Vibrational spectra of the charge transfer complexes between organic sulfides and iodine

Abstract

I.r. spectra of the charge transfer complexes between nine organic sulfides (as well as diethylselenide) with iodine were recorded between 1500 and 400 cm −1 in CS 2 and CCl 4 solutions and in the region 600-50 cm −1 in C 6H 12 and C 6H 6 solutions. Raman spectra of the complexes were recorded below 600 cm −1. For each system, i.r. and Raman bands in the 200-160 cm −1 were assigned to the II stretching mode of the complex. Additional i.r. bands below 160 cm −1, absent in Raman, were ascribed to intermolecular SI stretching vibrations. The integral intensities of these bands were determined and correlated with the thermodynamic functions. Some Raman active fundamentals of 1,4-dithiane became i.r. active in the iodine complex in accordance with a break down of the C 2 h symmetry. A force constant calculation was carried out for the dimethylsulfide-iodine complex and simplified calculations of the three point mass models were made for all the systems.