2-Methoxy­benz­aldehyde thio­semicarbazone

The title mol­ecule, C₉H₁₁N₃OS, exhibits a trans conformation with respect to the phenyl ring and the thio­semicarbazone moiety. The dihedral angle between the thio­semicarbazone moiety and the phenyl ring is 4.68 (5)°. In the solid state, inversion-related mol­ecules exist as centrosymmetric N—H...S hydrogen-bonded dimers. Symmetry-related dimers are interlinked by N—H...S and N—H...O intermolecular hydrogen bonds, forming two-dimensional molecular networks parallel to the ab plane.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.044
• wR factor = 0.126
• Data-to-parameter ratio = 19.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

Thiosemicarbazones are derivatives of carbonyl compounds which exhibit a wide range of biological activities (Shanmuga Sundara Raj et al., 2000). There is a considerable interest in the chemistry of Schiff base compounds containing N– and S-donors and their metal complexes. This is due to their non-linear optical properties and chelating ability with transition metal ions (Ali & Tarafdar, 1977; Ali & Bose, 1984; Tian et al., 1996). Antibacterial, antiviral and antitumour activities have been observed in N– and S-donor ligands, such as substituted thiosemicarbazides and thiosemicarbazones (Nandi et al., 1984; French & Blanz, 1965, 1966; William, 1972). In this paper, we report the structure of 2-methoxybenzaldehyde thiosemicarbazone, (I).

The molecular structure of (I), with the atom-numbering scheme, is shown in Fig. 1. The bond distances agree well with the values reported for similar structures (Moers et al., 1999; Nandi et al., 1984; Shanmuga Sundara Raj et al., 2000). The C—S bond [1.688 (2) Å] has a length intermediate between a single and double bond. The sum of the valence angles around atoms N1 and N2 indicate that these atoms are sp² hybridized. The exocyclic angles around atom C4 atom show considerable asymmetry, with the O1—C4—C5 angle [123.9 (2)°] being wider than O1—C4—C3 [115.9 (1)°], as observed in a related structure (Fun et al., 1996). This may be due to the steric repulsion between the methyl group and the phenyl ring. The C9—O1—C4—C5 [−14.1 (3)°] and C9—O1—C4—C3 [166.4 (2)°] torsion angles indicate that the methoxy group is twisted away from the benzene plane. The S1—C1—N2—N3 [−177.6 (1)°] and N3—C2—C3—C4 [−178.1 (2)°] torsion angles show a trans conformation between the thiosemicarbazone moiety and the phenyl ring. The trans conformation adopted by the side chain is evident from the values of the C1—N2—N3—C2 [172.8 (2)°], N2—N3—C2—C3 [−178.6 (1)°], N3—C2—C3—C4 [−178.1 (2)°] and C2—C3—C4—C5 [−178.4 (2)°] torsion angles. The thiosemicarbazone moiety forms a dihedral angle of 4.68 (5)° with the phenyl ring.

In the crystal, the molecules at (x, y, z) and (-x, 1 − y, 1 − z) are linked by N—H···S hydrogen bonds involving the NH group, forming centrosymmetric dimeric units. Symmetry-related dimers are interlinked by N—H···S and N—H···O intermolecular hydrogen bonds involving the NH₂ group (Table 2), forming two-dimensional molecular networks parallel to the ab plane (Fig. 2). The N···S distances of 3.376 (1) and 3.398 (1) Å are close to the mean N···S distance reported for N—H···S hydrogen bonds by Srinivasan & Chacko (1967).

S2. Experimental

2-Methoxybenzaldehyde and thiosemicarbazide, taken almost in equivalent quantities, with a few drops of HCl, formed 2-methoxybenzaldehyde thiosemicarbazone. Single crystals suitable for X-ray diffraction analysis were obtained by slow evaporation from an acetone solution at room temperature.

S3. Refinement

All H atoms were positioned geometrically and were treated as riding on their parent C and N atoms, with C—H distances of 0.93 or 0.96 Å and N—H distances of 0.86 Å.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek,1990); software used to prepare material for publication: SHELXL97 and PARST (Nardelli, 1995).

Figures

	Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are shown at the 50% probability level.
	Fig. 2. The packing of the title molecules, viewed down the b axis.

