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 R22(8) and R44(10) rings, and sheets of R22(8) and R66(20) rings

Boechat, N.; Ferreira, S.B.; Glidewell, C.; Low, J.N.; Skakle, J.M.S.; Wardell, S.M.S.V.

doi:10.1107/S0108270105040126

organic compounds

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 62| Part 1| January 2006| Pages o42-o44

doi:10.1107/S0108270105040126

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 R₂²(8) and R₄⁴(10) rings, and sheets of R₂²(8) and R₆⁶(20) rings

Nubia Boechat,^a Sabrina B. Ferreira,^b Christopher Glidewell,^c ^* John N. Low,^d Janet M. S. Skakle ^d and Solange M. S. V. Wardell ^a

^aComplexo Tecnológico de Medicamentos Farmanguinhos, Avenida Comandante Guaranys 47, Jacarepaguá, Rio de Janeiro, RJ, Brazil, ^bDepartamento de Química Orgânica, Instituto de Química, Universidade Federal do Rio de Janeiro, CEP 21945-970, Rio de Janeiro, RJ, Brazil, ^cSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland, and ^dDepartment of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland
^*Correspondence e-mail: cg@st-andrews.ac.uk

(Received 30 November 2005; accepted 1 December 2005; online 24 December 2005)

Molecules of 2-amino-5-trifluoromethyl-1,3,4-thiadiazole, C₃H₂F₃N₃S, are linked by two independent N—H⋯N hydrogen bonds into sheets of alternating R₂²(8) and R₆⁶(20) rings, while the molecules of the unsubstituted 2-amino-1,3,4-thiadiazole, C₂H₃N₃S, are linked, again by two independent N—H⋯N hydrogen bonds, but into chains of edge-fused R₂²(8) and R₄⁴(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 final 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

at 120 K, together with the substituted analogue 2-amino-5-trifluoromethyl-1,3,4-thiadiazole, (II)

, which is itself closely related to both 2-amino-5-methyl-1,3,4-thiadiazole, (III)

(Lynch, 2001

), and 5-amino-3-trifluoromethyl-1H-1,2,4-triazole, (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 π-electron delocalization. In particular, the C—S distances are all much longer than such bonds in thiophenes (Allen et al., 1987 ). In each of (I) and (II), the C—S—C angle is less than 90°, with compensatory larger angles elsewhere in the rings (Table 1).

In each of (I) and (II), the amino groups act as double donors in N—H⋯N 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, −1 + z). Propagation by inversion and translation of these two interactions generates a chain of edge-fused rings running parallel to the [001] direction, with R₂²(8) (Bernstein et al., 1995 ) rings centred at ( $[{1 \over 2}]$ , $[{1 \over 2}]$ , n + $[{1 \over 2}]$ ) (n = zero or integer) and R₄⁴(10) rings centred at ( $[{1 \over 2}]$ , $[{1 \over 2}]$ , n) (n = zero or integer) (Fig. 3).

The molecules of compound (II) are also linked into centrosymmetric R₂²(8) dimers (Fig. 4) by paired N—H⋯N 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), components of the R₂²(8) dimer centred at ( $[{1\over 2}]$ , $[{1\over 2}]$ , $[{1\over 2}]$ ), act as hydrogen-bond donors, via atom H21, to ring atoms N4 in the molecules at (x, $[{1\over 2}]$ − y, $[{1\over 2}]$ + z) and (1 − x, $[{1\over 2}]$ + y, $[{1\over 2}]$ − z), respectively, which are components of the R₂²(8) dimers centred at ( $[{1\over 2}]$ , 0, 1) and ( $[{1\over 2}]$ , 1, 0), respectively. Similarly, atoms N4 in the molecules at (x, y, z) and (1 − x, 1 − y, 1 − z) accept hydrogen bonds from atom N2 in the molecules at (x, $[{1\over 2}]$ − y, − $[{1\over 2}]$ + z) and (1 − x, $[{1\over 2}]$ + y, $[{3\over 2}]$ − z), respectively, which are themselves components of the dimers centred at ( $[{1\over 2}]$ , 0, 0) and ( $[{1\over 2}]$ , 1, 1). Propagation of these two hydrogen bonds then generates a (100) sheet in the form of a (6,3)-net (Batten & Robson, 1998 ) built from alternating R₂²(8) and R₆⁶(20) rings (Fig. 5).

