“The photoaromatization of some substituted bicyclooctadiene derivatives”

Synthesis, characterization and computational evaluation of bicyclooctadienes towards molecular solar thermal energy storage

“…Upon irradiation, BODs can be converted to the corresponding photoisomer tetracyclooctane (TCO) (7). [15][16][17][18] The photophysical properties of BODs have been much less explored than other systems, one reason being that the photoisomer, TCO, is rapidly converted to BOD through thermal activation. Also, upon heating, BODs can degrade into an aromatic byproduct via a retro-Diels-Alder process and since the gaseous ethene is lost during the process, the reaction is irreversible (Scheme 1).…”

“…This degradation has also been seen under photochemical conditions . 15 However, several examples of BODs and the corresponding TCOs have been isolated and reported in the literature . [15][16][17][18] For example, Gleiter et.al 19 described the formation of TCOs (Figure 2).…”

“…15 However, several examples of BODs and the corresponding TCOs have been isolated and reported in the literature . [15][16][17][18] For example, Gleiter et.al 19 described the formation of TCOs (Figure 2). The methyl estersubstituted (8) could not be isolated but proven by trapping with HCl, while 9 containing an epoxide functionality, could be isolated at 0 o C. TCO (10), with trifluoromethyl groups, was found to be more stable, with a half-life of 5.5 minutes at 80 o C. 19…”

“…Upon irradiation, BODs can be converted to the corresponding photoisomer tetracyclooctane (TCO) (7). 15–18 …”

Investigation of the Structural and Thermochemical Properties of [2.2.2]-Bicyclooctadiene Photoswitches

“…The photophysical properties of BODs and their corresponding photoisomer tetracyclooctane (TCO) have been much less explored than NBDs, and the system has, to the best of our knowledge, never been considered as a candidate for storage of solar energy. The reason is most likely that the final TCO is short-lived and irradiation of BODs can, instead of the desired [2 + 2] photoisomerization reaction, lead to defragmentation to an aromatic biproduct along with ethene formation through a retro-Diels–Alder reaction. − Despite that, TCOs have been isolated through irradiation of BODs, and in 1996, Gleiter and Ohlbach isolated a variety of TCOs that are shown in Figure . TCO with the methyl ester groups (1) could not be isolated but proven by trapping with HCl.…”