Structural and theoretical studies of 4-chloro-2-methyl-6-oxo-3,6-dideuteropyrimidin-1-ium chloride (d 6).
Acta Crystallogr E Crystallogr Commun
; 77(Pt 4): 390-395, 2021 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-33936763
ABSTRACT
The title compound, C5D6ClN2O+·Cl-, crystallizes in the ortho-rhom-bic space group, Pbcm, and consists of a 4-chloro-2-methyl-6-oxo-3,6-di-hydro-pyrimidin-1-ium cation and a chloride anion where both moieties lie on a crystallographic mirror. The cation is disordered and was refined as two equivalent forms with occupancies of 0.750â
(4)/0.250â
(4), while the chloride anion is triply disordered with occupancies of 0.774â
(12), 0.12â
(2), and 0.11â
(2). Unusually, the bond angles around the C=O unit range from 127.2â
(6) to 115.2â
(3)° and similar angles have been found in other structures containing a 6-oxo-3,6-di-hydro-pyrimidin-1-ium cation, including the monclinic polymorph of the title compound, which crystallizes in the monoclinic space group P21/c [Kawai et al. (1973 â¸). Cryst. Struct. Comm. 2, 663-666]. The cations and anions pack into sheets in the ab plane linked by N-Hâ¯Cl hydrogen bonds as well as C-Hâ¯O and Clâ¯O inter-actions. In graph-set notation, these form R 3 3(11) and R 3 2(9) rings. Theoretical calculations seem to indicate that the reason for the unusual angles at the sp 2 C is the electrostatic inter-action between the oxygen atom and the adjacent N-H hydrogen.
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Revista:
Acta Crystallogr E Crystallogr Commun
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Estados Unidos