title: Crystal structures of four chiral imine-substituted thio-phene derivatives.
abstract: A series of thio-phenes substituted in positions 2 and 5 by imine groups have been synthesized using a solvent-free approach, and their crystal structures determined. The substituents are chiral groups, and the expected absolute configuration for each mol-ecule was confirmed by refinement of the Flack parameter. The compounds are 2,5-bis-[(S)-(+)-(1,2,3,4-tetra-hydro-naphthalen-1-yl)imino]-thio-phene, C26H26N2S, (I), 2,5-bis-{[(R)-(-)-1-(4-meth-oxy-phen-yl)eth-yl]imino-meth-yl}thio-phene, C24H26N2O2S, (II), 2,5-bis-{[(R)-(-)-1-(4-fluoro-phen-yl)eth-yl]imino-meth-yl}thio-phene, C22H20F2N2S, (III), and 2,5-bis-{[(S)-(+)-1-(4-chloro-phen-yl)eth-yl]imino-meth-yl}thio-phene, C22H20Cl2N2S, (IV). A common feature of all four mol-ecules is the presence of twofold symmetry. For (I), which crystallizes in the triclinic space group P1, this symmetry is non-crystallographic, but for (II) in C2 and the isomorphous structures (III) and (IV) that crystallize in P21212, the twofold symmetry is crystallographically imposed with one half of each mol-ecule in the asymmetric unit. The comparable mol-ecular symmetry in the four structures is also reflected in similar packing, with mol-ecules aggregated to form chains through weak C-H⋯S inter-actions.
authors.affiliation: Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Hernández-Téllez
authors.affiliation: Instituto de Física, Universidad Autónoma de Puebla, Av. San Claudio y 18 Sur, 72570 Puebla, Pue., Mexico.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Bernès
authors.affiliation: Centro de Química, Instituto de Ciencias, Universidad Autónoma de Puebla, 72570 Puebla, Pue., Mexico.
authors.forename: Angel
authors.initials: A
authors.lastname: Mendoza
authors.affiliation: Centro de Química, Instituto de Ciencias, Universidad Autónoma de Puebla, 72570 Puebla, Pue., Mexico.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Ríos-Merino
authors.affiliation: Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico.
authors.forename: Gloria E
authors.initials: GE
authors.lastname: Moreno
authors.affiliation: Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico.
authors.forename: Oscar
authors.initials: O
authors.lastname: Portillo
authors.affiliation: Laboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, A.P. 1067, 72001 Puebla, Pue., Mexico.
authors.forename: René
authors.initials: R
authors.lastname: Gutiérrez
keywords: Schiff base; bis-imine; crystal structure; thio­phene