Crystal structures of crotonaldehyde semicarbazone and crotonaldehyde thiosemicarbazone from X-ray powder diffraction data

Abstract

Crotonaldehyde semicarbazone {systematic name: (E)-2-[(E)-but-2-en-1-ylidene]hydrazinecarboxamide}, C5H9N3O, (I), and crotonaldehyde thiosemicarbazone {systematic name: (E)-2-[(E)-but-2-en-1-yldene]hydrazinecarbothioamide}, C5H9N3S, (II), show the same E conformation around the imine C=N bond. Compounds (I) and (II) were obtained by the condensation of crotonaldehyde with semicarbazide hydrochloride and thiosemicarbazide, respectively. Each molecule has an intramolecular N—H...N hydrogen bond, which generates an S(5) ring. In (I), the crotonaldehyde fragment is twisted by 2.59 (5)° from the semicarbazide mean plane, while in (II) the corresponding angle (with the thiosemicarbazide mean plane) is 9.12 (5)°. The crystal packing is different in the two compounds: in (I) intermolecular N—H...O hydrogen bonds link the molecules into layers parallel to the bc plane, while weak intermolecular N—H...S hydrogen bonds in (II) link the molecules into chains propagating in [110].

Keywords

• crystal structure
• crotonaldehyde
• semicarbazone
• thiosemicarbazone
• powder X-ray diffraction
• supramolecular structure
• hydrogen bond
• one-dimensional chain
• two-dimensional networks