2-Amino-5-trifluoromethyl-1,3,4-thiadiazole and a redetermination of 2-amino-1,3,4-thiadiazole, both at 120 K: Chains of edge-fused R 22(8) and R44(10) rings, and sheets of R22(8) and R66(20) rings

Article abstract of DOI:10.1107/S0108270105040126

Molecules of 2-amino-5-trifluoromethyl-1,3,4-thiadiazole, C ₃H₂F₃N₃S, are linked by two independent N - H...N hydrogen bonds into sheets of alternating R ₂²(8) and R₆⁶(20) rings, while the molecules of the unsubstituted 2-amino-1,3,4-thiadiazole, C₂H ₃N₃S, are linked, again by two independent N - H...N hydrogen bonds, but into chains of edge-fused R₂²(8) and R₄⁴(10) rings.

Full text of DOI:10.1107/S0108270105040126

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
(
Lynch, 2001), and 5-amino-3-tri¯uoromethyl-1H-1,2,4-tria-
zole, (IV) (Borbulevych et al., 1998; Boechat et al., 2004).
Within the molecules of (I) and (II) (Figs. 1 and 2), the
corresponding bond distances (Table 1) are fairly similar, and
they show no real evidence for aromatic type ꢀ-electron
delocalization. In particular, the CÐS distances are all much
longer than such bonds in thiophenes (Allen et al., 1987). In
ISSN 0108-2701
2
-Amino-5-trifluoromethyl-1,3,4-thia-
ꢀ
each of (I) and (II), the CÐSÐC angle is less than 90 , with
diazole and a redetermination of
compensatory larger angles elsewhere in the rings (Table 1).
In each of (I) and (II), the amino groups act as double
donors in NÐHÁ Á ÁN hydrogen bonds (Tables 2 and 3).
However, in (I), the resulting supramolecular structure is one-
dimensional, while in (II) it is two-dimensional. In compound
(I), amino atom N2 in the molecule at (x, y, z) acts as
hydrogen-bond donor, via atoms H21 and H22, respectively, to
atoms N3 at (1 � x, 1 � y, 1 � z) and atom N4 at (x, y,
2
1
-amino-1,3,4-thiadiazole, both at
2
20 K: chains of edge-fused R (8) and
2
4
2
2
R (10) rings, and sheets of R (8) and
R (20) rings
4
6
6
a
b
Nubia Boechat, Sabrina B. Ferreira, Christopher
�
1 + z). Propagation by inversion and translation of these two
c
d
d
Glidewell, * John N. Low, Janet M. S. Skakle and
interactions generates a chain of edge-fused rings running
2
a
Solange M. S. V. Wardell
parallel to the [001] direction, with R (8) (Bernstein et al.,
2
1
1
1
a
1995) rings centred at ( , , n + ) (n = zero or integer) and
2 2 2
Complexo Tecnol o gico de Medicamentos Farmanguinhos, Avenida Comandante
4
1 1
b
R (10) rings centred at ( , , n) (n = zero or integer) (Fig. 3).
4
2 2
Guaranys 47, Jacarepagu a , Rio de Janeiro, RJ, Brazil, Departamento de Qu Âõ mica
Org aà nica, Instituto de Qu Âõ mica, Universidade Federal do Rio de Janeiro, CEP 21945-
The molecules of compound (II) are also linked into
2
c
9
70, Rio de Janeiro, RJ, Brazil, School of Chemistry, University of St Andrews, Fife
centrosymmetric R (8) dimers (Fig. 4) by paired NÐHÁ Á ÁN
2
d
KY16 9ST, Scotland, and Department of Chemistry, University of Aberdeen, Meston
Walk, Old Aberdeen AB24 3UE, Scotland
hydrogen bonds (Table 3), exactly the same as those in
compound (I). However, the further linking of these dimers
generates a (100) sheet, rather than an [001] chain. Amino
atoms N2 in the molecules at (x, y, z) and (1 � x, 1 � y, 1 � z),
Correspondence e-mail: cg@st-andrews.ac.uk
Received 30 November 2005
Accepted 1 December 2005
Online 24 December 2005
2
2
1
2
1
2
1
2
components of the R (8) dimer centred at ( , , ), act as
hydrogen-bond donors, via atom H21, to ring atoms N4 in
1
1
1
1
the molecules at (x, 2 � y, 2 + z) and (1 � x, 2 + y, 2 � z),
2
2
Molecules of 2-amino-5-tri¯uoromethyl-1,3,4-thiadiazole,
C H F N S, are linked by two independent NÐHÁ Á ÁN
respectively, which are components of the R (8) dimers
1
1
3
2
3
3
centred at ( , 0, 1) and ( , 1, 0), respectively. Similarly, atoms
2 2
2
2
6
6
hydrogen bonds into sheets of alternating R (8) and R (20)
rings, while the molecules of the unsubstituted 2-amino-1,3,4-
thiadiazole, C H N S, are linked, again by two independent
N4 in the molecules at (x, y, z) and (1 � x, 1 � y, 1 � z) accept
1
2
hydrogen bonds from atom N2 in the molecules at (x, � y,
2
3
3
NÐHÁ Á ÁN hydrogen bonds, but into chains of edge-fused
2
2
4
4
R (8) and R (10) rings.
