Conformation of cationic N,N-dimethylglycine in dimethylglycinium trifluoroacetate.
In the title compound, C(4)H(10)NO(2)(+).C(2)F(3)O(2)(-), the main N-C-COOH skeleton of the protonated amino acid is nearly planar. The C=O/C-N and C=O/O-H bonds are syn and the two methyl groups are gauche to the methylene H atoms. The conformation of the cation in the crystal is compared to that given by ab initio calculations (Hartree-Fock, self-consistent field molecular-orbital theory). The trifluoroacetate anion has the typical staggered conformation with usual bond distances and angles. The cation and anion form dimers through a strong O-H.O hydrogen bond which are further interconnected in infinite zigzag chains running parallel to the a axis by N-H.O bonds. Weaker C-H.O interactions involving the methyl groups and the carboxy O atoms of the cation occur between the chains.
Rodrigues
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VH
CEMDRX, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, P-3004-516 Coimbra, Portugal.
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D018360:Crystallography, X-Ray; D019587:Dietary Supplements; D008968:Molecular Conformation; D012492:Salts; D012521:Sarcosine / Q000031:analogs & derivatives / Q000737:chemistry*; D014269:Trifluoroacetic Acid / Q000737:chemistry*
D012492:Salts; C025138:dimethylglycine; D014269:Trifluoroacetic Acid; D012521:Sarcosine