2-Hydroxy­acetophenone 4-phenyl­thio­semicarbazone

The title compound, C₁₅H₁₅N₃OS, exists in the thione form and adopts an E configuration about the hydrazine bond, which is in the Z form with respect to the thiocarbonyl bond. An O—H...N intra­molecular hydrogen bond promotes planarity in part of the mol­ecule.

S1. Comment

Thiosemicarbazones of 2-hydroxyacetophenone and its derivatives are a class of versatile tridentate ONS-donor ligands capable of stabilizing both higher and lower oxidation states of transition metal ions. The biological activities of these ligands are related to their chelating ability with transition metal ions through phenol O, azomethine N and thiolate S atoms (John et al., 2004, and references therein). The coordination chemistry of these compounds has been of considerable interest as they can act as dianionic chelating ligands (John et al., 2002). The presence of bulky groups at the terminal 4-position increases the biological activity (Durham et al., 1974). de Sousa et al. (2001) have reported the title compound, (I), and its tin(IV) complexes but without a crystal structure study of (I).

Compound (I) (Fig. 1 and Table 1) adopts an alternative configuration to the recently reported 2-hydroxyacetophenone N(4)-cyclohexyl thiosemicarbazone (Seena et al., 2005; hereafter hapct). Atom S1 is in the Z form with azomethine atom N1 with respect to the N2—C8 bond [S1—C8—N2—N1 = 10.5 (2)°], unlike the E configuration seen in hapct. Furthermore, the E conformation of atom S1 and atom C9 of the phenyl ring in (I) about the C8—N3 bond [S1—C8—N3—C9 = −179.80 (14)°] is different from the Z conformation seen for those atoms in hapct. The N—H···S dimer ring involving intermolecular hydrogen bonds in compound (I) (Table 2), which utilizes atom N3 rather than the N2 atom used in hapct, may promote this conformation change.

The C8═S1 and C8—N2 and C8—N3 bond distances (Table 1) are close to C═S double bonds and C—N single bonds in thiosemicarbazones (Usman et al., 2002; Chattopadhyay et al., 1988; Latheef et al., 2006) and confirm the thione form for (I). The C8═S1 bond length of (I) is in agreement with its di-2-pyridyl (Suni et al., 2006), 2-acetylpyridine (Bermejo et al., 1999) and acetophenone (Jian et al., 2005) counterparts, but is less than the 1.688 (2) Å value in hapct. The decrease of 0.017 (3) Å for the C8—N3 bond distance compared with C8—N2 suggests greater double-bond character to the former and increased electron localization at this substituted end. This is confirmed by the typical double-bond length for N1═C7 and the considerable decrease [0.048 (2) Å] from the single-bond length for N3—C9 (Huheey et al., 1993). On complexation, the coordination occurs through the thiolate form, and the C—S bond length increases to 1.734 (3) and 1.754 (8) Å in the Sn^IV complexes [SnMe₂(L)] and [SnBu₂(L)], respectively (de Sousa et al., 2001), where L is the doubly deprotonated form of (I). The enolization on coordination leads to changes in the N2—C8, N1—N2 and N3—C8 bond lengths, although the overall conformation of (I) is retained.

The 2-hydroxyacetophenone thiosemicarbazone group excluding atoms S1 and N3 is approximately planar, with a maximum deviation of 0.074 (2) Å for atom C3. This planarity is associated with the six-membered ring (O1/H1O1/N1/C7/C6/C1) formed via the intramolecular O1—H1O1···N1 hydrogen bond (Table 2) as in salicylaldehyde 3-hexamethyleneiminyl thiosemicarbazone (Latheef et al., 2006). As a result, the exocyclic angles around atom C1 and angles subtended at C7 show considerable asymmetry (Table 1). The core thiosemicarbazone group (C7/N1/N2/C8/S1/N3/C9) is also approximately planar, with a maximum deviation from the mean plane of 0.0813 (14) Å for atom N1; this plane makes a dihedral angle of 15.88 (6)° with the plane comprising atoms O1 and C1–C6. The phenyl substituent is twisted away from this thiosemicarbazone plane with an interplanar angle of 48.46 (7)°.

Two kinds of intermolecular hydrogen bonds (Fig. 2) are seen in the packing. The molecules are paired using N3—H1N3···S1 interactions, and a three-dimensional motif is formed using a second weak intermolecular hydrogen bond, C11—H11···O1, and the C10—H10···π interaction (Table 2; Cg1 is the centre of the C1–C6 ring).

