C-13 AND N-15 SOLID-STATE NMR OF PARTIALLY METHYL-SUBSTITUTED POLYAZINES

The partially methylated polyazine series, which varies the number of methyl groups along the polyazine backbone, has been prepared. The number and substitution pattern of methyl groups were altered via a condensation reaction between an alpha,beta-dicarbonyl and an alpha,beta-dihydrazone using glyoxal, pyruvic aldehyde, 2,3-butanedione, glyoxal dihydrazone, pyruvic aldehyde dihydrazone, and 2,3-butanedione dihydrazone. All combinations of the above reagents were used, leading to nine different polymers. The polymers prepared with glyoxal dihydrazone exhibit hydroxy-bearing defects like those in the unsubstituted polyazine. In contrast, the polymers prepared with 2,3-butanedione dihydrazone were essentially defect-free, like the permethyl and higher alkyl polyazines. However, the polymers prepared with pyruvic aldehyde dihydrazone failed to follow a simple trend.