Gutmann Approach

The Gutmann approach was to allocate a donor number (DN) for bases, and an acceptor number (AN) for acids, corresponding to the definitions first proposed by Lewis. The DN was determined by measuring in a calorimeter the heat of reaction between the base under investigation and antimony pentachloride in a dilute 1,2 dichloroethane solution. The AN was determined from the P NMR shift of triethylphosphine oxide (TEPO) when dissolved in the acid under investigation. The number allocated was determined from a linear scale in which -hexane was designated as zero and antimony pentachloride was designated as 100. 

Gutmann then proposed that the heat of reaction between acids and bases (AH, ) could be calculated using Equation (3.1)  

AHgb is the enthalpy of reaction between an acidic species A, and a basic species B. and Cg are the covalent constants for the acid and base, respectively, and E and Eg are the electrostatic constants for the acid and base. This approach is also not without limitation as it assumes that the two interacting species are purely acidic or basic, and does not take into account any interactions due to acid sites on the basic species, or basic sites on the acid. 

The most significant work to use acid-base theory to understand the surface chemistry of inorganic fillers has been carried out by Fowkes and his co-workers [1-4, 10-12]. 

They made use of the Drago Equation (3.2) to characterise a series of particulate inorganic materials, e.g., ferric oxide, silica and titania, and ascribed E and C constants to their surfaces. 

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Gutmann, V., The Donor-Acceptor Approach to Molecular Interactions. Plenum Press, New York, 1978. 

Application of the functional approach to bond variations under pressure. V. Gutmann and H. Mayer, Struct. Bonding (Berlin), 1976, 31, 50-66 (58). 

Phenomenological approach to cation-solvent interactions. U. Mayer and V. Gutmann, Struct. Bonding (Berlin), 1972,12,113-140 (102). 

Gutmann V, Mayer H (1976) Application of the Functional Approach to Bond Variations Under Pressure. 31 49-66... 

Mayer U, Gutmann V (1972) Phenomenological Approach of Cation-Solvent Interactions. 12 113-140... 

Mayer, U., Gutmann, V. Phenomenological Approach to Cation-Solvent Interactions. Vol. 12, pp. 113-140. 

V. Gutmann and E. Wychera, Inorg. Nucl. Chem. Lett., 2 (1966) 257 V. Gutmann, Coordination Chemistry in Non-Aqueous Solutions, Springer, Vienna, 1968 V. Gutmann, The Donor-Acceptor Approach to Molecular Interactions, Plenum Press, London, 1978. 

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