Thus, the modes of supramolecular aggregation in (I) and (II) are entirely different from one another. In addition, they differ from that in the related triazole, compound (IV), where only two of the three available N—H bonds participate in the aggregation to form a C(4)C(5)[R₂²(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, P2₁/c for compound (II) reported here and P2₁/n for (III) reported by Lynch (2001). Both compounds form sheets of alternating R₂²(8) and R₆⁶(20) rings, so that the description of the supramolecular aggregation in (III) as three-dimensional (Lynch, 2001) is, in fact, incorrect.

Figure 1
The molecule of compound (I)

, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
The molecule of compound (II)

, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 3
Part of the crystal structure of compound (I)

, showing the formation of an [001] chain of edge-fused R₂²(8) and R₄⁴(10) rings. For the sake of clarity, 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, −1 + z), (1 − x, 1 − y, −z), (x, y, 1 + z) and (1 − x, 1 − y, 2 − z), respectively.

Figure 4
Part of the crystal structure of compound (II)

, showing the formation of a centrosymmetric R₂²(8) dimer. Atoms marked with an asterisk (*) are at the symmetry position (1 − x, 1 − y, 1 − z).

Figure 5
A stereoview of part of the crystal structure of compound (II)

, showing the formation of a (100) sheet of alternating R₂²(8) and R₆⁶(20) rings.

Experimental

To a mixture of equimolar quantities (75 mmol of each) of the thiosemicarbazide H₂NCSNHNH₂ and the appropriate carboxylic acid RCO₂H (R = H or CF₃), sulfuric acid (49 mmol) was added dropwise at ambient temperature. The reaction mixtures were then heated at 373 K for 7–10 h with stirring, cooled, poured onto ice–water and rendered alkaline with aqueous sodium hydroxide solution. The resulting solid products were collected by filtration, washed with water, dried and recrystallized from ethanol, to yield crystals of compounds (I) and (II) suitable for single-crystal X-ray diffraction. Analysis for (I): 10 h reaction, 74% yield, m.p. 464–465 K; ¹H NMR (MeOD): δ 7.06 (s, 1H), 8.54 (s, 2H, NH₂); ¹³C NMR (MeOD): δ 144.8 (C1), 171.2 (C2); IR (KBr, ν, cm⁻¹): 3286 and 3091 (N—H), 1618 (C=N), 1509 (NH₂), 1021 (C=S). Analysis for (II): 7 h reaction, 85% yield, m.p. 489–491 K; ¹H NMR (MeOD): δ 7.71 (s, NH₂); ¹³C NMR (MeOD: δ 121.1 (q, CF₃, J = 269 Hz), 146.8 (q, C2, J = 38 Hz), 173.8 (C1); ¹⁹F NMR (MeOD): δ −61.45 (CF₃); IR (KBr, ν, cm⁻¹): 3303 and 3127 (N—H), 1640 (C=N), 1519 (NH₂), 1075 (C=S), 1193 and 745 (CF₃).

Compound (I)

Crystal data

C₂H₃N₃S
M_r = 101.13
Monoclinic, P 2₁ /n
a = 5.5718 (5) Å
b = 13.4573 (17) Å
c = 5.7875 (5) Å
β = 109.984 (6)°
V = 407.83 (7) Å³
Z = 4
D_x = 1.647 Mg m⁻³
Mo Kα radiation
Cell parameters from 936 reflections
θ = 3.0–27.6°
μ = 0.60 mm⁻¹
T = 120 (2) K
Needle, colourless
0.15 × 0.04 × 0.02 mm

Data collection

Nonius KappaCCD area-detector diffractometer
φ and ω scans
Absorption correction: multi-scan(SADABS; Sheldrick, 2003 )T_min = 0.919, T_max = 0.988
6842 measured reflections
936 independent reflections
736 reflections with I > 2σ(I)
R_int = 0.096
θ_max = 27.6°
h = −7 → 7
k = −17 → 17
l = −6 → 7

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.038
wR(F²) = 0.102
S = 1.08
936 reflections
59 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.056P)²] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max = 0.001
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Table 1
Selected geometric parameters (Å, °) for compounds (I) and (II)

