83929-13-9Relevant academic research and scientific papers
Photocycloaddition of 9,10-dichloroanthracene to 1,3-Cyclohexadiene
Smothers, William K.,Meyer, Marjorie C.,Saltiel, Jack
, p. 545 - 555 (2007/10/02)
Irradiation of 9,10-dichloroanthracene (DCA) in the presence of 1,3-cyclohexadiene (CHD) gives three major adducts corresponding to addition of CHD to the 1,2-positions of DCA and addition of CHD to the 9,10- and 1,4-positions of DCA.The previously undetected adduct is the major primary photoadduct in toluene, benzene, acetonitrile, or pyridine, provided that it is protected from shorter wavelength exciting light.The dependence of emission and product quantum yields on demonstrates that interaction between the first excited singlet state of DCA with CHD is the first step of these reactions.The product distributions are not entirely consistent with a recently proposed algorithm for prediction of reactivity in allowed and photocycloadditions.DCA*CHD exciplex emission was not detected, but involvement of a singlet exciplex in the cycloadditions is suggested by (a) the inverse temperature dependence of Stern-Volmer plot slopes for CHD quenching of DCA fluorescence and (b) the marked decrease of adduct quantum yields in the presence of pyridine, a known exciplex-specific quencher.
Adiabatic S1 9,10-Dichloroanthracene Formation from Electronically Excited 9,10-Dichloroanthracene/1,3-Cyclohexadiene Photoadducts
Smothers, William K.,Saltiel, Jack
, p. 2794 - 2799 (2007/10/02)
The photochemistry and fluorescence of the two major photoadducts of 9,10-dichloroanthracene (DCA) and 1,3-cyclohexadiene (CHD) are described.The 1,2-adduct, 1,2-A (?s + 2?s> to the 1,2-positions of DCA),gives DCA and CHD as main photoproducts in several solvents, φ-1,2-A ca. φDCA ca. φCHD ca. 0.3.It exhibits fluorescence characteristic of the naphthalene moiety (350-435 nm) and, in addition, gives DCA fluorescence (390-560 nm).The pronounced oxygen quenching effect of the latter shows that cleavage of singlet excited 1,2-A, 11,2-A*, is in part adiabatic, φ1DCA* ca. 0.007-0.015.The 9,10-adduct, 9,10-A (?s + 4?s> to the 9,10-position of DCA), is efficiently destroyed by light, φ-9,10-A ca. 1.0, but gives several products in addition to DCA and CHD, φDCA ca. φCHD ca. 0.11.Its fluorescence is identical with DCA fluorescence, corresponding to φ1DCA* ca 0.0041-0.0068, depending on the solvent.The observations are discussed by using the current theoretical model for electrocyclic photochemical reactions.They suggest that if pericyclic minima are involved in adduct photocleavage and formation, they are isolated in the potential energy surface and do not readily interconvert.
