SPECTRAL MANIFESTATIONS OF NONADDITIVITY OF HYDROGEN-BONDS IN COMPLEXES OF SUBSTITUTED ANTHRANILIC ACIDS

In IR spectra of complexes of N-methyl- and N-phenylanthranilic acids with acceptors of the RCOOH...B type, the nuNH band of the group takin g part in the intramolecular hydrogen bond NH...O=C shifts to lower fr equencies with an increase of the proton accepting ability of B. The i ntermolecular hydrogen bond of the C=O...HX type of methyl esters of t hese acids with proton donors results in a decrease of the nuNH freque ncy. The strengthening (weakening) of the intramolecular bond is cause d by a shift of electron density towards (from) the proton accepting s ite under the influence of the external proton acceptor (donor). The w hole effect of the cooperative and anticooperative influence of the in termolecular hydrogen bond on the intramolecular hydrogen bond reaches 100-130 cm-1.