	(I)	(II)
S1—C2	1.745 (2)	1.749 (2)
C2—N3	1.323 (2)	1.328 (3)
N3—N4	1.390 (2)	1.378 (3)
N4—C5	1.293 (3)	1.291 (3)
C5—S1	1.735 (2)	1.727 (2)
C2—N2	1.345 (3)	1.325 (3)
C5—C51		1.494 (4)

C5—S1—C2	86.59 (10)	86.31 (11)
S1—C2—N3	113.86 (15)	113.56 (18)
C2—N3—N4	111.73 (16)	111.81 (19)
N3—N4—C5	113.04 (16)	113.03 (19)
N4—C5—S1	114.78 (16)	115.29 (19)
S1—C2—N2	121.89 (14)	122.35 (17)
N3—C2—N2	124.25 (19)	124.1 (2)

Compound (II)

Crystal data

C₃H₂F₃N₃S
M_r = 169.14
Monoclinic, P 2₁ /c
a = 9.1082 (12) Å
b = 6.9373 (10) Å
c = 10.8048 (14) Å
β = 116.656 (9)°
V = 610.15 (14) Å³
Z = 4
D_x = 1.841 Mg m⁻³
Mo Kα radiation
Cell parameters from 1386 reflections
θ = 3.6–27.5°
μ = 0.51 mm⁻¹
T = 120 (2) K
Plate, colourless
0.32 × 0.24 × 0.06 mm

Data collection

Nonius KappaCCD area-detector diffractometer
φ and ω scans
Absorption correction: multi-scan(SADABS; Sheldrick, 2003)T_min = 0.853, T_max = 0.970
6231 measured reflections
1386 independent reflections
1093 reflections with I > 2σ(I)
R_int = 0.044
θ_max = 27.5°
h = −11 → 11
k = −9 → 9
l = −14 → 13

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.045
wR(F²) = 0.113
S = 1.10
1386 reflections
91 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.0491P)² + 0.4024P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Table 2
Hydrogen-bond geometry (Å, °) for (I)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H21⋯N3ⁱ	0.87	2.13	2.999 (3)	175
N2—H22⋯N4ⁱⁱ	0.89	2.08	2.969 (2)	172
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) x, y, z-1.

Table 3
Hydrogen-bond geometry (Å, °) for (II)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H21⋯N3ⁱ	0.84	2.16	2.985 (3)	171
N2—H22⋯N4ⁱⁱ	0.87	2.10	2.959 (3)	169
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

The space groups P2₁/n and P2₁/c for compounds (I) and (II), 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 refined, giving a C—H distance of 0.95 (3) Å. H atoms bonded to nitrogen were allowed to ride at the positions found from the difference maps, with U_iso(H) = 1.2U_eq(N); the resulting N—H distances were in the range 0.84–0.89 Å. In (II), the anisotropic displacement parameters for the F atoms suggest that there may be some libration of the CF₃ group about the C5—C51 bond.

For both compounds, data collection: COLLECT (Nonius, 1999 ); cell refinement: DENZO (Otwinowski & Minor, 1997 ) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: WinGX (Farrugia, 1999 ) and SIR92 (Altomare et al., 1993 ); program(s) used to refine structure: OSCAIL (McArdle, 2003 ) and SHELXL97 (Sheldrick, 1997 ); molecular graphics: PLATON (Spek, 2003 ); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I, II. DOI: 10.1107/S0108270105040126/sk1892sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S0108270105040126/sk1892Isup2.hkl

Structure factors: contains datablock II. DOI: 10.1107/S0108270105040126/sk1892IIsup3.hkl

Comment top

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 final R 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 at 120 K, together with the substituted analogue 2-amino-5-trifluoromethyl-1,3,4-thiadiazole, (II), which is itself closely related to both 2-amino-5-methyl-1,3,4-thiadiazole, (III) (Lynch, 2001), and 5-amino-3-trifluoromethyl-1H-1,2,4-triazole, (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 π-electron delocalization. In particular, the C—S distances are all much longer than such bonds in thiophenes (Allen et al., 1987). In each of (I) and (II), the C—S—C angle is less than 90°, with compensatory larger angles elsewhere in the rings (Table 1).

