Chain-End Functionalization of Poly(alkoxycarbonylmethylene)s

Abstract: Three new N-arylmaleimide-based Pd(0) complexes [Pd(N-phenylmaleimide)2(2,5-norbornadiene) (1), Pd(N-2,6-difluorophenylmaleimide)2(2,5-norbornadiene) (2), and Pd(N-2,6-difluorophenylmaleimide)2(dibenzylideneacetone) (3)] were prepared and used as an initiator in conjunction with NaBPh4 [Pd(N-arylmaleimide)/NaBPh4 system] for polymerization of diazoacetates. The Pd(N-arylmaleimide)/NaBPh4 system polymerized a series of diazoacetates (ethyl, benzyl, and cyclohexyl diazoacetates) to yield polymers in moderate to good yield, particularly showing a high activity for cyclohexyl diazoacetate. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis and other experimental observations revealed the incorporation of one N-arylmaleimide molecule coordinated on the Pd center into the α-chain end of the polymers obtained with the initiating system, indicating that the initiating species of the polymerization was generated by insertion of N-arylmaleimide into a Pd–Ph linkage, which was first formed by the reaction of the Pd(0) complex with NaBPh4, and that the initiating system would enable syntheses of α-chain-end-functionalized poly(alkoxycarbonylmethylene)s.

Photolytic Studies of Norbornadiene Derivatives under High-Intensity Light Conditions.

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.

Features of heterogeneous catalytic transformations of strained carbocyclic compounds of the norbornene series

Abstract: Objectives. Catalytic processes involving norbornene (NBN) and norbornadiene (NBD) offer exceptional opportunities for the synthesis of a wide range of hard-to-reach polycyclic hydrocarbons. The problems of selectivity and manufacturability of these reactions are fundamentally important for their practical implementation. The aim of this review is to summarize the latest advances in the field of designing heterogeneous catalysts for the preparation and transformation of promising NBN- and NBD-derivatives with the maintenance of a strained carbocyclic framework in isomerization and dimerization reactions of these compounds.Results. Various strategies for the selection of catalysts and prospects for the development of heterogeneous catalysis for syntheses based on NBN and NBD derivatives were considered. The possibility of selective cyclic dimerization and isomerization of NBN and NBD was shown. The factors that affect the direction of the reactions and make it possible to maintain the strained norbornane structure were discussed.Conclusions. An analysis of the current state of this problem showed that at present, the technological parameters of the conversion of NBD and NBN derivatives with the participation of heterogeneous catalysts are significantly inferior to homogeneous systems. In order to improve the productivity of these processes and design catalyst regeneration, further investigations are required. However, some progress in these areas has already been made. In a number of processes, it is possible not only to maintain the strained carbocyclic framework, but also to establish ways to control regio- and stereo-selectivity. In some cases, the use of heterogeneous catalysts allows the process to be direct into a completely new path, which has no analogues for homogeneous systems.

Reversible Photoinduced Conversion of Unprecedented Norbornadiene‐Based Photoswitches with Redox‐Active Naphthalene Diimide Functionalities

Abstract: Abstract An unprecedented compound class of functional organic hybrids consisting of a photoswitchable norbornadiene building block and a redoxactive chromophore, namely naphthalene diimide, were designed and synthesized. Within these structures the capability of rylene chromophores to function as a redox active catalyst upon their photoexcitation was utilized to initiate the oxidative back‐conversion of the in situ formed quadricyclane unit to its norbornadiene analogue. In this way successive photoexcitation at two different wavelengths enabled a controlled photoswitching between the two isomerical states of the hybrids. Beyond this prove of concept, the dependency of the reaction rate to the intramolecular distance of the two functional molecular building blocks as well as the concentration of the photoexcited sample was monitored. The experimental findings and interpretations were furthermore supported by quantum chemical investigations.

