$^1H$ and $^{13}C$ NMR investigations of N,N'-bis(2- and 3-pyridinyl)-2,6-pyridine dicarboxamides

$^IH NMR$ spectra of N,N'-bis(2-pyridinyl)-2,6- pyridinedicarboxamides (1 to 3) and N,N'-bis(3-pyridinyl)-2,6-pyridinedicar- boxamide (4) have been analysed using the COSY spectra. Accurate IH chemical shifts and coupling constants have been obtained from the simulation of the resolution enhanced spectra. $^{13}C NMR$ spectra were analysed with the help of HETCORR and proton coupled $^{13}C$ spectra. The $^{13}C-^H$ coupling constants were obtained by the simulation of the proton coupled $^{13}C NMR$ spectra. From $^1H NMR$ spectra and NOE enhancements, it is inferred that the two 2-pyridyl rings of 1 to 3 are coplanar with the amide plane, while the 3-pyridyl ring of 4 is out of the amide plane