2-methoxybenzaldehyde thiosemicarbazone

Crystal data

C9H11N3OS	F(000) = 880
Mr = 209.27	Dx = 1.347 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 6556 reflections
a = 13.5826 (2) Å	θ = 2.8–28.3°
b = 10.6063 (2) Å	µ = 0.28 mm^−1
c = 14.3260 (3) Å	T = 293 K
V = 2063.82 (7) Å^3	Block, colourless
Z = 8	0.48 × 0.34 × 0.20 mm

Data collection

Siemens SMART CCD area-detector diffractometer	1742 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.079
Graphite monochromator	θmax = 28.3°, θmin = 2.8°
ω scans	h = −18→17
13626 measured reflections	k = −14→10
2547 independent reflections	l = −19→13

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.044	H-atom parameters constrained
wR(F^2) = 0.126	w = 1/[σ^2(Fo^2) + (0.0674P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.98	(Δ/σ)max < 0.001
2547 reflections	Δρmax = 0.32 e Å^−3
128 parameters	Δρmin = −0.34 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0093 (15)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S1	0.14359 (3)	0.45821 (4)	0.44357 (4)	0.0513 (2)
O1	−0.13883 (8)	0.92320 (12)	0.70048 (9)	0.0457 (4)
N1	0.22790 (10)	0.68344 (12)	0.44969 (11)	0.0408 (4)
H1A	0.2306	0.7605	0.4682	0.049*
H1B	0.2734	0.6537	0.4142	0.049*
N2	0.08486 (10)	0.66244 (12)	0.53117 (10)	0.0369 (4)
H2	0.0371	0.6171	0.5518	0.044*
N3	0.09090 (10)	0.78810 (12)	0.55478 (10)	0.0340 (3)
C1	0.15382 (10)	0.61077 (15)	0.47576 (12)	0.0326 (4)
C2	0.01710 (12)	0.83237 (15)	0.59910 (12)	0.0331 (4)
H2A	−0.0350	0.7792	0.6142	0.040*
C3	0.01285 (12)	0.96481 (14)	0.62651 (11)	0.0326 (4)
C4	−0.06784 (12)	1.01062 (15)	0.67780 (12)	0.0363 (4)
C5	−0.07296 (16)	1.13717 (18)	0.70187 (14)	0.0499 (5)
H5	−0.1262	1.1671	0.7362	0.060*
C6	0.00098 (18)	1.21846 (17)	0.67485 (15)	0.0552 (6)
H6	−0.0031	1.3034	0.6905	0.066*
C7	0.08079 (16)	1.17500 (18)	0.62491 (15)	0.0515 (5)
H7	0.1306	1.2304	0.6075	0.062*
C8	0.08671 (14)	1.04948 (16)	0.60076 (13)	0.0397 (4)
H8	0.1406	1.0208	0.5669	0.048*
C9	−0.21108 (16)	0.9580 (2)	0.76991 (16)	0.0615 (6)
H9A	−0.2559	0.8892	0.7793	0.092*
H9B	−0.2469	1.0307	0.7489	0.092*
H9C	−0.1785	0.9771	0.8276	0.092*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0425 (3)	0.0245 (3)	0.0868 (5)	−0.00013 (17)	0.0173 (2)	−0.0103 (2)
O1	0.0379 (7)	0.0513 (8)	0.0480 (8)	0.0038 (5)	0.0040 (6)	−0.0136 (6)
N1	0.0343 (7)	0.0288 (7)	0.0594 (11)	−0.0021 (6)	0.0112 (7)	−0.0081 (6)
N2	0.0365 (7)	0.0242 (7)	0.0499 (10)	−0.0006 (5)	0.0101 (6)	−0.0031 (6)
N3	0.0369 (7)	0.0258 (7)	0.0395 (9)	0.0025 (6)	0.0009 (6)	−0.0036 (6)
C1	0.0300 (8)	0.0263 (8)	0.0416 (10)	0.0038 (6)	−0.0006 (7)	0.0001 (7)
C2	0.0351 (8)	0.0320 (9)	0.0322 (9)	0.0023 (6)	−0.0017 (7)	−0.0018 (7)
C3	0.0387 (9)	0.0301 (8)	0.0291 (9)	0.0046 (6)	−0.0077 (7)	−0.0035 (6)
C4	0.0420 (9)	0.0371 (9)	0.0298 (9)	0.0079 (7)	−0.0087 (7)	−0.0081 (7)
C5	0.0646 (13)	0.0437 (11)	0.0415 (12)	0.0149 (9)	−0.0080 (9)	−0.0146 (8)
C6	0.0865 (16)	0.0318 (10)	0.0472 (12)	0.0051 (10)	−0.0144 (11)	−0.0116 (9)
C7	0.0721 (14)	0.0350 (11)	0.0474 (13)	−0.0104 (9)	−0.0104 (10)	−0.0043 (9)
C8	0.0475 (10)	0.0359 (10)	0.0358 (11)	−0.0002 (7)	−0.0049 (8)	−0.0023 (7)
C9	0.0540 (13)	0.0833 (16)	0.0472 (14)	0.0114 (11)	0.0128 (10)	−0.0114 (11)