Norbornadieno: síntese e aplicações

Abstract: NORBORNADIENE: SYNTHESIS AND APPLICATIONS. Bicyclo[2.2.1]hepta-2,5-diene or norbornadiene (NBD) is a bicyclic hydrocarbon molecule used in many fields of chemistry since its first synthesis in 1950. NBD is the precursor of Aldrin, an agrochemical that was commonly used as an insecticide until the end of the XX century. Norbornadiene is capable of interconverting into its isomer, quadricyclane (QC), by the incidence of ultraviolet light. After that, the QC can release heat to return to the initial stage of NBD. To increase the energy efficiency and to enable the reaction to occur at the solar light, chemists have synthesized a wide variety of NBD derivatives. Papers in more than seventy years have studied and reported the physical and chemical properties of those compounds and their applications as rocket fuel, solar energy cell, homogeneous catalysis, and agrochemicals published between 1950 and 2021. Even computational chemistry has been used to investigate the NBD derivatives synthetic routes, elucidation, and application. In addition, this review describes other applications of norbornadiene.

An Alternative to Norbornene: Unstrained Alkene Ligands with a Coordination Site for Catellani Reactions

Abstract: Key words alkene ligands - Catellani reaction - dithiane - palladium catalysis

Multiconfigurational calculations and photodynamics describe norbornadiene photochemistry

Abstract: Storing solar energy is a vital component of using renewable energy sources to meet the growing demands of the global energy economy. Molecular solar thermal (MOST) energy storage is a promising means to store solar energy with on-demand energy release. The light-induced isomerization reaction of norbornadiene (NBD) to quadricyclane (QC) is of great interest because of the generally high energy storage density (0.97 MJᐧkg–1) and long thermal reversion lifetime (t1/2, 300K = 8346 years). However, the mechanistic details of the ultrafast excited-state [2+2]-cycloaddition is largely unknown due to the limitations of experimental techniques in resolving accurate excited-state molecular structures. We now present a full computational study on the excited-state deactivation mechanism of NBD in the gas phase. Our multiconfigurational calculations [SA6-CASSCF(4,7)/ANO-S-VDZP] and non-adiabatic molecular dynamics simulations have enumerated the possible pathways with 600 S2 initial conditions for 300 fs. The predicted S2 and S1 lifetimes are reported (62 and 221 fs). The QC: NBD formation ratio is 1:5; the predicted quantum yield of QC is 9%, which underscores the potential of NBD for MOST materials. Our simulations also show the mechanisms of forming other possible reaction products and their quantum yields.

A Photochemical Overview of Molecular Solar Thermal Energy Storage

Abstract: The design of molecular solar fuels is challenging because of the long list of requirements these molecules have to fulfil: storage density, solar harvesting capacity, robustness, and heat release ability. All of these features cause a paradoxical design due to the conflicting effects found when trying to improve any of these properties. In this contribution, we will review different types of compounds previously suggested for this application. Each of them present several advantages and disadvantages, and the scientific community is still struggling to find the ideal candidate suitable for practical applications. The most promising results have been found using norbornadiene-based systems, although the use of other alternatives like azobenzene or dihydroazulene cannot be discarded. In this review, we primarily focus on highlighting the optical and photochemical aspects of these three families, discussing the recently proposed systems and recent advances in the field.

Reversible Photoisomerization of Norbornadiene‐Quadricyclane within a Confined Capsule†

Abstract: With the desire to develop a sustainable green method to store and release solar energy via a chemical reaction, we have examined the well‐investigated norbornadiene‐quadricyclane (NBD‐QC) system in water. In this context, we have employed octa acid (OA) as the host that forms a capsule in water. According to 1H NMR spectra and diffusion constants, OA forms a stable 2:2 complex with both NBD and QC and 1:1:2 mixed complex in the presence of equal amounts of both NBD and QC. The photoconversion of NBD to QC within the OA capsule is clean without side reactions. In this case, OA itself acts as a triplet sensitizer. Recognizing the disadvantage of this supramolecular approach, in the future we plan to look for visible light absorbing sensitizers to perform this conversion. The reverse reaction (QC to NBD) is achieved via electron transfer process with methylene blue as the sensitizer. This reverse reaction is also clean, and no side products were detected. The preliminary results reported here provide “proof of principle” for combining green, sustainable and supramolecular chemistries in the context of solar energy capture and release.