S2. Experimental

2-Hydroxyacetophenone N(4)-phenylthiosemicarbazone was prepared according to the reported method (de Sousa et al., 2001). To a hot methanol (volume?) solution of 4-phenylthiosemicarbazide (0.83615 g m, 5 mmol), a methanol (volume?) solution of 2-hydroxyacetophenone (0.6 ml, 5 mmol) was added with constant stirring. The mixture was refluxed for 4 h. After cooling, the resulting pale-yellow compound was filtered off, washed with methanol and ether, and finally dried over P₄O₁₀ in vacuo. Yellow block crystals suitable for X-ray analysis were obtained by slow evaporation from a solution in a mixture of methanol–ethyl ether (1:1) after one week. Elemental analysis found: C 62.61, H 5.35, N 14.57%; calculated: C 63.13, H 5.30, N 14.73%.

S3. Refinement

Atoms H1O1, H1N2 and H1N3 were located from difference maps and refined with isotropic displacement parameters. All other H atoms were positioned geometrically and treated as riding on their parent C atoms, with C—H distances of 0.93 and 0.96 Å, and with U_iso(H) values of 1.2U_eq(C) for aromatic and 1.5 U_eq(C) for methyl H atoms.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; 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, 2003); software used to prepare material for publication: SHELXL97 and PLATON.

Figures

	Fig. 1. Compound (I), with 50% probability displacement ellipsoids and the atom-numbering scheme. H atoms are shown as small spheres of arbitrary radii
	Fig. 2. A view of the unit cell of (I) along the b axis. The intermolecular and main intramolecular hydrogen bonds (Table 2) are shown as dashed lines. The atom labels * and # correspond to symmetry codes i and ii in Table 2.

2-Hydroxyacetophenone 4-phenylthiosemicarbazone

Crystal data

C15H15N3OS	F(000) = 1200
Mr = 285.36	Dx = 1.299 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 7838 reflections
a = 16.858 (2) Å	θ = 3.1–30.0°
b = 7.449 (2) Å	µ = 0.22 mm^−1
c = 23.312 (7) Å	T = 293 K
β = 94.390 (15)°	Block, yellow
V = 2918.7 (12) Å^3	0.30 × 0.25 × 0.20 mm
Z = 8

Data collection

Oxford Diffraction Xcalibur-S diffractometer	2552 independent reflections
Radiation source: Enhanced (Mo) X-ray Source	1947 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
Detector resolution: 15.9948 pixels mm^-1	θmax = 25.0°, θmin = 3.1°
ω scans	h = −20→20
Absorption correction: multi-scan Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm in CrysAlis RED (Oxford Diffraction, 2006)	k = −8→8
Tmin = 0.867, Tmax = 0.959	l = −27→26
12882 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.095	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0534P)^2 + 0.928P] where P = (Fo^2 + 2Fc^2)/3
2552 reflections	(Δ/σ)max < 0.001
194 parameters	Δρmax = 0.14 e Å^−3
0 restraints	Δρmin = −0.28 e Å^−3

