organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
through the S and hydrazinic N atoms, although there are
examples of them acting as monodentate ligands binding only
through sulfur (Valdes-Martines et al., 1996). The crystal
structure analysis described here is of the most simple parent
compound, (I), and will provide a reference for comparison
with more complex homologues.
ISSN 0108-2701
Acetone-4-methylthiosemicarbazone
at 220 K
Simon Parsons, Andrew G. Smith, Peter A. Tasker and
David J. White*
The asymmetric unit of (I) with the atomic numbering
scheme and intramolecular hydrogen bonding is shown in
Fig. 1. The molecule is almost planar with the maximum
Department of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh
EH9 3JJ, Scotland
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deviation of 0.012 A from the least-squares plane seen for S1.
Correspondence e-mail: d.j.white@ed.ac.uk
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The r.m.s. deviation from the least-squares plane is 0.006 A.
Received 23 August 1999
As with related molecules the CÐS bond length is indicative
of a double bond, con®rming that the molecule adopts the
thione tautomeric form in agreement with spectroscopic data
obtained for (I). Typically for this type of molecule the S and
hydrazinic N atoms are mutually trans which allows for a weak
intramolecular hydrogen bond between N4 and N2 [N4Á Á ÁN2
Accepted 9 November 1999
In the title compound, C5H11N3S, the trans conformation is
stabilized by a weak intramolecular NÐHÁ Á ÁN hydrogen
bond. Unusually, one NÐH bond is not involved in any
hydrogen-bond interactions and instead the molecules form a
one-dimensional polymer via NÐHÁ Á ÁS intermolecular
hydrogen bonds.
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2.629 (3), H4Á Á ÁN2 2.18 (3), N4ÐH4 0.85 (3) A, N4ÐH4Á Á ÁN2
113 (2)ꢀ]. Such contacts have been observed in other deriva-
tives (Park & Ahn, 1985). The availability of the lone pair on
N4 imparts some double-bond character to the N4ÐC1 bond
and it is shorter than that seen in 4-aryl derivatives (Palenik et
al., 1974) but comparable to other reported 4-alkyl derivatives
(Park & Ahn, 1985). In addition to the weak intramolecular
interaction, H4 is involved in a stronger intermolecular
contact to S1 in an adjacent molecule {N4Á Á ÁS1i 3.492 (3),
Comment
Thiosemicarbazides and thiosemicarbazones are known to
exhibit biological activity (Agrawal et al., 1972; Nandi et al.,
1986; Chattopadhyay et al., 1988) including antibacterial
(Nandi et al., 1984) and infertility (Nagarajan et al., 1984)
properties. These properties are thought to arise from the
metal chelating ability of these ligands, and this has led to
considerable interest in their coordination chemistry. In
almost all cases the ligands are bidentate and bind to the metal
i
i
ꢀ
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H4Á Á ÁS1 2.69 (2), N4ÐH4 0.85 (3) A, N4ÐH4Á Á ÁS1 157 (2)
1
2
1
[symmetry code: (i) x,
y,
+ z]}. This is shown in Fig. 1
2
and results in a planar one-dimensional hydrogen-bonded
polymer structure. In other systems, although hydrogen bonds
are prevalent, they lead to dimeric rather
than polymeric structures and involve the
strong hydrogen-bond donor unit N1ÐH1
(Chattopadhyay et al., 1988; Park & Ahn,
1985). Unusually, the hydrogen-bond
donor unit N1ÐH1 is not involved in any
intra- or intermolecular interactions in this
structure.
Experimental
N(4)-Methyl thiosemicarbazide and acetone
were purchased from the Aldrich Chemical Co.
and used as received. The compound was
synthesized by the method of Scovill (1991).
The ketone and carbazide were mixed in a 1:1
ratio in absolute ethanol with a catalytic
amount of concentrated sulfuric acid for 12 h.
Addition of aqueous sodium hydroxide to pH 8
precipitated the product which was collected by
®ltration. A suitable crystal was obtained by
Figure 1
A view of the molecule with atom-numbering scheme and showing intra- and intermolecular
slow cooling of a hot cyclohexane solution.
Because of physical constraints on the
hydrogen bonding. Displacement ellipsoids enclose 50% probability surfaces. [Symmetry code:
(i) x, 12 y,
1
2
+ z].
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Acta Cryst. (2000). C56, 237±238
Simon Parsons et al. C5H11N3S 237