Hydrogen-bonded complexes of 2-aminopyrimidine-parabenzoquinone in an argon matrix

The H-bonded complexes of 2-aminopyrimidine (NH2 Py) with parabenzoquinone (Qu) in a low-temperature argon matrix are investigated by the method of IR spectroscopy. The IR absorption spectra in the spectral range 400-3600 cm-1 are obtained for different concentration ratios of these compounds at a temperature of 11 K. The molar integrated absorption coefficients in the bands of the stretching modes of the free and H-bonded NH2 group are determined. Quantum-mechanical calculations of the IR spectra of the NH2 Py and Qu molecules and their dimers are carried out. A comparison of the experimental and calculated results permits the conclusion that NH2 Py-Qu dimers in an argon matrix have a planar structure with two weak hydrogen bonds, NH⋯O and CH⋯N.