Theoretical study of intramolecular hydrogen bond on 2-(2-Hydroxy phenyl)-5(4H)-Oxazolone halogenated derivatives in ground state

Abstract Intramolecular hydrogen bond (IHB) of 2-(2-Hydroxy phenyl)-5(4H)-Oxazolone(HPO) halogenated derivatives in the ground have been investigated by DFT method with the standard basis set 6-311 + +G (d,p). In this work, we evaluated and compared the substitution effects on the IHB strength by some of the IHB descriptors such as geometrical, topological and orbital charge transfer parameters. As with replacing of the halogen atoms at R1 position the IHB energies increased while for the R2, R3 and R4 decreased. Finally, the linear equations of the IHB energies versus the IHB descriptors parameters show that the open-close method (OPM) is inappropriate for calculation of the IHB energies in the HPO