In each of (I) and (II), the amino groups act as double donors in N—H···N 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), the amino atom N2 in the molecule at (x, y, z) acts as hydrogen-bond donor, via atoms H21 and H22, respectively, to atoms N at (1 - x, 1 - y, 1 - z) and atom N4 at (x, y, -1 + z). Propagation by inversion and translation of these two interactions generates a chain of edge-fused rings running parallel to the [001] direction, with R₂²(8) (Bernstein et al., 1995) rings centred at (1/2, 1/2, n + 1/2) (n = zero or integer) and R₄⁴(10) rings centred at (1/2, 1/2, n) (n = zero or integer) (Fig. 3).

The molecules of compound (II) are also linked into centrosymmetric R₂²(8) dimers (Fig. 4) by paired N—H···N 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. The amino atoms N2 in the molecules at (x, y, z) and (1 - x, 1 - y, 1 - z), components of the R²₂(8) dimer centred at (1/2, 1/2, 1/2), act as hydrogen-bond donors, via atom H21, to the ring atoms N4 in the molecules at (x, 1/2 - y, 1/2 + z) and (1 - x, 1/2 + y, 1/2 - z), respectively, which are components of the R²₂(8) dimers centred at (1/2, 0, 1) and (1/2, 1, 0), respectively. Similarly, atoms N4 in the molecules at (x, y, z) and (1 - x, 1 - y, 1 - z) accept hydrogen bonds from atom N2 in the molecules at (x, 1/2 - y, -1/2 + z) and (1 - x, 1/2 + y, 3/2 - z), respectively, which are themselves components of the dimers centred at (1/2, 0, 0) and (1/2, 1, 1). Propagation of these two hydrogen bonds then generates a (100) sheet in the form of a (6,3) net (Batten & Robson, 1998) built from alternating R²₂(8) and R⁶₆(20) rings (Fig. 5).

Thus, the modes of supramolecular aggregation in (I) and (II) are entirely different from one another. In addition, they differ from that in the related triazole, compound (IV), where only two of the three available N—H bonds participate in the aggregation to form a C(4)C(5)[R²₂(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, P2₁/c for compound (I) [(II)?] reported here and P2₁/n for (III) reported by Lynch (2001). Both compounds form sheets of alternating R²₂(8) and R⁶₆(20) rings, so that the description of the supramolecular aggregation in (III) as three-dimensional (Lynch, 2001) is, in fact, incorrect.

Experimental top

To a mixture of equimolar quantities (75 mmol of each) of the thiosemicarbazide H₂NCSNHNH₂ and the appropriate carboxylic acid RCO₂H (R = H or CF₃), sulfuric acid (49 mmol) was added dropwise at ambient temperature. The reaction mixtures were then heated at 373 K for 7–10 h with stirring, cooled, poured onto ice–water and rendered alkaline with aqueous sodium hydroxide solution. The resulting solid products were collected by filtration, washed with water, dried and recrystallized from ethanol, to yield crystals of compounds (I) and (II) suitable for single-crystal X-ray diffraction. Analysis for (I): 10 h reaction, 74% yield, m.p. 464–465 K; ¹H NMR (MeOD, δ, p.p.m.): 7.06 (s, 1H), 8.54 (s, 2H, NH₂); ¹³C NMR (MeOD, δ, p.p.m.): 144.8 (C1), 171.2 (C2); IR (KBr, ν, cm^-1): 3286 and 3091 (N—H), 1618 (C═N), 1509 (NH₂), 1021 (C═S). Analysis for (II): 7 h reaction, 85% yield, m.p. 489–491 K; ¹H NMR (MeOD, δ, p.p.m.): 7.71 (s, NH₂); ¹³C NMR (MeOD, δ, p.p.m.): 121.1 (q, CF₃, J = 269 Hz), 146.8 (q, C2, J = 38 Hz), 173.8 (C1); ¹⁹F NMR (MeOD, δ, p.p.m.): -61.45 (CF₃); IR (KBr, ν, cm^-1): 3303 and 3127 (N—H), 1640 (C═N), 1519 (NH₂), 1075 (C═S), 1193 and 745 (CF₃).

Structure description top

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 π-electron delocalization. In particular, the C—S distances are all much longer than such bonds in thiophenes (Allen et al., 1987). In each of (I) and (II), the C—S—C angle is less than 90°, with compensatory larger angles elsewhere in the rings (Table 1).

