1H NMR spectra of E and Z pyridine-2-carbaldehyde 2′-pyridylhydrazone and related compounds

Proton magnetic resonance spectra at 100 MHz are reported for the E- and Z-isomers of pyridine-2-carbaldehyd 2′- pyridylhydrazone in carbon tetrachloride, d₆-dimethylsulphoxide and d₆-benzene solutions, and for various monomethylated derivatives in d₆-dimethylsulphoxide. The spectral parameters obtained by analysis with the help of LAOCOON 3 are discussed in terms of solvent effects and the chemical shift changes consequent upon isomerisation are evaluated. Some conclusions are reached concerning the preferred conformations of the E- and Z-isomers of pyridine-2-carbaldehyde 2′-pyridylhydrazone.