Structural studies of PCU-hydrazones: NMR spectroscopy, X-ray diffractions, and DFT calculations

► The structures of PCU-hydrazones were investigated by NMR, X-ray and DFT calculations. ► Calculated isomer values were correlated with the experimental chemical shifts. ► The NMR signal assignments for the PCU-hydrazones were confirmed by 1D and 2D NMR.