Excitation energies five states, derivation

When using the symmetry rules for the integrals of degenerate MOs, the excitation energies for the five states, i.e Au, Ta, T2u, Gu, and Hu, are derived as... 

It is not always easy to ascertain if the addition reaction proceeds via the triplet excited state of the arene. Benzene and its simple derivatives such as anisole and benzonitrile have high triplet energies (benzene, 84 kcal/mol 1 anisole, 81 kcal/mol" benzonitrile, 77 kcal/mol-1) which makes sensitization impracticable. Results of quenching experiments are sometimes difficult to interpret, as has become evident from the work of Cantrell. He found [109] that the formation of adducts from benzonitrile and 2,3-dimethylbut-2-ene, vinyl acetate, and 2-methoxypropene in solutions 0.5 M in cri-l,3-pentadiene occurs at a rate only approximately one-fourth that in the absence of added quencher. Five years later, the author reported [110] that m-l,3-pentadicnc itself adds slowly to benzonitrile to give ortho adducts. When a correction was made for the reaction of benzonitrile with the quencher, it became apparent that little, if any, triplet quenching had occurred. 

For a series of carbonyl systems, one of which was a benzodifuran derivative (2), the energies of the first five singlet and triplet excited states were calculated by CNDO/S-CI methods. For compound (2), three quasi degenerate low-lying mr states were proposed, and the effects of NH2, OH, and CN substituents were determined <85ZN(A)859>. 

The electrogenerated chemiluminescence (ECl) of five l-amino-3-anthryl-9-propane derivatives has been studied in tetrahydrofuran. Emission from intramolecular exciplexes in ECl spectra and weak emission from the locally excited anthracene moiety were observed. The influence of triplet state interaction in ECl emission is discussed. The chemiluminescent decomposition of three a-peroxy-lactones gives CO2 and the corresponding ketone in high yield. The chemiluminescent species produced has been investigated in some detail by measurements of lifetime, energy-transfer activation parameters, and photochemical reactions. 

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