Theoretical and experimental NMR data of 3,5-dinitro-2-(2-phenylhydrazinyl)pyridine and of its 4- and 6-methyl derivatives

3,5-Dinitro-2-(2-phenylhydrazinyl)pyridine and its methyl derivatives: 4-methyl-3,5-dinitro-2-(2-phenylhydrazinyl)pyridine and 6-methyl-3,5-dinitro-2-(2-phenylhydrazinyl)pyridine were synthesized and characterized by 1H NMR and 13C NMR. Calculations were also performed where the above molecules were optimized using the methods of density functional theory (DFT) with 6-31G(d,p) and 6-311G(d,p) basis sets. For all molecules studied, the lowest energy was obtained using the 6-311G(d,p) basis set. The GIAO/DFT (Gauge Invariant Atomic Orbitals/Density Functional Theory) calculations on the 6-311G and 6-311++G and 6-311G** basis sets were carried out to determine proton and carbon chemical shifts and to find they were close to the experimental values. been also found that intramolecular hydrogen bonding exists between hydrogen atom (in 2-NH group) and oxygen atom (pyridine-3-NO2). Moreover, resonances between pyridine ring and electron withdrawing 3-nitro group as well between that ring and the lone electron pair of NH group favor a co-planarity of the structure; this means a chelate ring created by above-mentioned intramolecular hydrogen bond is almost co-planar with pyridine ring.