Azines excitation energies

Calculated and Observed Carbon-13 Chemical Shifts in Azines, Jaffe and Bene CNDO-MO s, Average Excitation Energy (AEE) and Different Excitation Energy... 

Further, a systematic study of energy characteristics in a series of azines containing 2-4 nitrogen atoms in the molecule and of dihydro-azines has been published.29,30 A correlation was found between the calculated quantities and the experimental electronic excitation energies as well as the stabilities. Molecular diagrams were calculated for a selected group of representatives. Quite recently, various HMO and SCF characteristics have been calculated for a series of pyridinelike heterocycles and their amino derivatives.31... 

Similarly, the fluorescence intensity of the 1,4-disubstituted azine with ferrocene and pyrene units (17) can be reversibly modulated by sequential redox reactions of ferrocene moiety. In the neutral state, compound 17 displays weak fluorescence owing to the electron transfer from the ferrocenyl group to the excited pyrene unit or by energy transfer from the excited pyrene unit to the ferrocenyl unit. Oxidation of the ferrocenyl unit, however, leads to remarkable fluorescence enhancement. This is because the ferrocenium cation shows weak electron donating ability and also the corresponding spectral overlap becomes small.27... 

The absorption and fluorescence spectra of azulene (1) and cycl[3.3.3]azine (2) are shown in Figures 4.22 and 4.23. The fluorescence emissions are from the second excited singlet state S2, in violation of Kasha s rule (Section 2.1.8), due to the large energy gap between the Si and S2 states in these compounds. 

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