We have shown that theoretical calculations are a complementary tool to experiment in the comprehension of the behavior of such systems. In certain aspects, specially for the smaller systems, quantum chemical calculations already provide sufficiently accurate results. However, for larger molecules and time-dependent phenomena the results have not yet achieved the same level of accuracy. [Pg.21]

Based on experimental results and complementary calculations, an out-of-plane n-delocalization is suggested for thiirene dioxides . As far as the thiirene oxide is concerned, theoretical calculations predict possible spiroconjugative-type interaction between the n c=c orbital of the ring and the Jt-orbitals of the SO (which leads to aromatic stabilization and a n charge transfer backward from the SO to the C=C). There exists, however, a rather strong destabilization effect, due to the jt so(dxz)-orbital. [Pg.390]

As an example, the EPR spectrum of DPPH, one of the first radicals investigated by EPR,4-6 is not yet understood, despite its extensive study by EPR,4-16 proton NMR,15 17-22 14 broad-line NMR, 3 ENDOR,14>22,24,25 ELDOR,13 and theoretical calculations.16 26 it seems appropriate here to summarize the salient features of these studies, since they will serve as a critique of the complementary nature and limitations of the above-mentioned techniques. [Pg.324]

This is consistent with Pope s report on (Mn0H2)2(Mn)2(PWg034)2 , in which it was discovered that oxidation first occurs at the aquated Mn centers [112]. However, due to the low intensity of the observed effects and to the fact that oxidation and reduction might involve different molecular orbitals, support or invalidation for the present hypothesis should be sought through complementary theoretical calculations. [Pg.655]

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