Comment
The structure of 2-amino-1,3,4-thiadiazole, (I), was reported
several years ago (Khusenov et al., 1997). The use of room-
temperature diffraction data gave a ®nal R value of 0.079, but
no H-atom coordinates were reported, so that it is not possible
fully to analyse the supramolecular aggregation. We have now
reinvestigated this compound using diffraction data collected
Figure 1
The molecule of compound (I), showing the atom-labelling scheme.
Displacement ellipsoids are drawn at the 30% probability level.
at 120 K, together with the substituted analogue 2-amino-5-
tri¯uoromethyl-1,3,4-thiadiazole, (II), which is itself closely
related to both 2-amino-5-methyl-1,3,4-thiadiazole, (III)
Figure 2
The molecule of compound (II), showing the atom-labelling scheme.
Displacement ellipsoids are drawn at the 30% probability level.
o42 # 2006 International Union of Crystallography
DOI: 10.1107/S0108270105040126
Acta Cryst. (2006). C62, o42±o44

organic compounds
Figure 5
A stereoview of part of the crystal structure of compound (II), showing
2
2
6
6
the formation of a (100) sheet of alternating R (8) and R (20) rings.
differ from that in the related triazole, compound (IV), where
only two of the three available NÐH bonds participate in the
2
2
aggregation to form a C(4)C(5)[R (7)] chain of rings (Boechat
et al., 2004). However, compounds (II) and (III) are nearly
isostructural, when due account is taken of the space-group
settings employed, P2 /c for compound (II) reported here and
1
P2 /n for (III) reported by Lynch (2001). Both compounds
1
2
6
Figure 3
Part of the crystal structure of compound (I), showing the formation of an
form sheets of alternating R (8) and R (20) rings, so that the
2
6
description of the supramolecular aggregation in (III) as
three-dimensional (Lynch, 2001) is, in fact, incorrect.
2
4
[
001] chain of edge-fused R (8) and R (10) rings. For the sake of clarity,
2 4
the H atom bonded to atom C5 has been omitted. Atoms marked with
an asterisk (*), a hash (#), a dollar sign ($), an ampersand (&) or an `at'
sign (@) are at the symmetry positions (1 � x, 1 � y, 1 � z), (x, y,
Experimental
�
1 + z), (1 � x, 1 � y, � z), (x, y, 1 + z) and (1 � x, 1 � y, 2 � z),
respectively.
To a mixture of equimolar quantities (75 mmol of each) of the thio-
semicarbazide H
RCO H (R = H or CF
at ambient temperature. The reaction mixtures were then heated at
73 K for 7±10 h with stirring, cooled, poured onto ice±water and
2
NCSNHNH
2
and the appropriate carboxylic acid
2
3
), sulfuric acid (49 mmol) was added dropwise
3
rendered alkaline with aqueous sodium hydroxide solution. The
resulting solid products were collected by ®ltration, washed with
water, dried and recrystallized from ethanol, to yield crystals of
compounds (I) and (II) suitable for single-crystal X-ray diffraction.
1
Analysis for (I): 10 h reaction, 74% yield, m.p. 464±465 K; H NMR
1
3
(
(
(
MeOD): ꢁ 7.06 (s, 1H), 8.54 (s, 2H, NH
2
); C NMR (MeOD): ꢁ 144.8
C1), 171.2 (C2); IR (KBr, ꢂ, cm ): 3286 and 3091 (NÐH), 1618
N), 1509 (NH ), 1021 (C S). Analysis for (II): 7 h reaction,
5% yield, m.p. 489±491 K; H NMR (MeOD): ꢁ 7.71 (s, NH C
�
1
C
2
1
13
8
2
);
NMR (MeOD: ꢁ 121.1 (q, CF
3
, J = 269 Hz), 146.8 (q, C2, J = 38 Hz),
� 1
19
173.8 (C1); F NMR (MeOD): ꢁ � 61.45 (CF
3
); IR (KBr, ꢂ, cm ):
3303 and 3127 (NÐH), 1640 (C N), 1519 (NH
2
), 1075 (C S), 1193
3
and 745 (CF ).
