The norbornadienedicarboxylic acid-quadricyclanedicarboxylic acid water soluble solar energy storage system

Carroll, Felix A.; Green, David K.; Sloop, Joseph C.

doi:10.1016/0038-092x(84)90170-1

Cited by 3 publications

(1 citation statement)

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“…Almost all of the MOST systems tested so far have been designed to work in organic solvents and only a very few to be used in water [34,35,[45][46][47][48][49][50], although the aqueous medium should be preferable for environmental sustainability. This is probably due to early observations of possible QC reactivity with water in the absence and in the presence of metal catalysts [45,[51][52][53], despite stable and successful MOST functioning in water also being obtained [34,35,[45][46][47][48][49][50].…”

Section: Introductionmentioning

confidence: 99%

A Norbornadiene-Based Molecular System for the Storage of Solar–Thermal Energy in an Aqueous Solution: Study of the Heat-Release Process Triggered by a Co(II)-Complex

Castro,

Gancheff,

Ramos

et al. 2023

Molecules

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It is urgent yet challenging to develop new environmentally friendly and cost-effective sources of energy. Molecular solar thermal (MOST) systems for energy capture and storage are a promising option. With this in mind, we have prepared a new water-soluble (pH > 6) norbornadiene derivative (HNBD1) whose MOST properties are reported here. HNBD1 shows a better matching to the solar spectrum compared to unmodified norbornadiene, with an onset absorbance of λonset = 364 nm. The corresponding quadricyclane photoisomer (HQC1) is quantitatively generated through the light irradiation of HNBD1. In an alkaline aqueous solution, the MOST system consists of the NBD1−/QC1− pair of deprotonated species. QC1− is very stable toward thermal back-conversion to NBD1−; it is absolutely stable at 298 K for three months and shows a marked resistance to temperature increase (half-life t½ = 587 h at 371 K). Yet, it rapidly (t½ = 11 min) releases the stored energy in the presence of the Co(II) porphyrin catalyst Co-TPPC (ΔHstorage = 65(2) kJ∙mol−1). Under the explored conditions, Co-TPPC maintains its catalytic activity for at least 200 turnovers. These results are very promising for the creation of MOST systems that work in water, a very interesting solvent for environmental sustainability, and offer a strong incentive to continue research towards this goal.

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Section: Introductionmentioning

confidence: 99%

A Norbornadiene-Based Molecular System for the Storage of Solar–Thermal Energy in an Aqueous Solution: Study of the Heat-Release Process Triggered by a Co(II)-Complex

Castro,

Gancheff,

Ramos

et al. 2023

Molecules

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Photoresponsive Carboxylic Acids

Herges

Reif²

1996

Liebigs Ann./Recl.

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A norbornadiene tetracarboxylic acid was synthesized the pKs of which can be changed by irradiation forming the quadricyclane derivative or by catalytical reisomerization to the norbornadiene. The pKs difference of both isomers in the second and fourth dissociation step is 0.59 and 0.68 units. Photochemical isomerization proceeds without decomposition at high pH (39.0). Reisomerization of the quadricyclane to the norbomadiene with a Rh' complex is also a clean reaction, but rather slow with tIl2 = 5 d at room temperature. We attribute the pH change of an aqueous solution during isomerization to the formation or cleavage of intramolecular hydrogen bonds between the adjacent carboxyl groups and accumulation or dispersion of negative charge in the quadricyclane and norbomadiene, respectively.One of the main objectives in host-guest chemistry is the design of systems whose properties can be reversibly regulated by external parameters. Of particular interest are systems that can be used as a photochemical switch [']. Biological energy conversion systems could serve as a 2,3,5,6-Tetrasubstituted norbornadienes perform a convergent grab-like or pincer movement with their four substituents on irradiation leading to the formation of the corresponding quadricyclanes. Equipped with suitable substituents these systems should allow a photochemicallcatalytical regulation of complexing properties. Using carboxylate groups it should be possible to switch the pK, values of the acid by the norbornadiene-quadricyclane isomerization (Figure 1). Compared to the azobenzene cis-trans isomerization which is used in most of the known artificial photoresponsive systems['a-'], the norbornadiene-quadricyclane isomerizati~n[~] has two major advantages: a) the photostationary equilibrium lies almost 100% on the product side and b) the reisomerization in most systems is exothermic and usually quantitative. Results SynthesisThe syntheses of 2,5-diester-, 2,3,5-triester-and 2,3,5,6-tetraester-substituted norbornadienes 2, 3 and 4 according to a Diels-Alderlretro Diels-Alder sequence was already described[4*'] (Scheme 1). Norbornadiene monoester 1 was prepared according to a literature procedurersa1. The norbornadiene esters were converted quantitatively to the corresponding quad-

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