organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
6-ethoxycarbonyl-3,3,10,10-tetramethyl-1,2-dithia-5,8-diaza-
Ê
deca-4,8-diene [2.025 (1) A; Wrench et al., 1993]. This shorter
length may be mainly due to the intermolecular interaction of
the outward-branched 6-ethoxycarbonyl group from the ring
in the latter compound. The molecule contains two double
bonds (C4 N5 and C9 N8), with essentially planar atomic
ISSN 0108-2701
3,3,10,10-Tetramethyl-1,2-dithia-
5,8-diazacyclodeca-4,8-diene
Jem-Mau Lo,a Golam Mostafa,b Ling-Yin Chang,a Fen-Ling
Liaoc and Tian-Huey Lub*
aDepartment of Nuclear Science, National Tsing Hua University, Hsinchu, Taiwan,
bDepartment of Physics, National Tsing Hua University, Hsinchu, Taiwan, and
cDepartment of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
Correspondence e-mail: thlu@phys.nthu.edu.tw
Received 28 January 2004
Accepted 1 March 2004
Online 31 March 2004
Figure 1
The molecular structure of (I), showing 30% probability displacement
ellipsoids.
The title compound, C10H18N2S2, acts as an important
precursor for the synthesis of the pharmaceutically important
diaminedithiol ligand system. The molecule has a local twofold
axis and the arrangement of the S2N2 donor atoms in the
macrocycle is anticlinal.
arrangements [C3ÐC4 N5ÐC6 = 171.6 (2)ꢀ and C7Ð
N8 C9ÐC10 = 173.3 (2)ꢀ]. The torsion angles associated
with the donor atoms [N5 C4ÐC3ÐS2 = 123.8 (2)ꢀ and
N8 C9ÐC10ÐS1 = 123.4 (2)ꢀ] show that the donor-atom
arrangement is anticlinal. The bond distances (Table 1) are in
good agreement with standard values. The crystal structure is
mainly stabilized by van der Waals forces, and no hydrogen
bonds or ꢀ±ꢀ interactions are observed.
Comment
The diaminedithiol ligand system had been employed for
complexation with 99mTc to produce signi®cant radio-
pharmaceuticals (Lever et al., 1985; Cheesman et al., 1988;
Kung et al., 1989; Scheffel et al., 1998). Diaminedithiol ligands
have also been synthetically modi®ed into bifunctional
chelating agents for carrying 99mTc, as well as for coupling to
bioactive molecules, such as proteins, antibodies and peptides
(Baidoo & Lever, 1990; Baidoo et al., 1998). 99mTc-labelled
biomolecules exhibit the potential for use in non-invasive in
vivo imaging of cancers (Baidoo et al., 1998). In the synthesis
of diaminedithiol ligands, or of derivatives that are bifunc-
tional chelating agents, the title compound, (I), is an important
precursor. We describe here the preparation of (I) and its
X-ray crystal structure, which may further support its identi-
®cation by NMR and elemental analysis. The cyclic structure
of (I) is in contrast with the linear structure of the diamine-
dithiol compound obtained from a reduction reaction of (I)
(Baidoo & Lever, 1990; Baidoo et al., 1998).
Experimental
The title compound was synthesized following a procedure similar to
that reported by Merz & Specker (1963), by condensation of 2,2-
dithiobis(2-methylpropanal) with ethylenediamine in a 1:5 molar
ratio. The former compound was synthesized from the reaction of
isobutylaldehyde with sulfur monochloride according to the proce-
dure reported by Baidoo (1988). The reaction was exothermic, so
external cooling to keep the temperature below 298 K was needed.
The resulting yellow solid was separated and washed successively
with cold methanol and ether until the product became white. The
white solid was then dissolved in ethyl acetate and the solution
®ltered, yielding a clear solution. This solution was allowed to stand
at room temperature for a few days, whereupon crystals of (I)
suitable for X-ray structure analysis were formed (m.p. 437±438 K).
1H NMR (CDCl3): ꢁ C(CH3)2 1.34, 1.42, 2s, 12H; NCH2ÐCH2N
3.20, 3.23, 4.11, 4.14, 2d, 4H; N CH 6.84, s, 2H. 13C NMR (CDCl3): ꢁ
21.49, 24.67, 53.09, 61.53, 78.04. Analysis calculated for C10H18N2S2:
C 52.11, H 7.87, N 12.20, S 27.82%; found: C 51.95, H 8.31, N 12.18,
S 28.81%.
Crystal data
C10H18N2S2
Mr = 230.38
Orthorhombic, P212121
Ê
a = 8.7393 (9) A
Ê
b = 8.9284 (9) A
c = 15.9117 (17) A
Ê
V = 1241.6 (2) A
Mo Kꢂ radiation
Cell parameters from 8043
re¯ections
ꢃ = 2.6±28.2ꢀ
1
In (I), two symmetrical aliphatic units (Me2CÐC NÐC)
of nearly identical geometry are connected by an S1ÐS2 bond
Ê
[2.0201 (10) A], thus forming a four-atom-donor macrocycle
(Fig. 1). The S1ÐS2 bond length is slightly shorter than that in
ꢄ = 0.40 mm
T = 294 (2) K
Ê
3
Parallelepiped, colourless
0.28 Â 0.20 Â 0.15 mm
Z = 4
Dx = 1.233 Mg m
3
o276 # 2004 International Union of Crystallography
DOI: 10.1107/S0108270104004688
Acta Cryst. (2004). C60, o276±o277
Lo, Jem-Mau
