Proton transfer between chemically different acceptor

V. Proton Transfer between Chemically Different Acceptor Sites, 183... 

PROTON TRANSFER BETWEEN CHEMICALLY DIFFERENT ACCEPTOR SITES 183... 

When this conjugation occurs, the level of active (corrosive) acid is substantially decreased. No simple quantitive correlation has been shown between the acidity (pKa) of acids in hydrocarbon formulation and low polar solvents (Coetzee, 1967). Acid-base interaction with and without proton transfer (PT) (BH+A B...(HA)m) has been related to acid and base enthalpies of reaction (Pawlak and Bates, 1982), the infrared carbonyl stretching band and gradual appearance of the asymmetric COO band (Lindeman and Zundel, 1972 Magonski and Pawlak, 1982), changes in pH (Kuna et al., 1982 Pawlak et al., 1982), NMR proton chemical shifts (Magonski and Pawlak, 1982), and dipole moments (Sobczyk and Pawelka, 1979). These parameters depend upon the acid-base strength of the partners, ApKa(PT) the difference between the pKa(acceptor) and pKa(donor) on the water scale (Sobczyk, 2001). 

Charge transfer forces involve the movement of electrons or protons from one molecule to another. Electron pair donor - electron pair acceptor complexes (EPD-EPA) result from the donation of a pair of electrons giving rise to electrostatic attraction between two charged species. The difference between this type of bond and a normal chemical bond is that both bonding electrons are derived from the same molecule (the EPD), the role of the EPA being to provide an empty orbital. It is important not to confuse the EPD-EPA complex with ion pair formation resulting from proton transfer [34],... 

Acidic/Basic Lewis acidity/basicity determines the solvent s ability to donate or accept a pair of electrons to form a coordinate bond with solute and/or between solvent molecules. A scale for this acid/base property was proposed by Gutman (DN and AN donor and acceptor number, respectively) based on calorimetric determination. The complete proton transfer reaction with formation of protonated ions is determined by proton affinity, gas phase acidity, acid or base dissociation constants. Both concepts differ in terms of net chemical reaction. Acidity functions are not unique properties of the solvent system alone, but depend on the solute (or family of closely related solutes) with respect to which the thermodynamic tendency is measured. ... 

---