title: Synthesis, structural determination and dynamic behavior of 2-chloro-4,6-bis(pyrazolylamino)-1,3,5-triazines.
abstract: A series of 2-chloro-4,6-bis(pyrazolylamino)-1,3,5-triazines with applications in crystal engineering have been prepared. At low temperature, the presence of two or three isomers has been detected and these assigned to 4,6-diamino-1,3,5-triazine structures on the basis of comparison with model compounds. 2D-Exchange spectroscopy studies in various solvents and at different temperatures have been used to determine the equilibrium constants and the activation free energies of the restricted rotation about the amino-triazine bond. A plot of the activation free energy versus temperature showed a good linear correlation and confirmed that the same process is present in all of the compounds under investigation. Comparison with model compounds also confirmed both the occurrence of the restricted rotation and the 4,6-diamino-1,3,5-triazine tautomerism for triazines 1-4 in solution. The structure of compound 1 has been determined in the solid state by X-ray crystallography and consists ofa 4,6-diamino- 1,3,5-triazine structure stabilized by intra and intermolecular hydrogen bonds.
authors.affiliation: Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Ciencias Químicas, Universidad de Castilla-La Mancha, Ciudad Real, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Díaz-Ortiz
authors.forename: José
authors.initials: J
authors.lastname: Elguero
authors.forename: Concepción
authors.initials: C
authors.lastname: Foces-Foces
authors.forename: Antonio
authors.initials: A
authors.lastname: de la Hoz
authors.forename: Andrés
authors.initials: A
authors.lastname: Moreno
authors.forename: Sergio
authors.initials: S
authors.lastname: Moreno
authors.forename: Ana
authors.initials: A
authors.lastname: Sánchez-Migallón
authors.forename: Gema
authors.initials: G
authors.lastname: Valiente
mesh_terms: D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013237:Stereoisomerism; D013696:Temperature; D013816:Thermodynamics; D014227:Triazines / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D014227:Triazines