Magnetic circular dichroism spectra of iodide ion in solvents of low polarity

Abstract

The magnetic circular dichroism spectra of some alkylammonium iodides in solvents of low polarity have been measured and the results are discussed in terms of the current theories of the nature of the ion-pairs involved.

The spectra in dichloromethane and in tetrahydrofuran support the suggestion that in these solvents the solutes exist as solvent-shared ion-pairs, and that the excited state involved in capable of a gradual modification from that of the ion-pair to that of the free ion. The spectra in chloroform and carbon tetrachloride are quite different from those in the other solvents used and it is suggested that these spectra can be explained in terms of a lifting of the degeneracy of the valence p orbitals of the iodide ion due to the proximity of the cation in the contact ion-pair.