Nuclear quadrupole resonance of charge transfer complexes. Part 3.—A 14N and 35Cl n.q.r. study of the 1:1 complex of 3,5-dichloropyridine with iodine monochloride

Abstract

The infrared, Raman and n.q.r. (¹⁴N and ³⁵Cl) spectra of the 1:1 molecular complex of 3,5-dichloropyridine with iodine monochloride are reported. All three ¹⁴N transition frequencies were obtained at 77 K using a double resonance technique. The resulting ¹⁴N coupling constant and asymmetry parameter are 2.257 MHz and 0.208 respectively. The vibrational and ³⁵Cl n.q.r. spectra indicate that the degree of charge transfer in this compound is almost the same as in the corresponding pyridine and 4-methylpyridine complexes. The ¹⁴N results are interpreted in terms of a model in which charge is transferred from the nitrogen lone pair orbital to the halogen molecule. The degree of charge transfer indicated by the ¹⁴N and halogen n.q.r. results are in good agreement.