Thus, the modes of supramolecular aggregation in (I) and (II) are entirely different from one another. In addition, they differ from that in the related triazole, compound (IV), where only two of the three available N—H bonds participate in the aggregation to form a C(4)C(5)[R²₂(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, P2₁/c for compound (I) [(II)?] reported here and P2₁/n for (III) reported by Lynch (2001). Both compounds form sheets of alternating R²₂(8) and R⁶₆(20) rings, so that the description of the supramolecular aggregation in (III) as three-dimensional (Lynch, 2001) is, in fact, incorrect.

Computing details top

For both compounds, data collection: COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: WinGX (Farrugia, 1999) and SIR92 (Altomare et al., 1993); program(s) used to refine structure: OSCAIL (McArdle, 2003) and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures top

	Fig. 1. The molecule of compound (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. The molecule of compound (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 3. Part of the crystal structure of compound (I), showing the formation of an [001] chain of edge-fused R²₂(8) and R⁴₄(10) rings. For the sake of clarity, the H atom bonded to atom C5 has been omitted. The 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, -1 + z), (1 - x, 1 - y, -z), (x, y, 1 + z) and (1 - x, 1 - y, 2 - z), respectively.
	Fig. 4. Part of the crystal structure of compound (II), showing the formation of a centrosymmetric R²₂(8) dimer. The atoms marked with an asterisk (*) are at the symmetry position (1 - x, 1 - y, 1 - z).
	Fig. 5. A stereoview of part of the crystal structure of compound (II), showing the formation of a (100) sheet of alternating R²₂(8) and R⁶₆(20) rings.

(I) 2-amino-1,3,4-thiadiazole top

Crystal data top

C₂H₃N₃S	F(000) = 208
M_r = 101.13	D_x = 1.647 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 936 reflections
a = 5.5718 (5) Å	θ = 3.0–27.6°
b = 13.4573 (17) Å	µ = 0.60 mm⁻¹
c = 5.7875 (5) Å	T = 120 K
β = 109.984 (6)°	Needle, colourless
V = 407.83 (7) Å³	0.15 × 0.04 × 0.02 mm
Z = 4

Data collection top

Nonius KappaCCD area-detector diffractometer	936 independent reflections
Radiation source: Bruker Nonius FR91 rotating anode	736 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.096
Detector resolution: 9.091 pixels mm^-1	θ_max = 27.6°, θ_min = 3.0°
φ and ω scans	h = −7→7
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −17→17
T_min = 0.919, T_max = 0.988	l = −6→7
6842 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.102	H-atom parameters constrained
S = 1.08	w = 1/[σ²(F_o²) + (0.056P)²] where P = (F_o² + 2F_c²)/3
936 reflections	(Δ/σ)_max = 0.001
59 parameters	Δρ_max = 0.39 e Å⁻³
0 restraints	Δρ_min = −0.38 e Å⁻³

Crystal data top

C₂H₃N₃S	V = 407.83 (7) Å³
M_r = 101.13	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 5.5718 (5) Å	µ = 0.60 mm⁻¹
b = 13.4573 (17) Å	T = 120 K
c = 5.7875 (5) Å	0.15 × 0.04 × 0.02 mm
β = 109.984 (6)°

