Different packing motifs of isomeric (E)- N'-(halo-phenyl-methyl-idene)- N-methyl-2-(thio-phen-2-yl)acetohydrazides controlled by C-H⋯O inter-actions

Laura N F Cardoso; Thais C M Noguiera; James L Wardell; Marcus V N de Souza; William T A Harrison

doi:10.1107/S2056989018001251

Different packing motifs of isomeric (E)- N'-(halo-phenyl-methyl-idene)- N-methyl-2-(thio-phen-2-yl)acetohydrazides controlled by C-H⋯O inter-actions

Acta Crystallogr E Crystallogr Commun. 2018 Feb 7;74(Pt 3):313-318. doi: 10.1107/S2056989018001251. eCollection 2018 Mar 1.

Authors

Laura N F Cardoso^{1

2}, Thais C M Noguiera¹, James L Wardell^{1

3}, Marcus V N de Souza¹, William T A Harrison³

Affiliations

¹ Fundação Oswaldo Cruz, Instituto de Tecnologia em Fármacos-FarManguinhos, Rua Sizenando Nabuco, 100, Manguinhos, 21041-250 Rio de Janeiro, Brazil.
² Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil.
³ Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland.

Abstract

The crystal structures of three isomeric (E)-N'-(chloro-phenyl-methyl-idene)-N-methyl-2-(thio-phen-2-yl)acetohydrazides (C₁₄H₁₃ClN₂OS) are described, with the Cl atom in ortho (I), meta (III) and para (IV) positions in the benzene ring. The ortho-bromo derivative (II) (C₁₄H₁₃BrN₂OS), which is isostructural with its chloro congener (I), is also reported. Mol-ecules (I)-(III) have similar conformations, which approximate to l-shapes, as indicated by their N-C-C-C_t (t = thio-phene) torsion angles of -90.1 (3), -91.44 (18) and -90.7 (9)°, respectively. The conformation of (IV) is different, with an equivalent torsion angle of -170.75 (11)° corresponding to a more extended shape for the mol-ecule. The thio-phene ring in each structure features 'flip' rotational disorder. The packing for (I) and (II) features inversion dimers, linked by pairs of C-H⋯O inter-actions, which generate R₂²(14) loops. In the crystal of (III), [010] C(8) chains arise, with adjacent mol-ecules linked by pairs of C-H⋯O hydrogen bonds. The packing for (IV) features unusually short C-H⋯O inter-actions arising from an H atom attached to the benzene ring (H⋯O = 2.18 Å), which lead to C(9) [301] chains. Hirshfeld fingerprint percentage contact contributions are similar for the four title compounds.

Keywords: carbohydrazide; crystal structure; methylation; weak hydrogen bonds.