STRUCTURE AND SPECTROSCOPIC BEHAVIOR OF THE SOLID ADDUCT OF 3-METHYLPYRIDINE WITH 2,6-DICHLORO-4-NITROPHENOL

The structure of the adduct of 3-methylpyridine with 2,6-dichloro-4-nitrophenol has been determined by X-ray diffraction. The crystals are monoclinic, space group P2(1)/c with a = 7.935(2), b = 23.789(7), c = 7.521(2)angstrom, beta = 112.44(2)degrees and Z = 4. The structure solved by direct methods was refined to R = 0.040 for 1564 non-zero independent reflections. The complex is characterized by one of the shortest N-H...O hydrogen bridges with the N...O distance equal to 2.544(4)angstrom. Both the estimated localization of the proton and the C-O bond length (1.285(4)angstrom) indicate that the proton is transferred from oxygen to nitrogen. In contrast, the UV and IR spectra imply a double minimum potential for the proton motion.