Synthesis and characterization of polymers containing naphthyl-2H-benzotriazoles, 3. Hydrogen bonding in monomers and polymers containing naphthyl-2H-benzotriazole

The UV absorption characteristics of a number of dihydroxynaphthyl-2H-benzotriazoles, their (meth)acryloyloxy derivatives and the corresponding polymers have been studied in a range of solvents of different polarity. It was shown that the formation of hydrogen bonds in these compounds strongly depends on the polarity of the solvent and an equilibrium exists between intramolecular and intermolecular hydrogenbonded states. The stability of the intramolecular hydrogen bond was determined quantitatively. The equilibrium between the intramolecular and the intermolecular hydrogen-bonded state of the molecule was strongly affected by the chemical structure of the naphthyl-2H-benzotriazole. The stability of the intramolecular hydrogen bond increased when electron-donating substituents were introduced into the benzotriazole or when the naphthyl-2-benzotriazole was fixed to a polymer backbone.