Data collection top

Nonius KappaCCD area-detector diffractometer	936 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	736 reflections with I > 2σ(I)
T_min = 0.919, T_max = 0.988	R_int = 0.096
6842 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.038	0 restraints
wR(F²) = 0.102	H-atom parameters constrained
S = 1.08	Δρ_max = 0.39 e Å⁻³
936 reflections	Δρ_min = −0.38 e Å⁻³
59 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	−0.09495 (9)	0.66383 (5)	0.20459 (8)	0.0231 (2)
N2	0.3077 (3)	0.55639 (16)	0.1828 (3)	0.0265 (5)
N3	0.2533 (3)	0.57916 (15)	0.5659 (3)	0.0207 (4)
N4	0.0865 (3)	0.62459 (16)	0.6651 (3)	0.0225 (5)
C2	0.1817 (3)	0.59265 (18)	0.3254 (3)	0.0192 (5)
C5	−0.0989 (4)	0.67071 (19)	0.5026 (4)	0.0231 (5)
H21	0.4382	0.5178	0.2485	0.032*
H22	0.2423	0.5705	0.0231	0.032*
H5	−0.229 (4)	0.709 (2)	0.531 (4)	0.033 (6)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0227 (3)	0.0278 (4)	0.0179 (3)	0.0044 (2)	0.0057 (2)	0.0033 (2)
N2	0.0253 (8)	0.0391 (15)	0.0153 (8)	0.0089 (8)	0.0073 (6)	0.0045 (8)
N3	0.0229 (8)	0.0224 (13)	0.0171 (7)	0.0007 (7)	0.0072 (6)	−0.0006 (7)
N4	0.0262 (9)	0.0229 (13)	0.0201 (8)	−0.0012 (8)	0.0099 (7)	−0.0023 (7)
C2	0.0204 (9)	0.0181 (13)	0.0181 (9)	−0.0012 (8)	0.0053 (7)	0.0020 (8)
C5	0.0253 (10)	0.0239 (15)	0.0219 (10)	0.0005 (9)	0.0104 (8)	−0.0006 (9)

Geometric parameters (Å, º) top

S1—C5	1.735 (2)	N2—H22	0.89
S1—C2	1.745 (2)	N3—N4	1.390 (2)
C2—N3	1.323 (2)	N4—C5	1.293 (3)
C2—N2	1.345 (3)	C5—H5	0.95 (3)
N2—H21	0.87

C5—S1—C2	86.59 (10)	H21—N2—H22	124.5
N3—C2—N2	124.25 (19)	C2—N3—N4	111.73 (16)
N3—C2—S1	113.86 (15)	C5—N4—N3	113.04 (16)
N2—C2—S1	121.89 (14)	N4—C5—S1	114.78 (16)
C2—N2—H21	118.9	N4—C5—H5	127.2 (13)
C2—N2—H22	116.4	S1—C5—H5	118.0 (14)

C5—S1—C2—N3	−0.45 (18)	C2—N3—N4—C5	−0.8 (3)
C5—S1—C2—N2	−180.0 (2)	N3—N4—C5—S1	0.4 (3)
N2—C2—N3—N4	−179.7 (2)	C2—S1—C5—N4	0.00 (19)
S1—C2—N3—N4	0.8 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···N3ⁱ	0.87	2.13	2.999 (3)	175
N2—H22···N4ⁱⁱ	0.89	2.08	2.969 (2)	172

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, y, z−1.

(II) 2-amino-5-trifluoromethyl-1,3,4-thiadiazole top

Crystal data top

C₃H₂F₃N₃S	F(000) = 336
M_r = 169.14	D_x = 1.841 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1386 reflections
a = 9.1082 (12) Å	θ = 3.6–27.5°
b = 6.9373 (10) Å	µ = 0.51 mm⁻¹
c = 10.8048 (14) Å	T = 120 K
β = 116.656 (9)°	Plate, colourless
V = 610.15 (14) Å³	0.32 × 0.24 × 0.06 mm
Z = 4

Data collection top

Nonius KappaCCD area-detector diffractometer	1386 independent reflections
Radiation source: Bruker Nonius FR91 rotating anode	1093 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.044
Detector resolution: 9.091 pixels mm^-1	θ_max = 27.5°, θ_min = 3.6°
φ and ω scans	h = −11→11
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −9→9
T_min = 0.853, T_max = 0.970	l = −14→13
6231 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.113	H-atom parameters constrained
S = 1.10	w = 1/[σ²(F_o²) + (0.0491P)² + 0.4024P] where P = (F_o² + 2F_c²)/3
1386 reflections	(Δ/σ)_max < 0.001
91 parameters	Δρ_max = 0.33 e Å⁻³
0 restraints	Δρ_min = −0.35 e Å⁻³

Crystal data top

C₃H₂F₃N₃S	V = 610.15 (14) Å³
M_r = 169.14	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.1082 (12) Å	µ = 0.51 mm⁻¹
b = 6.9373 (10) Å	T = 120 K
c = 10.8048 (14) Å	0.32 × 0.24 × 0.06 mm
β = 116.656 (9)°

