It is well-known that when polycyclic aromatic hydrocarbons (PAHs) in solution are irradiated by light with their absorption wavelength, they react with molecular oxygen dissolved in solvent to form endo-peroxides. This photooxygenation occurs due to 1,4cycloaddition of singlet oxygen to a PAH molecule in the ground state. When rubrene in benzene solution was irradiated by light, the color of solution gradually changed from reddish orange to colorless. The rubrene peroxide was crystallized from 1,4-dioxane solution and X-ray structure analysis was carrid out. A molecular oxygen bonds to 5 and 12 carbon pair of the naphthacene skeleton. Although the naphthacene moiety of rubrene has completely planar structure due to the crystallographic symmetry, that of the peroxide is largely bent at the positions where molecular oxygen binds. The structure optimization of PAHs including rubrene and their peroxide was performed by applying semi-empirical molecular orbital calculation methods. The optimized structure was coincident with the experimentally determined structure. The photooxygenation reactivity of PAHs including rubrene was well explained by the differences in heats of formation between PAHs and their peroxide.
C 4 H 16 Cl 2 MnN 8 S 4 ,tetragonal, P4 2 /n (no. 86), a =13.7526(9) Å, c =9.Source of material Thiourea (SC(NH 2 ) 2 )a nd manganese chloride tetrahydrate (MnCl 2 ×4H 2 O) with the molar ratio of 1:1 are the starting material, 5mmolMnCl 2 ×4H 2 Oisfirst dissolved in 50 ml water solvent. Then, the samemole amount of SC(NH 2 ) 2 is added slowly, and the mixture is well stirred at room temperature for about 1huntil the raw materials are dissolved. The super-saturated solution is kept at elevated temperaturevia awater bath,and then the white, transparentand irregularcrystalsare formed graduallyduringthe continuouse vaporationp rocess.T he size of theg rown single crystals is tightlyr elated to theg rowing temperatures, and the largest single crystal with size of 5´2´1.5 mm 3 is obtained under the50°Cwater bath after twoweeks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.