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X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects
Published on: June 8, 2016
Crystal structures of crotonaldehyde semicarbazone and crotonaldehyde thiosemicarbazone from X-ray powder diffraction
1Department of Chemistry, Atomic Energy Commission of Syria (AECS), PO Box 6091, Damascus, Syrian Arab Republic.
Abstract:
Crotonaldehyde semicarbazone {systematic name: (E)-2-[(E)-but-2-en-1-yl-idene]hydrazinecarboxamide}, C5H9N3O, (I), and crotonaldehyde thio-semi-carba-zone {systematic name: (E)-2-[(E)-but-2-en-1-yldene]hydra-zinecarbo--thio-amide}, 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 hydro-chloride and thio-semicarbazide, respectively. Each mol-ecule has an intra-molecular 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 thio-semicarbazide mean plane) is 9.12 (5)°. The crystal packing is different in the two compounds: in (I) inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into layers parallel to the bc plane, while weak inter-molecular N-H⋯S hydrogen bonds in (II) link the mol-ecules into chains propagating in [110].
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