Antimony pentachloride/adduct formation

Olofsson, G. and Olofsson, 1. (1973) Comparison between enthalpies of formation of antimony pentachloride adducts in carbon tetrachloride and in 1,2-dichloroethane solution. J. Am. Chem. 5cc., 95, 7231-7233. 

The donor number has been defined as the negative AH values for the formation of 1 1 adduct between solvents and antimony pentachloride, in 1,2-dichloroethane, at 25 °C8. In equilibrium 1, S is the solvent (with an unshared electron pair). 

The monoxide SgO forms the 0-bonded adduct SgO SbCl5 upon treatment with antimony pentachloride in CSy adduct formation results in pyramidal inversion at the three-coordinate sulfur atom. In contrast, the treatment of 850 with antimony pentachloride induces dimerisation to give the 2 1 adduct of SbCls with the cyclic dioxide SiyOy. The chair form of the two S O constituents of this dimerisation process are evident in the conformation of the 12-membered S12 ring in the adduct. 

An empirical semiquantitative measure of the nucleophilic properties of EPD solvents is provided by the so-called donor number DN (or donicity) of Gutmann [53, 67] [cf. also Section 7.2). This donor number has been defined as the negative A// values for 1 1 adduct formation between antimony pentachloride and electron-pair donor solvents (D) in dilute solution in the non-coordinating solvent 1,2-dichloroethane, according to Eq. (2-10) f... 

Due to its oxygen atoms, acetic anhydride is an electron pair donor in very much the same fashion as THF. The donor number DN (defined as the negative enthalpy of reaction for a 1 1 adduct formation between antimony pentachloride and the electron pair... 

The solvent donor number, first defined by Gutman [4] and abbreviated to DN, is a system specific, but quantitative measure of the ability of a substance to act as an electron pair donor. In its original form it is defined as the negative of the heat of reaction for the formation of the 1 1 adduct between the test substance and antimony pentachloride, measured in 1,2-dichloroethane as solvent (equation 12.2). 

Olofsson, G. (1964) Heats of formation of adducts between antimony pentachloride and some ketones and carboxylic esters. Acta Chem. Scand, 18, 11-17. 

The donor numbers (DN kcal mol" ) are a measure of the coordinating ability of a solvent. They have been defined as the negative AH values for l l-adduct formation between antimony pentachloride and an electron pair donor solvent (D) in dilute solution of a non-coordinating solvent (1,2-dichloroethane), according with Eq. 4.1. 

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