The Azoalkane 7,8-Benzo-2,3-diazatricyclo4,9>nona-2,7-diene as Spin State Specific Chemical Titrant of Singlet and Triplet Excitation Generated in the Thermolysis of Dioxetanes

Article abstract of DOI:10.1021/ja00342a006

A convenient and sensitive analytical method for the chemical titration of chemienergized singlet excited carbonyl products generated in the thermal decomposition of 1,2-dioxetanes is described.This novel method engages the spin state specific photodenitrogenation of the azoalkane 7,8-benzo-2,3-diazatricyclo<4.3.0.0^4,9>nona-2,7-diene into 2,3-benzotricyclo<3.2.0.0^4,6>hept-2-ene (BTH) as chemical titrant, using capillary gas chromatography (CGC) in the quantitation of BTH.Provided the singlet energy of the chemienergized carbonyl product is greater than 79 kcal/mol, the present method allows the determination of singlet excitation yields (θ^S) as low as 0.05percent within an error margin of ca. 15percent.Furthermore, it is shown that the triplet spin state specific photorearrangement of the azoalkane BDT into 7,8-benzo-2,3-diazatricyclo<4.3.0.0^2,9>nona-3,7-diene might be a potentially useful method for the chemical titration of triplet carbonyl products chemienergized in the thermolysis of 1,2-dioxetanes.