IR spectra and crystal structure of hydrochlorides and complex salts of 2,3-polymethylene-3,4-dihydroquinazolines and-4-quinazolones

IR spectra are reconsidered on the basis of the results of x-ray structural analysis of the crystal structures of hydrochlorides and complex salts of 2,3-polymethylene-3,4-dihydroquinazolines and -4-quinazolones. It has been established that two absorption bands (NI+--H) in the complex salts charact erize different energies of formation of an H-bond which is weaker than in the corresponding hydrochlorides. The nature of an absorption band in the 3 400--3500 cm(-1) region has been established from the XSA results.