Table 1
Selected geometric parameters (A, ) for compounds (I) and (II).
Ê
ꢀ
Figure 4
Part of the crystal structure of compound (II), showing the formation of a
(
I)
(II)
2
centrosymmetric R (8) dimer. Atoms marked with an asterisk (*) are at
the symmetry position (1 � x, 1 � y, 1 � z).
2
S1ÐC2
C2ÐN3
N3ÐN4
N4ÐC5
C5ÐS1
C2ÐN2
C5ÐC51
1.745 (2)
1.323 (2)
1.390 (2)
1.293 (3)
1.735 (2)
1.345 (3)
1.749 (2)
1.328 (3)
1.378 (3)
1.291 (3)
1.727 (2)
1.325 (3)
1.494 (4)
1
2
1
2
3
2
�
+ z) and (1 � x, + y, � z), respectively, which are
1
2
themselves components of the dimers centred at ( , 0, 0) and
1
(
, 1, 1). Propagation of these two hydrogen bonds then
generates a (100) sheet in the form of a (6,3)-net (Batten &
2
C5ÐS1ÐC2
S1ÐC2ÐN3
C2ÐN3ÐN4
N3ÐN4ÐC5
N4ÐC5ÐS1
S1ÐC2ÐN2
N3ÐC2ÐN2
86.59 (10)
113.86 (15)
111.73 (16)
113.04 (16)
114.78 (16)
121.89 (14)
124.25 (19)
86.31 (11)
113.56 (18)
111.81 (19)
113.03 (19)
115.29 (19)
122.35 (17)
124.1 (2)
2
6
6
Robson, 1998) built from alternating R (8) and R (20) rings
2
(
(
Fig. 5).
Thus, the modes of supramolecular aggregation in (I) and
II) are entirely different from one another. In addition, they
ꢁ
Acta Cryst. (2006). C62, o42±o44
Boechat et al.
2 3 3 3 2
C H N S and C H F
3 3
N S
o43

organic compounds
Compound (I)
Table 3
Hydrogen-bond geometry (A, ) for (II).
Ê
ꢀ
Crystal data
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C
M
2
H
3
N
3
S
Mo Kꢄ radiation
Cell parameters from 936
re¯ections
r
= 101.13
i
N2ÐH21Á Á ÁN3
0.84
0.87
2.16
2.10
2.985 (3)
2.959 (3)
171
169
Monoclinic, P2 =n
ii
1
N2ÐH22Á Á ÁN4
Ê
a = 5.5718 (5) A
ꢀ
ꢅ = 3.0±27.6
ꢆ = 0.60 mm
T = 120 (2) K
Ê
b = 13.4573 (17) A
� 1
Symmetry codes: (i) � x ‡ 1; � y ‡ 1; � z ‡ 1; (ii) x; � y ‡
1
2
; z ‡
1
.
2
Ê
c = 5.7875 (5) A
ꢀ
Ê
ꢃ = 109.984 (6)
V = 407.83 (7) A
Z = 4
Needle, colourless
0.15 Â 0.04 Â 0.02 mm
3
1 1
The space groups P2 /n and P2 /c for compounds (I) and (II),
�
3
respectively, were uniquely assigned from the systematic absences.
All H atoms were located in difference maps. The coordinates of the
H atom bonded to carbon in compound (I) were freely re®ned, giving
D
x
= 1.647 Mg m
Data collection
Ê
a CÐH distance of 0.95 (3) A. H atoms bonded to nitrogen were
Nonius KappaCCD area-detector
diffractometer
936 independent re¯ections
736 re¯ections with I > 2ꢇ(I)
allowed to ride at the positions found from the difference maps, with
U
'
and ! scans
Absorption correction: multi-scan
SADABS; Sheldrick, 2003)
min = 0.919, Tmax = 0.988
842 measured re¯ections
Rint = 0.096
iso(H) = 1.2Ueq(N); the resulting NÐH distances were in the range
ꢀ
ꢅ
max = 27.6
Ê
.84±0.89 A. In (II), the anisotropic displacement parameters for the
0
(
T
h = � 7 ! 7
k = � 17 ! 17
l = � 6 ! 7
F atoms suggest that there may be some libration of the CF
about the C5ÐC51 bond.
