Enthalpy diiodine complexes

Many correlations between the complexation enthalpy and the Gibbs energy of complexation have been proposed, for example the SbCls complexes [78], the diiodine complexes [4] or the hydrogen-bonded complexes [84]. They have been explained either by a quasi-isoentropic behaviour of the complexation reaction or by an enthalpy-entropy compensation effect (Equation 1.90) ... 

There have been many determinations of the enthalpy of complexation of diiodine with Lewis bases. The data measured in alkanes and/or CCU are collected in Table 5.25. It is difficult, however, to assemble a reliable diiodine affinity scale from these values. The reasons are that many results appear inaccurate and determinations have been made in... 

The charge-transfer complex of 1,4,7-trithiacyclononane 10 and I2 has been prepared by slow evaporation of solutions containing I2 and thioether macrocycle in CH2CI2. The structure of the complex showed two independent macrocycles in the asymmetric unit which are linked by a diiodine bridge. Asymmetric units are linked by iodine-iodine and sulfur-iodine interactions to form an extended array of linked macrocycles. The formation enthalpy ( AH = 35.0 kj mob1) and formation constant (K= 169 dm3 mol-1) of 1 1 adduct have been determined by electronic spectroscopy and compared to other polythia macrocycles of different sizes <1997JCD1337>. 

Figure 1,2 Enthalpy-entropy plot for the complexation of diiodine with NHj, MeNH2, EtNH2, BuNH2, Me2NH, Et2NH and piperidine in heptane.

Determination of the Complexation Enthalpy and Entropy of Diiodine with Dimethyl Sulfoxide by Visible Spectrometry... 

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