engleski

Molecular Structure and Acid/Base Properties of 1, 2-dihydro-1, 3, 5-triazine Derivatives

It is shown that guanidine and its N, N-dimethyl- derivative react with substituted carbodiimides, affording hithertho unknown 1, 2-dihydro-1, 2, 3-triazine derivatives. The structures of three novel compounds of this type and their perchlorate salts were proved by spectroscopic (IR, 1H and 13C NMR and 15N solid-state NMR) and X-ray diffraction methods. The acid/base properties were also determined experimentally and by using DFT calculations with the B3LYP functional. The most basic compound was found to be dihydrotriazine 3, the basicity of which with the pKa value of 23.3 is of the same order of magnitude as that of tetramethylguanidine. Acidity measurements revealed that all the compounds studied are very weak acids with pKa values in the range of 25.8 - 30.8 pKa units in acetonitrile.

triazines; basicity; DFT calculations

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