A COMPUTATIONAL STUDY ON THE HYDROGEN-BONDED COMPLEXES FORMED BY THE ANTHYRIDONE AND DIALDEHYDE DERIVATIVES

Abstract

A theoretical study on hydrogen-bonded complex 1 formed by anthyridone (monomer A) and 2,6-diaminopyridine-3,5-dialdehyde (monomer B) was performed using the AM1 method to obtain its binding energy. A series of complexes 2 to 9 were designed by changing the R-groups on monomer A in complex 1 into C₆H₅, p-toluene, p-phenol, OH, OCH₃, and turning the X-groups on monomer B into F, Cl, I, respectively. Based on the optimized geometries, the electronic spectra for the complexes were calculated with the INDO/CIS method and the IR spectra were computed utilizing the AM1 method. It was indicated that the dimer could be formed by the two monomers via triple hydrogen bonds because of its negative binding energy. The binding energies of the complexes were changed with the change of the electronic properties and steric effects of the substituents on the monomers. The first absorptions in the electronic spectra of the complexes were red-shifted compared with those of the monomers. The stretching vibrations of the N-H bonds on the monomers were weakened and their frequencies were reduced with the formation of the hydrogen bonds.

KEY WORDS: Anthyridone, 2,6-Diaminopyridine-3,5-dialdehyde, Hydrogen bonding, IR spectra, AM1


Bull. Chem. Soc. Ethiop. 2007, 21(2), 263-270.