Aza-bicyclooctadiene/tetracyclooctane couples as promising photoswitches for molecular solar thermal energy storage applications

Abstract

The scrutiny of molecular photoswitches has received utmost attention owing to their plethora of promising applications. Bicyclooctadiene/Tetracyclooctane (BOD/TCO) couple is recently recognized as a suitable photoswitching system for molecular solar...

Aza-bicyclodiene based photoswitches for molecular solar thermal energy storage

“…This infers that the effect on Δ G str is only marginal if the bridgehead and closest unsaturated C of bicyclodiene are replaced by N. The observed trend of variation in storage energy with position of N in bicyclodiene-based photoswitches with different bridge lengths resembles that of the NBD/QC system and the recently reported BOD/TCO system. 59 This indicates that the position of N is crucial for modulating the storage energy in bicyclodiene-based photoswitches with different bridge lengths. Notably, the presence of N in the unsaturated position improves the storage energy, whereas replacing the bridgehead C with N may degrade the energy storage properties in the studied bicyclodiene based photoswitches.…”

“…A recently reported BOD/TCO couple displayed a decrease in DG str of 19.42 and 39.12 kJ mol À1 for the same bridgehead N-substituted systems. 59 However, the reductions in DG str in the BND/TCN, ABND/ATCN, and OBND/OTCN photoswitches are only 11.24 to 12.90 kJ mol À1 for the IIa and 25.71 to 29.88 kJ mol À1 for the Va systems. DG str is decreased by only 0.23 kJ mol À1 for the IIa-OBDD/OTCD couple.…”

“…58 In aza-bicyclodiene switches, N may internally involve a push-pull mechanism and the properties can be tuned without reducing the energy storage density due to the mass of N, and thus is advantageous over bulky group substituents. 59 Thermal back reaction barrier (DE TBR ). A larger thermal back reaction barrier (DE TBR ) is essential to extend the lifespan of the metastable photoisomer and store solar energy as chemical energy for a longer period.…”

“…More recently, the influence of N-substitution on the properties of a BOD/TCO photoswitch has been reported, however there is no clue for the effect of N-substitution with the different bridge lengths. 59 In the present investigation, ring strain in various bicyclic diene photoswitching systems with different bridge lengths were quantified. Further, the impacts of ring strain on the thermochemical properties are discussed to assist future MOST system designing and engineering.…”

“…More recently, the influence of N -substitution on the properties of a BOD/TCO photoswitch has been reported, however there is no clue for the effect of N -substitution with the different bridge lengths. 59…”