Effective charge maps equilibria

Scheme 1 (Chapter 3) shows that aryl acetate esters and aryl thioacetate esters have effective charges of -1-0.7 and -t-0.4 respectively on the O and S leaving atom. The effective charge map for the equilibrium can thus be written as in Scheme 3. 

The map of Bronsted p values for the cyclisation are shown in Scheme 12. The Utg for the reaction of the conjugate base is 0.55. When the reference equilibrium for the effective charge of one substituent effect is not the same as that for the other (as in Problem 12) the bonding changes can only be compared when the P or p values are normalised as Leffler indices. In the case of cyclisation to the oxazolinone it is most convenient that bond fission is measured by a Bronsted relationship and bond formation by a Hammett equation. Both p and p can be... 

The effective positive charge of the dye (qpic— 0,7) and the value of the equilibrium distance cation-anion in the PIC molecule (3 A) were determined from the quantum chemical calculation using the AMI method. The map of the calculated electrostatic potential of the PIC iodide is shown in fig. 7. 

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