A Scatchard-type equation has been derived that allows the determination of complex formation constants by nmr spectroscopy. The primary advantage of this equation is that K is determined directly from the slope of an experimental plot rather than from the intercept. In addition, it is possible to use the molar and molal versions of the same equation and to determine the molar volume of the pure donor component of the complex.A series of trinitrobenzene (TNB) complexes with sulfoxides, sulfides, and a disulfide have been analyzed by this technique. The complexes were studied in carbon tetrachloride, carbon disulfide, and 1,2-dichloroethane at 10, 20, and 30°. Complex formation constants and thermodynamic properties were determined. * To whom correspondence should be addressed.is red-shifted (ca. 30 nm) and becomes significantly more intense at the expense of the phosphorescence intensity. The polarization values remain significantly positive, indicating that the fluorescent state is of ( , *) character. Theoretical transition energies and direction of polarizations calculated by the P-P-P SCF MO Cl method have been used for the interpretation of the observed results. In addition, the electronic structures of the singlet and triplet excited states of coumarin have been obtained theoretically in an attempt to correlate them with the photochemical reactivity of coumarin.
The characterization of olefins with 2,4-dinitrobenzenesulfenyl chloride is described in a recent paper by N. Kharasch and C. M. Bueos, THIS JOURNAL, 71, 2724 (1949).(5) Compare also references 4 and 5 , and forthcoming papers of this series, for other uses of the reagent.(6) This reagent is now available from the Hexagon Laboratories,
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