untersuchung der Molekularassoziation des (p-Chlorbenzolsulfonamido)benzolthiophosphonsäure-O-äthylesters mit Hilfe der IR-Spektroskopie

O-Ethyl (p-chlorobenzenesulfonamido)benzenethiophosphonate (1) is shown to be associated by hydrogen-bonding by means of its i.r. spectrum in CCl₄ solution. Quantitative examination allows to determine the dissociation konstantK, the temperature dependence of which leads to a H-value of 8.3 kcal/mole. From this value it is concluded that the associated molecules are cyclic dimers2. The comparison of the H- and pK-values with the corresponding data of other compounds which form cyclic dimers, shows that the strength of the hydrogen bonding is greater in those compounds which possess smaller pK-values.

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XLIV. Mitt.:L. Almasi, N. Popovici undJ. Zsakó, Chem. Ber.106, 1384 (1973).