Two- and Three-Centered Hydrogen Bonds Involving Organic Fluorine Stabilize Conformations of Hydrazide Halo Derivatives: NMR, IR, QTAIM, NCI, and Theoretical Evidence.

The presence of two- and three-centered hydrogen bonds (HB) of the type H(N)···X-C and C═O···H(N)···X-C, respectively, involving organic fluorine in the synthesized hydrazide halo derivatives have been convincingly established by extensive multidimensional NMR studies. The stabilized conformation of the molecules involving two- and three-centered HBs derived by NMR studies have been further confirmed by density functional theory (DFT)-based calculations, such as quantum theory of atoms in molecules (QTAIM), noncovalent interaction (NCI), and relaxed potential energy scan.