FTIR study of H-bonds cooperativity in complexes of 1,2-dihydroxybenzene with proton acceptors in aprotic solvents: Influence of the intramolecular hydrogen bond

FTIR spectroscopic study of hydrogen bonding of 1,2-dihydroxybenzene (catechol) with proton acceptors has been carried out. The influence of intramolecular and intermolecular hydrogen bonds on the strengths of each other in complexes of 1,2-dihydroxybenzene with various proton acceptors has been analyzed. It was shown that intramolecular hydrogen bond is strengthened when 1,2-dihydroxybenzene interacts with bases (ethers, amines, nitriles, etc.) in inert solvents. The contribution of the cooperativity of intramolecular hydrogen bonds in the frequency of stretching vibrations of O–H groups linearly depends on the proton acceptor ability of the bases. The solvent effect on hydrogen bond cooperativity in 1,2-dihydroxybenzene–base complexes has been studied. The approach to determine the influence of cooperative effects on the formation of intermolecular complexes with 1,2-dihydroxybenzene is proposed. It was shown that the strength of intramolecular hydrogen bonds in the complexes of 1,2-dihydroxybenzene with bases due to cooperativity of interactions increases by 30–70%, and the strength of intermolecular hydrogen bond by 7–22%.