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Summary. Several alkylbenzene-TCNE complexes are reinvestigated, yielding improved ground state thermodynamic parameters. The effect of competing solvent complexation with the acceptor is also considered. The experimental CT-hand profiles for the complexes in solution and in the gas phase are deconvoluted into two (theoretically expected) CT-subbands, furnishing accurate energies of the first and second CT-state of thc systems. Comparison with the corresponding donor IP's leads to insight into the preferred ground state conformation oi the complexes. The thermodynamics of ionic photodissociation of the complexes is evaluated as a function of solvation and the results compared with recent experimental work.

The radical anion of (E)-azobenzene, generated from the neutral compound by reaction with potassium mirror in an ethereal solvent, bas been fully characterized by its hyperfine data with the use of ESR, ENDOR and TRIPLE resonance spectroscopy. Assignments of coupling constants to protons in the individual positions are based on comparison with the spectra of the radical anions of 4,tdideuterio and 2,t'dimethyl derivatives. Effects of "N hyperfine anisotropy on ESR spectra and of association with the counter ion K + are briefly discussed.

The radical cation of 1,3,6,8-tetraazatricyclo [4.4.1.1(3,8)]dodecane (TTD) has been studied using magnetic resonance and optical spectroscopic methods and computational techniques. With the help of deuterated isotopomers, assignments of EPR and resonance Raman spectra could be unequivocally established. The results demonstrate that the radical cation has D(2d) symmetry, and instantaneous electron delocalization over the four equivalent nitrogen atoms occurs. This extensive delocalization in a completely saturated system is a unique feature of the TTD radical cation. The spectroscopy of TTD, in contrast to that of simpler diamines such as 1,4-diaza[2.2.2]bicyclooctane, simultaneously reveals the consequences of orbital interactions through space and through bonds. The relationship between nitrogen pyramidalization and hyperfine coupling constants in nitrogen-centered radical cations with a number of different bonding arrangements is reviewed.

68.3 mmol of unreacted 1 were removed under vacuum. The residue was extracted into petroleum ether 40j60 and chromatographed several times (column and MPLC: silica gel 60 Merck/5% water; petroleum ether, toluene, THF, and binary mixtures of these solvents). Fourteen colored fractions were isolated. Five have been identified so far. namely, 3,4,5,6, and 10 (oxygen free [19b], dec. 220 C).Heating of the residue under 1 Pa to 100 "C results in complete distillation of 3 and I-methylnaphthalene. The remaining residue was subjected several times to MPLC. resulting in the isolation of several new fractions. Compound 7 (m.p. 255,'C) crystallized from a brown petroleum ether fraction. Compounds 8 and 9 precipitated as crystalline masses (no sharp melting point) within 14 d from a red-violet petroleum ether solution, the intensity of the color thereby decreasing. The crystals could be separated manually. When A1,0,/5% water was used as the stationary phase in thechromatography and the main components of the mixture were eluted. a brown residue was removed with THF from the top of the column. Concentration of this solution resulted in crystallization of partially oxidized 10. The yields of the isolated crystalline compounds 7-10 were all about 1 %. The NMR spectra of the diamagnetic speices 7-9 are very complicated and have not yet been completely analyzed. Compound 10 gives strongly broadened and paramagnetically shifted 'H NMR signals; ''C and "P NMR signals are not observable.