E. Bednarek, B. Modzelewska-Banachiewicz, M. Cyrański
May 2, 2001
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Influential Citations
12
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Journal
Journal of Molecular Structure
Abstract
Abstract The 5-carboxymethyl-1,2,4-triazole ( 1 , 2 , 3 ) and 5-oxo-1,2,4-triazine ( 4 , 5 , 6 ) derivatives were examined in solution by the 1 H, 13 C and 15 N NMR including g -HSQC, g -HMBC 2D techniques and in the solid phase by 13 C CPMAS NMR. Molecular modelling shows that there is not enough space for free rotation of neighbouring substituents at C 3 and N 4 and the two rings, especially in 4 – 6 , should be twisted with respect to the central heterocyclic system. The X-ray diffraction analysis of 2 and 5 evidenced that in the crystal of 2 the twist angles of 2-pyridyl and phenyl rings are 20.4 and 74.0° whereas in 5 they are 51.6 and 80.5°, respectively. Intramolecular hydrogen bonds N 1 H⋯OC are formed in triazines 4 – 6 in solution and in the solid state; the H⋯O distance in 5 is 2.079 A.