Energy diagram cation systems

Draw an energy diagram for the three molecular orbitals of the cyclopropenyl system (C l I3). How ate these three molecular orbitals occupied in the cyclopropenyl anion, cation, and radical Which of the three substances is aromatic according to Hiickel s rule ... 

Contact and solvent-separated ion pairs can be distinguished in anionic systems the interionic distance of the former is usually 1-3 A, which increases to 4 or even 7 A in solvent-separated ion pairs [21]. There is apparently no further minimum in the potential energy diagram. The reactivity of solvent-separated ion pairs and free ions in anionic systems are similar, being a few orders of magnitude more reactive than contact ion pairs. In contrast, contact ion pairs in cationic systems are separated by 4-6 A, and therefore resemble the solvent-separated species of anionic systems in terms of structure, as well as their relative reactivity and ability to dissociate. The existence of solvent-separated ion pairs in cationic polymerization is questionable and has not yet been proven spectroscopically. 

Fig. 12 Energy diagram of photocatalytic reduction process. The conduction band (CB) and valence band (VB) for poly(DCHD) are, respectively, —3.44 tind —5.77 eV vs the vacuum level, corresponding to 1.06 and 1.27 V vs SHE. The redox potentials of [Ag(NH3)2 as a major component of the Ag cations in the present system and H2O are 0.373 and 1.23 V vs SHE, respectively...

The energy level diagram including electron populations for the allyl radical, cation, and anion can be shown as illustrated in Figure 5.16. The orbital diagram and energy levels for the allyl system is shown in Figure 5.17. 

So once again we have three p orbitals to combine. This is the same situation as before. We have the same atoms, the same orbitals, and so the same energy levels. In fact, the molecular orbital energy level diagram for this compound is almost the same as the one for the allyl cation the only difference is the number of electrons in the it system. Whereas in the allyl cation Jt system we only had two electrons, here we have three (two from the 7t bond plus the single one). Where does this extra election go Answer in tire next lowest molecular orbital—the nonbonding molecular orbital,... 

We can summarize all this information in a molecular orbital energy level diagram, the n molecular orbitals of the allyl system the allyl cation... 

From the data on divalent and tetravalent salts, a consistent picture emerges which is in perfect agreement with the Mott-Jahn-Teller insulator model of Fabrizio and Tosatti [16]. The Jahn-Teller distortion, even if dynamic, can be unambigously detected from vibrational and low-energy electronic spectra and proves that the molecular JT effect causes the nonmagnetic insulating behavior in these materials. Systems with smaller cations are on the metallic side of the UAV diagram it would be of interest to study these systems by vibrational spectroscopy as well. 

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