Geometric parameters (Å, º)

S1—C1	1.688 (2)	C3—C4	1.406 (2)
O1—C4	1.377 (2)	C4—C5	1.387 (2)
O1—C9	1.445 (2)	C5—C6	1.379 (3)
N1—C1	1.321 (2)	C5—H5	0.93
N1—H1A	0.86	C6—C7	1.378 (3)
N1—H1B	0.86	C6—H6	0.93
N2—C1	1.345 (2)	C7—C8	1.378 (2)
N2—N3	1.377 (2)	C7—H7	0.93
N2—H2	0.86	C8—H8	0.93
N3—C2	1.276 (2)	C9—H9A	0.96
C2—C3	1.460 (2)	C9—H9B	0.96
C2—H2A	0.93	C9—H9C	0.96
C3—C8	1.396 (2)
C4—O1—C9	117.79 (14)	C5—C4—C3	120.21 (17)
C1—N1—H1A	120.0	C6—C5—C4	119.91 (19)
C1—N1—H1B	120.0	C6—C5—H5	120.0
H1A—N1—H1B	120.0	C4—C5—H5	120.0
C1—N2—N3	119.86 (13)	C5—C6—C7	120.62 (17)
C1—N2—H2	120.1	C5—C6—H6	119.7
N3—N2—H2	120.1	C7—C6—H6	119.7
C2—N3—N2	115.56 (14)	C8—C7—C6	119.96 (19)
N1—C1—N2	117.36 (14)	C8—C7—H7	120.0
N1—C1—S1	122.99 (12)	C6—C7—H7	120.0
N2—C1—S1	119.64 (12)	C7—C8—C3	120.88 (18)
N3—C2—C3	121.26 (15)	C7—C8—H8	119.6
N3—C2—H2A	119.4	C3—C8—H8	119.6
C3—C2—H2A	119.4	O1—C9—H9A	109.5
C8—C3—C4	118.42 (15)	O1—C9—H9B	109.5
C8—C3—C2	121.30 (15)	H9A—C9—H9B	109.5
C4—C3—C2	120.26 (15)	O1—C9—H9C	109.5
O1—C4—C5	123.9 (2)	H9A—C9—H9C	109.5
O1—C4—C3	115.9 (1)	H9B—C9—H9C	109.5
C1—N2—N3—C2	172.8 (2)	C8—C3—C4—C5	−0.1 (2)
N3—N2—C1—N1	3.1 (2)	C2—C3—C4—C5	−178.4 (2)
N3—N2—C1—S1	−177.6 (1)	O1—C4—C5—C6	−179.0 (2)
N2—N3—C2—C3	−178.6 (1)	C3—C4—C5—C6	0.5 (3)
N3—C2—C3—C8	3.6 (2)	C4—C5—C6—C7	−0.7 (3)
N3—C2—C3—C4	−178.1 (2)	C5—C6—C7—C8	0.6 (3)
C9—O1—C4—C5	−14.1 (3)	C6—C7—C8—C3	−0.2 (3)
C9—O1—C4—C3	166.4 (2)	C4—C3—C8—C7	0.0 (3)
C8—C3—C4—O1	179.4 (2)	C2—C3—C8—C7	178.31 (16)
C2—C3—C4—O1	1.0 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···O1	0.93	2.42	2.7427 (19)	100
N1—H1A···N3	0.86	2.29	2.6385 (19)	105
N1—H1B···O1^i	0.86	2.19	3.0306 (18)	166
N1—H1A···S1^ii	0.86	2.73	3.3982 (14)	136
N2—H2···S1^iii	0.86	2.58	3.3759 (14)	154

Symmetry codes: (i) x+1/2, −y+3/2, −z+1; (ii) −x+1/2, y+1/2, z; (iii) −x, −y+1, −z+1.