The structure investigations of dehydroacetic acid and 1,8-diaminonaphthalene condensation product by NMR, MS, and X-ray measurements

• The unusual ionic product (dhaDAN) was synthesized.
• The discussion about structure of possible reaction products was done.
• NMR in DMSO and solid state, and MS studies of dhaDAN were carried out.
• The crystal structure of dhaDAN has been solved by X-ray crystal analysis.
• dhaDAN exists as ionic species connected by two different hydrogen bonds.

A new unexpected product of condensation reaction of 1,8-diaminonaphthalene (DAN) and carbonyl compound (here: dehydroacetic acid (dha)) was synthesized. Discussion about the molecular structure of possible products of this reaction was done on the base of NMR studies. The structure of the titled product in both DMSO solution and in the solid state was resolved by analysis of its spectral data (X-ray structure analysis, multinuclear NMR in solution and solid state spectra) and MS measurements. The presented studies provided clear evidence that the titled product exists in diluted DMSO solution as the mixture of two kinetic free ionic species whereas in concentrated DMSO solution as well as in the solid state this system forms associated ionic pairs bonded together by hydrogen bonds.

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