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	0.06579 (3)	0.62773 (8)	0.335836 (18)	0.0710 (2)
N1	0.00345 (8)	0.71367 (19)	0.44695 (5)	0.0506 (3)
N2	−0.05294 (9)	0.66726 (19)	0.40384 (5)	0.0517 (4)
N3	−0.08904 (8)	0.6221 (2)	0.30838 (6)	0.0556 (4)
O1	0.14659 (10)	0.8045 (2)	0.47266 (6)	0.0854 (5)
C1	0.12289 (12)	0.8300 (2)	0.52616 (7)	0.0629 (5)
C2	0.18009 (14)	0.8945 (3)	0.56731 (9)	0.0794 (6)
H2	0.2314	0.9173	0.5571	0.095*
C3	0.16157 (18)	0.9246 (3)	0.62259 (9)	0.0872 (7)
H3	0.2003	0.9670	0.6498	0.105*
C4	0.08616 (18)	0.8926 (3)	0.63797 (9)	0.0923 (8)
H4	0.0736	0.9142	0.6755	0.111*
C5	0.02904 (14)	0.8286 (3)	0.59808 (7)	0.0748 (6)
H5	−0.0219	0.8067	0.6092	0.090*
C6	0.04526 (11)	0.7952 (2)	0.54096 (6)	0.0537 (4)
C7	−0.01801 (10)	0.7331 (2)	0.49855 (6)	0.0500 (4)
C8	−0.02948 (10)	0.6404 (2)	0.34983 (6)	0.0503 (4)
C9	−0.17258 (9)	0.6297 (2)	0.31309 (6)	0.0464 (4)
C10	−0.20886 (10)	0.5342 (2)	0.35468 (7)	0.0538 (4)
H10	−0.1785	0.4650	0.3813	0.065*
C11	−0.29042 (11)	0.5421 (3)	0.35637 (8)	0.0672 (5)
H11	−0.3148	0.4798	0.3848	0.081*
C12	−0.33573 (11)	0.6409 (3)	0.31664 (8)	0.0692 (5)
H12	−0.3907	0.6455	0.3180	0.083*
C13	−0.29976 (11)	0.7329 (3)	0.27475 (8)	0.0632 (5)
H13	−0.3305	0.7992	0.2475	0.076*
C14	−0.21861 (10)	0.7279 (2)	0.27275 (6)	0.0542 (4)
H14	−0.1946	0.7906	0.2442	0.065*
C15	−0.10042 (11)	0.6981 (3)	0.51574 (7)	0.0672 (5)
H15A	−0.1285	0.8098	0.5177	0.101*
H15B	−0.0975	0.6408	0.5527	0.101*
H15C	−0.1280	0.6214	0.4878	0.101*
H1N2	−0.1021 (11)	0.696 (3)	0.4067 (8)	0.068 (6)*
H1N3	−0.0745 (11)	0.622 (3)	0.2752 (8)	0.069 (6)*
H1O1	0.1082 (14)	0.770 (3)	0.4518 (11)	0.099 (9)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0587 (3)	0.1139 (5)	0.0424 (2)	−0.0003 (3)	0.01542 (19)	−0.0021 (2)
N1	0.0658 (8)	0.0516 (8)	0.0353 (6)	0.0042 (6)	0.0084 (6)	0.0036 (6)
N2	0.0560 (8)	0.0649 (10)	0.0353 (7)	0.0063 (7)	0.0112 (6)	0.0013 (6)
N3	0.0573 (8)	0.0786 (10)	0.0326 (7)	−0.0005 (7)	0.0139 (6)	0.0007 (7)
O1	0.0818 (10)	0.1256 (14)	0.0497 (7)	−0.0303 (9)	0.0104 (7)	0.0099 (8)
C1	0.0919 (14)	0.0524 (11)	0.0437 (9)	−0.0053 (9)	−0.0001 (9)	0.0111 (7)
C2	0.1000 (15)	0.0638 (13)	0.0714 (13)	−0.0127 (11)	−0.0124 (11)	0.0129 (10)
C3	0.135 (2)	0.0579 (13)	0.0634 (13)	0.0111 (13)	−0.0287 (13)	−0.0078 (10)
C4	0.139 (2)	0.0872 (17)	0.0491 (11)	0.0371 (16)	−0.0068 (13)	−0.0164 (11)
C5	0.1036 (16)	0.0771 (14)	0.0438 (10)	0.0283 (11)	0.0057 (9)	−0.0071 (9)
C6	0.0811 (12)	0.0427 (9)	0.0377 (8)	0.0115 (8)	0.0062 (7)	0.0050 (7)
C7	0.0720 (11)	0.0412 (9)	0.0380 (8)	0.0123 (8)	0.0126 (7)	0.0072 (7)
C8	0.0619 (10)	0.0536 (10)	0.0367 (8)	0.0023 (8)	0.0124 (7)	0.0043 (7)
C9	0.0592 (9)	0.0455 (9)	0.0359 (7)	−0.0016 (7)	0.0127 (6)	−0.0031 (6)
C10	0.0703 (11)	0.0505 (10)	0.0421 (8)	−0.0020 (8)	0.0140 (7)	0.0061 (7)
C11	0.0760 (12)	0.0766 (13)	0.0523 (10)	−0.0146 (10)	0.0265 (9)	0.0007 (9)
C12	0.0593 (10)	0.0877 (15)	0.0629 (11)	0.0029 (10)	0.0193 (9)	−0.0085 (10)
C13	0.0688 (11)	0.0625 (12)	0.0583 (10)	0.0106 (9)	0.0039 (8)	0.0001 (9)
C14	0.0710 (11)	0.0519 (10)	0.0405 (8)	−0.0046 (8)	0.0106 (7)	0.0061 (7)
C15	0.0786 (12)	0.0784 (13)	0.0472 (9)	0.0125 (10)	0.0214 (8)	0.0078 (9)

Geometric parameters (Å, º)

