Theoretical and experimental comparative study of a derivative from 2-pyridinecarboxaldehyde which exhibits configurational dynamics

• It is presented a crystallographic structure that reveals the syn and anti conformers coexistence in solid state.
• By DFT methods molecular structure, vibrational properties, 13C and 1H NMR were calculated.
• The E/Z photoisomerization of the (E)-4-nitro-N′-(pyridine-2-ylmethylene)benzohydrazide was studied by 1H NMR.

The (E)-4-nitro-N′-(pyridine-2-ylmethylene)benzohydrazide, a derivative from 2-pyridinecarboxaldehyde, displays E/Z isomerization induced by ultraviolet radiation in which the process of photoisomerization was evidenced and followed by 1D 1H NMR. The structure of the compound was determined by FT-IR and NMR techniques and confirmed by single-crystal X-ray diffraction. The results in terms of bond angle and length, chemical shift (13C and 1H) and vibrational frequencies obtained experimentally were compared to computed values at two levels of theory (Restricted Hartree–Fock and Density Functional Theory) using different basis set. The understanding of spectroscopy and dynamic properties of these type of compounds is of importance in view of their potential use in molecular machines and electronic devices.

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