title: On substituted pyrazole derivatives. II. (E)-1-(4-{[1-(4-Fluorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl]diazenyl}phenyl)ethanone and (E)-1-(4-chlorophenyl)-3,5-dimethyl-4-[2-(2-nitrophenyl)diazenyl]-1H-pyrazole.
abstract: The molecular structures of (E)-1-(4-{[1-(4-fluorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl]diazenyl}phenyl)ethanone, C19H17FN4O, (III), and (E)-1-(4-chlorophenyl)-3,5-dimethyl-4-[2-(2-nitrophenyl)diazenyl]-1H-pyrazole, C17H14ClN5O2, (IV), prepared by reaction of the corresponding β-diketohydrazones with substituted arylhydrazines in acid media, are nonplanar, with the planes of the lateral phenyl rings forming dihedral angles with that of the central pyrazole ring varying from 2.71 (7) to 45.22 (7)°. The crystal structures are supported by C-H...O, C-H...π and π-π weak intermolecular interactions together with some unusual trifurcated C-Cl...Cl-C contacts, which are discussed in detail.
authors.affiliation: Instituto de Ciencias Químicas, Universidad Austral de Chile, Avenida Los Robles s/n, Campus Isla Teja, Casilla 567, Valdivia, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Bustos
authors.affiliation: Departamento de Ciencias Físicas, Universidad Andrés Bello, República 220, Santiago de Chile, Chile.
authors.forename: Luis
authors.initials: L
authors.lastname: Alvarez-Thon
authors.affiliation: Departamento de Ciencias Físicas, Universidad Andrés Bello, República 220, Santiago de Chile, Chile.
authors.forename: Tania
authors.initials: T
authors.lastname: Oportus
authors.affiliation: Instituto de Ciencias Químicas, Universidad Austral de Chile, Avenida Los Robles s/n, Campus Isla Teja, Casilla 567, Valdivia, Chile.
authors.forename: Angela
authors.initials: A
authors.lastname: Mesías-Salazar
authors.affiliation: Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Baggio
keywords: crystal structure; pharmaceutical compounds; substituted pyrazoles; trifurcated C—Cl...Cl—C interactions; weakly bound supramolecular structures