S1—C8	1.6659 (16)	C5—C6	1.402 (2)
N1—C7	1.2905 (19)	C5—H5	0.9300
N1—N2	1.3736 (19)	C6—C7	1.472 (2)
N2—C8	1.3631 (19)	C7—C15	1.498 (2)
N2—H1N2	0.864 (19)	C9—C14	1.382 (2)
N3—C8	1.346 (2)	C9—C10	1.383 (2)
N3—C9	1.422 (2)	C10—C11	1.380 (2)
N3—H1N3	0.829 (19)	C10—H10	0.9300
O1—C1	1.352 (2)	C11—C12	1.369 (3)
O1—H1O1	0.82 (2)	C11—H11	0.9300
C1—C2	1.393 (3)	C12—C13	1.372 (3)
C1—C6	1.403 (3)	C12—H12	0.9300
C2—C3	1.368 (3)	C13—C14	1.373 (2)
C2—H2	0.9300	C13—H13	0.9300
C3—C4	1.368 (3)	C14—H14	0.9300
C3—H3	0.9300	C15—H15A	0.9600
C4—C5	1.372 (3)	C15—H15B	0.9600
C4—H4	0.9300	C15—H15C	0.9600
C7—N1—N2	118.85 (14)	C6—C7—C15	120.94 (14)
C8—N2—N1	118.64 (14)	N3—C8—N2	115.14 (14)
C8—N2—H1N2	117.2 (12)	N3—C8—S1	122.07 (11)
N1—N2—H1N2	119.6 (12)	N2—C8—S1	122.78 (12)
C8—N3—C9	128.99 (13)	C14—C9—C10	119.61 (15)
C8—N3—H1N3	114.4 (13)	C14—C9—N3	118.46 (13)
C9—N3—H1N3	115.9 (13)	C10—C9—N3	121.83 (15)
C1—O1—H1O1	108.4 (17)	C11—C10—C9	119.56 (16)
O1—C1—C2	116.49 (19)	C11—C10—H10	120.2
O1—C1—C6	123.24 (16)	C9—C10—H10	120.2
C2—C1—C6	120.28 (18)	C12—C11—C10	120.62 (16)
C3—C2—C1	120.6 (2)	C12—C11—H11	119.7
C3—C2—H2	119.7	C10—C11—H11	119.7
C1—C2—H2	119.7	C11—C12—C13	119.74 (17)
C2—C3—C4	120.1 (2)	C11—C12—H12	120.1
C2—C3—H3	119.9	C13—C12—H12	120.1
C4—C3—H3	119.9	C12—C13—C14	120.43 (17)
C3—C4—C5	120.1 (2)	C12—C13—H13	119.8
C3—C4—H4	120.0	C14—C13—H13	119.8
C5—C4—H4	120.0	C13—C14—C9	120.03 (15)
C4—C5—C6	121.8 (2)	C13—C14—H14	120.0
C4—C5—H5	119.1	C9—C14—H14	120.0
C6—C5—H5	119.1	C7—C15—H15A	109.5
C5—C6—C1	117.02 (18)	C7—C15—H15B	109.5
C5—C6—C7	120.62 (17)	H15A—C15—H15B	109.5
C1—C6—C7	122.31 (14)	C7—C15—H15C	109.5
N1—C7—C6	114.88 (15)	H15A—C15—H15C	109.5
N1—C7—C15	124.18 (15)	H15B—C15—H15C	109.5
C7—N1—N2—C8	−177.59 (15)	C5—C6—C7—C15	−2.0 (2)
O1—C1—C2—C3	179.90 (19)	C1—C6—C7—C15	−179.70 (16)
C6—C1—C2—C3	0.1 (3)	C9—N3—C8—N2	1.1 (3)
C1—C2—C3—C4	−0.4 (3)	C9—N3—C8—S1	−179.80 (14)
C2—C3—C4—C5	0.6 (4)	N1—N2—C8—N3	−170.43 (14)
C3—C4—C5—C6	−0.4 (3)	N1—N2—C8—S1	10.5 (2)
C4—C5—C6—C1	0.1 (3)	C8—N3—C9—C14	135.13 (18)
C4—C5—C6—C7	−177.66 (18)	C8—N3—C9—C10	−48.5 (3)
O1—C1—C6—C5	−179.74 (18)	C14—C9—C10—C11	−1.8 (2)
C2—C1—C6—C5	0.1 (3)	N3—C9—C10—C11	−178.12 (15)
O1—C1—C6—C7	−2.0 (3)	C9—C10—C11—C12	1.2 (3)
C2—C1—C6—C7	177.79 (17)	C10—C11—C12—C13	0.0 (3)
N2—N1—C7—C6	−175.87 (13)	C11—C12—C13—C14	−0.6 (3)
N2—N1—C7—C15	3.6 (2)	C12—C13—C14—C9	0.0 (3)
C5—C6—C7—N1	177.46 (16)	C10—C9—C14—C13	1.2 (2)
C1—C6—C7—N1	−0.2 (2)	N3—C9—C14—C13	177.65 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H1N3···S1^i	0.829 (19)	2.604 (19)	3.4148 (18)	166.0 (17)
O1—H1O1···N1	0.82 (2)	1.81 (2)	2.534 (2)	146 (2)
C11—H11···O1^ii	0.93	2.55	3.471 (3)	168
C10—H10···Cg1^iii	0.93	2.83	3.681 (2)	152

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