6533b861fe1ef96bd12c4f8c
RESEARCH PRODUCT
6-Methyluracil: a redetermination of polymorph (II)
Gustavo Portalonesubject
supramolecular chemistry; crystal engineering; nucleobasecrystal structure010405 organic chemistryChemistryHydrogen bondUracilCrystal structurenucleobases010402 general chemistry01 natural sciencessupramolecular chemistry0104 chemical sciencesNucleobaseCrystalchemistry.chemical_compoundCrystallographycrystal engineeringGroup (periodic table)lcsh:QD901-999Canonical formlcsh:CrystallographynucleobaseMonoclinic crystal systemdescription
6-Methyluracil, C5H6N2O2, exists in two crystalline phases: form (I), monoclinic, space group P21/c [Reck et al. (1988). Acta Cryst. A44, 417–421] and form (II), monoclinic, space group C2/c [Leonidov et al. (1993). Russ. J. Phys. Chem. 67, 2220–2223]. The structure of polymorph (II) has been redetermined providing a significant increase in the precision of the derived geometric parameters. In the crystal, molecules form ribbons approximately running parallel to the c-axis direction through N—H...O hydrogen bonds. The radical differences observed between the crystal packing of the two polymorphs may be responsible in form (II) for an increase in the contribution of the polar canonical forms C—(O−)=N—H+ relative to the neutral canonical form C(=O)—N—H induced by hydrogen-bonding interactions.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2019-06-01 | IUCrData |