Data collection top

Nonius KappaCCD area-detector diffractometer	1386 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	1093 reflections with I > 2σ(I)
T_min = 0.853, T_max = 0.970	R_int = 0.044
6231 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	0 restraints
wR(F²) = 0.113	H-atom parameters constrained
S = 1.10	Δρ_max = 0.33 e Å⁻³
1386 reflections	Δρ_min = −0.35 e Å⁻³
91 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	0.24020 (8)	0.10495 (9)	0.55838 (6)	0.0289 (2)
F1	0.2190 (2)	−0.2644 (3)	0.2778 (2)	0.0675 (6)
F2	−0.0036 (2)	−0.1325 (2)	0.25331 (19)	0.0535 (5)
F3	0.1382 (3)	−0.2906 (3)	0.43495 (19)	0.0639 (6)
N2	0.4169 (3)	0.4342 (3)	0.6332 (2)	0.0331 (5)
N3	0.3963 (2)	0.2678 (3)	0.43721 (19)	0.0281 (5)
N4	0.3250 (2)	0.1038 (3)	0.3623 (2)	0.0267 (5)
C2	0.3625 (3)	0.2894 (4)	0.5439 (2)	0.0258 (5)
C5	0.2433 (3)	0.0068 (4)	0.4127 (2)	0.0267 (5)
C51	0.1499 (3)	−0.1710 (4)	0.3435 (3)	0.0334 (6)
H21	0.4715	0.5235	0.6221	0.040*
H22	0.3911	0.4400	0.7012	0.040*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0330 (4)	0.0325 (4)	0.0262 (3)	−0.0023 (3)	0.0176 (3)	0.0003 (2)
F1	0.0644 (13)	0.0606 (12)	0.0989 (16)	−0.0210 (10)	0.0557 (12)	−0.0473 (12)
F2	0.0353 (9)	0.0412 (10)	0.0597 (11)	−0.0039 (8)	−0.0003 (9)	−0.0050 (8)
F3	0.0956 (16)	0.0394 (10)	0.0493 (10)	−0.0199 (10)	0.0260 (11)	0.0060 (8)
N2	0.0406 (13)	0.0399 (12)	0.0261 (10)	−0.0116 (10)	0.0213 (10)	−0.0075 (9)
N3	0.0321 (11)	0.0327 (11)	0.0224 (10)	−0.0026 (9)	0.0148 (9)	−0.0021 (8)
N4	0.0277 (11)	0.0296 (11)	0.0250 (10)	0.0016 (9)	0.0136 (9)	−0.0007 (8)
C2	0.0246 (12)	0.0314 (13)	0.0238 (11)	−0.0001 (10)	0.0132 (10)	0.0027 (9)
C5	0.0267 (12)	0.0284 (12)	0.0259 (11)	0.0040 (10)	0.0126 (10)	0.0019 (10)
C51	0.0356 (14)	0.0322 (13)	0.0349 (14)	0.0019 (11)	0.0180 (12)	−0.0007 (11)

Geometric parameters (Å, º) top

S1—C5	1.727 (2)	N3—N4	1.378 (3)
S1—C2	1.749 (2)	N4—C5	1.291 (3)
C2—N2	1.325 (3)	C5—C51	1.494 (4)
C2—N3	1.328 (3)	C51—F1	1.312 (3)
N2—H21	0.84	C51—F2	1.324 (3)
N2—H22	0.87	C51—F3	1.330 (3)

C5—S1—C2	86.31 (11)	N4—C5—C51	121.7 (2)
N2—C2—N3	124.1 (2)	N4—C5—S1	115.29 (19)
N2—C2—S1	122.35 (17)	C51—C5—S1	122.87 (18)
N3—C2—S1	113.56 (18)	F1—C51—F2	107.8 (2)
C2—N2—H21	120.7	F1—C51—F3	108.1 (2)
C2—N2—H22	119.8	F2—C51—F3	105.2 (2)
H21—N2—H22	119.4	F1—C51—C5	112.0 (2)
C2—N3—N4	111.81 (19)	F2—C51—C5	112.2 (2)
C5—N4—N3	113.03 (19)	F3—C51—C5	111.2 (2)

