Schleyer Adaptation

Although the 1-adamantyl system seems ideal, the ionization of 2-adamantyl systems has become the most widely accepted system for separating the effects of ionizing power and nucleophilic assistance. Again, the reference solvent is 80% ethanol. It may not be imme- 

In summary, we have defined another tool for studying the charges that change during a mechanism. Several LFERs were discussed that give one the ability to determine both the extent of ionization at the transition state of a specific reaction and how much nucleophilic assistance has occurred, all just by changing the structure of the solvent. 

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Some of the ways in which excitai-state wavefunctions can be included in a configuration interaction Illation (Figure adapted from Hehre W ], L Roikiin, P zi R Schleyer and ] A Hehre 1986. Ab initio Molecular aital Theory. New York, Wiley.)... 

In order to apply the Jemmis-Schleyer interstitial electron rule, the closo B H 2 dianions (their isoelectronic analogues are treated similarly) are dissected conceptually into two BH caps and one or two constituent (BH) rings. The BH- caps contribute three interstitial electrons each but the rings (which, formally, have zero electrons in the n MOs), contribute none. Hence, six electrons, described as interstitial, link the bonding symmetry-adapted cap and ring orbitals together perfectly. 

The initial objective of our work was to quantify solvent effects (particularly solvent nucleophilicity) by adapting the Grunwald-Winstein equation (2) (5). In equation 2, k is the rate of solvolysis of a substrate (RX) in any solvent relative to 80% v/v ethanol-water (k0) and Y is the solvent ionizing power defined by m = 1.000 for solvolyses of tert-butyl chloride at 25 °C. In this chapter, a discussion of equation 2 and similar free-energy relationships is presented. At the time our work began (1969), in collaboration with Schleyer, mechanisms of solvolytic reactions were close to a high in controversy (6-8). More recent mechanistic developments (9-13) are not reviewed in detail here, but increased recognition of the importance of nucleophilic solvent assistance should be noted. 

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