3
group
6
For both compounds, data collection: COLLECT (Nonius, 1999);
cell re®nement: DENZO (Otwinowski Minor, 1997) and
Re®nement
&
2
Re®nement on F
2
H-atom parameters constrained
2
2
2
o
2
COLLECT; data reduction: DENZO and COLLECT; program(s)
used to solve structure: WinGX (Farrugia, 1999) and SIR92 (Alto-
mare et al., 1993); program(s) used to re®ne structure: OSCAIL
R[F > 2ꢇ(F )] = 0.038
wR(F ) = 0.102
S = 1.08
w = 1/[ꢇ (F
where P = (F
(Á/ꢇ)max = 0.001
) + (0.056P) ]
2
2 2
o c
+ 2F )/3
Ê
� 3
9
5
36 re¯ections
9 parameters
Áꢈmax = 0.39 e A
Áꢈmin = � 0.38 e AÊ
(McArdle, 2003) and SHELXL97 (Sheldrick, 1997); molecular
� 3
graphics: PLATON (Spek, 2003); software used to prepare material
for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).
Table 2
Hydrogen-bond geometry (A, ) for (I).
Ê
ꢀ
The X-ray data were collected at the EPSRC X-ray Crys-
tallographic Service, University of Southampton, England; the
authors thank the staff for all their help and advice. SMSVW
thanks CNPq and FAPERJ for ®nancial support.
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
i
N2ÐH21Á Á ÁN3
0.87
0.89
2.13
2.08
2.999 (3)
2.969 (2)
175
172
ii
N2ÐH22Á Á ÁN4
Symmetry codes: (i) � x ‡ 1; � y ‡ 1; � z ‡ 1; (ii) x; y; z � 1.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SK1892). Services for accessing these data are
described at the back of the journal.
Compound (II)
Crystal data
References
C
3
2 3
H F N
3
S
Mo Kꢄ radiation
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor,
R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1±19.
Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl.
Cryst. 26, 343±350.
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Int. Ed. Engl. 34, 1555±1573.
Boechat, N., Dutra, K. D. B., Valverde, A. L., Wardell, S. M. S. V., Low, J. N. &
Glidewell, C. (2004). Acta Cryst. C60, o733±o736.
Borbulevych, O. Y., Shishkin, O. V., Desenko, S. M., Chernenko, V. N. & Orlov,
V. D. (1998). Acta Cryst. C54, 442±444.
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837±838.
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Khusenov, K. S., Umarov, B. B., Ishankhodzhaeva, M. M., Parpiev, N. A.,
Talipov, S. A. & Ibragimov, B. T. (1997). Russ. J. Coord. Chem. 23, 555±559;
Chem. Abstr. 127, 302376x.
M
r
= 169.14
Cell parameters from 1386
re¯ections
Monoclinic, P2 =c
1
Ê
ꢀ
a = 9.1082 (12) A
ꢅ = 3.6±27.5
ꢆ = 0.51 mm
T = 120 (2) K
Ê
b = 6.9373 (10) A
� 1
Ê
c = 10.8048 (14) A
ꢀ
ꢃ = 116.656 (9)
V = 610.15 (14) A
Z = 4
Plate, colourless
0.32 Â 0.24 Â 0.06 mm
Ê
3
�
3
D
x
= 1.841 Mg m
Data collection
Nonius KappaCCD area-detector
diffractometer
1386 independent re¯ections
1093 re¯ections with I > 2ꢇ(I)
'
and ! scans
Absorption correction: multi-scan
SADABS; Sheldrick, 2003)
min = 0.853, Tmax = 0.970
231 measured re¯ections
Rint = 0.044
ꢀ
ꢅ
max = 27.5
(
h = � 11 ! 11
Lynch, D. E. (2001). Acta Cryst. C57, 1201±1203.
T
k = � 9 ! 9
McArdle, P. (2003). OSCAIL for Windows. Version 10. Crystallography
Centre, Chemistry Department, NUI Galway, Ireland.
Nonius (1999). COLLECT. Nonius BV, Delft, The Netherlands.
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276,
Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M.
Sweet, pp. 307±326. New York: Academic Press.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
G oÈ ttingen, Germany.
Sheldrick, G. M. (2003). SADABS. Version 2.10. University of G oÈ ttingen,
Germany.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7±13.
6
l = � 14 ! 13
Re®nement
2
2
2
2
Re®nement on F
2
R[F > 2ꢇ(F )] = 0.045
wR(F ) = 0.113
S = 1.10
o
w = 1/[ꢇ (F ) + (0.0491P)
2
+ 0.4024P]
where P = (F
2
2
2
c
o
+ 2F
)/3
(Á/ꢇ)max < 0.001
Ê
� 3
� 3
1
9
386 re¯ections
1 parameters
Áꢈmax = 0.33 e A
Áꢈmin = � 0.35 e AÊ
H-atom parameters constrained
ꢁ
o44 Boechat et al.
2 3
C H N
3 3
S and C H
F N
2 3 3
S
Acta Cryst. (2006). C62, o42±o44