C5—S1—C2—N2	−179.1 (2)	C2—S1—C5—C51	−176.7 (2)
C5—S1—C2—N3	0.03 (18)	N4—C5—C51—F1	31.1 (3)
N2—C2—N3—N4	179.5 (2)	S1—C5—C51—F1	−152.8 (2)
S1—C2—N3—N4	0.4 (3)	N4—C5—C51—F2	−90.3 (3)
C2—N3—N4—C5	−0.7 (3)	S1—C5—C51—F2	85.8 (3)
N3—N4—C5—C51	177.1 (2)	N4—C5—C51—F3	152.2 (2)
N3—N4—C5—S1	0.7 (3)	S1—C5—C51—F3	−31.7 (3)
C2—S1—C5—N4	−0.45 (19)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···N3ⁱ	0.84	2.16	2.985 (3)	171
N2—H22···N4ⁱⁱ	0.87	2.10	2.959 (3)	169

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+1/2, z+1/2.

Experimental details

	(I)	(II)
Crystal data
Chemical formula	C₂H₃N₃S	C₃H₂F₃N₃S
M_r	101.13	169.14
Crystal system, space group	Monoclinic, P2₁/n	Monoclinic, P2₁/c
Temperature (K)	120	120
a, b, c (Å)	5.5718 (5), 13.4573 (17), 5.7875 (5)	9.1082 (12), 6.9373 (10), 10.8048 (14)
β (°)	109.984 (6)	116.656 (9)
V (Å³)	407.83 (7)	610.15 (14)
Z	4	4
Radiation type	Mo Kα	Mo Kα
µ (mm⁻¹)	0.60	0.51
Crystal size (mm)	0.15 × 0.04 × 0.02	0.32 × 0.24 × 0.06

Data collection
Diffractometer	Nonius KappaCCD area-detector	Nonius KappaCCD area-detector
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003)	Multi-scan (SADABS; Sheldrick, 2003)
T_min, T_max	0.919, 0.988	0.853, 0.970
No. of measured, independent and observed [I > 2σ(I)] reflections	6842, 936, 736	6231, 1386, 1093
R_int	0.096	0.044
(sin θ/λ)_max (Å⁻¹)	0.653	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.038, 0.102, 1.08	0.045, 0.113, 1.10
No. of reflections	936	1386
No. of parameters	59	91
H-atom treatment	H-atom parameters constrained	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.39, −0.38	0.33, −0.35

Computer programs: COLLECT (Nonius, 1999), DENZO (Otwinowski & Minor, 1997) and COLLECT, DENZO and COLLECT, WinGX (Farrugia, 1999) and SIR92 (Altomare et al., 1993), OSCAIL (McArdle, 2003) and SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), SHELXL97 and PRPKAPPA (Ferguson, 1999).

Hydrogen-bond geometry (Å, º) for (I) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···N3ⁱ	0.87	2.13	2.999 (3)	175
N2—H22···N4ⁱⁱ	0.89	2.08	2.969 (2)	172

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, y, z−1.

Hydrogen-bond geometry (Å, º) for (II) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···N3ⁱ	0.84	2.16	2.985 (3)	171
N2—H22···N4ⁱⁱ	0.87	2.10	2.959 (3)	169

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+1/2, z+1/2.

Selected geometric parameters (Å, °) for compounds (I) and (II) top

Parameter	(I)	(II)
S1—C2	1.745 (2)	1.749 (2)
C2—N3	1.323 (2)	1.328 (3)
N3—N4	1.390 (2)	1.378 (3)
N4—C5	1.293 (3)	1.291 (3)
C5—S1	1.735 (2)	1.727 (2)
C2—N2	1.345 (3)	1.325 (3)
C5—C51		1.494 (4)

C5—S1—C2	86.59 (10)	86.31 (11)
S1—C2—N3	113.86 (15)	113.56 (18)
C2—N3—N4	111.73 (16)	111.81 (19)
N3—N4—C5	113.04 (16)	113.03 (19)
N4—C5—S1	114.78 (16)	115.29 (19)
S1—C2—N2	121.89 (14)	122.35 (17)
N3—C2—N2	124.25 (19)	124.1 (2)

Acknowledgements

The X-ray data were collected at the EPSRC X-ray Crystallographic Service, University of Southampton, England; the authors thank the staff for all their help and advice. SMSVW thanks CNPq and FAPERJ for financial support.

References

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ISSN: 2053-2296

Volume 62| Part 1| January 2006| Pages o42-o44

doi:10.1107/S0108270105040126

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