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Crystal structure of (E)-2-hy­dr­oxy-1,2-di­phenyl­ethan-1-one oxime

aInstitute of Chemistry of New Materials, University of Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany, and bDepartamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carerra 30 No 45-03, Bogotá, Colombia
*Correspondence e-mail: hreuter@uos.de

Edited by M. Weil, Vienna University of Technology, Austria (Received 1 June 2017; accepted 14 June 2017; online 20 June 2017)

The title compound, C14H13NO2, is a commercially available material and can be used as a multidentate ligand. The mol­ecule of the asymmetric unit has an R configuration, while the corresponding S-configured mol­ecule of the racemic mixture is generated by a crystallographic centre of symmetry. Both hy­droxy groups (the H atom of the oxime group is equally disordered over two positions) are involved in hydrogen bonding, leading to the formation of chains extending parallel to [001].

1. Chemical context

The title compound (E)-2-hy­droxy-1,2-diphenyl-ethan-1-one oxime, C14H13NO2, is commercially available and can be used as a multidentate ligand for which many trivial names such as cuprone or alpha-benzoin, and abbreviations including AboH2, BzoxH2, are in use. Used for a long time for the determination of manganese or copper in steel (Feigl, 1923[Feigl, F. (1923). Chem. Ber. 56, 2083-2085.]; Knowles, 1932[Knowles, H. B. (1932). J. Res. Nat. Bur. Stand. 9, 1-7.]; Kar, 1935[Kar, H. A. (1935). Ind. Eng. Chem. Anal. Ed. 7, 193.]), BzoxH2 has attracted considerable attention nowadays in the coordination chemistry of transition metals for the preparation of mol­ecular wheels and high-nuclearity metal units with copper, manganese or nickel cations (Stamatatos et al., 2012[Stamatatos, T. C., Vlahopoulou, G., Raptopoulou, C. P., Psycharis, V., Escuer, A., Christou, G. & Perlepes, S. P. (2012). Eur. J. Inorg. Chem. pp. 3121-3131.]; Vlahopoulou et al., 2009[Vlahopoulou, G. C., Stamatatos, T. C., Psycharis, V., Perlepes, S. P. & Christou, G. (2009). Dalton Trans. pp. 3646-3649.]; Koumousi et al. 2010[Koumousi, E. S., Manos, M., Lampropoulos, C., Tasiopoulos, A. J., Wernsdorfer, W., Christou, G. & Stamatatos, T. C. (2010). Inorg. Chem. 49, 3077-3079.]; Karotsis et al., 2009[Karotsis, G., Stoumpos, C., Collins, A., White, F., Parsons, S., Slawin, A. M. Z., Papaefstathiou, G. S. & Brechin, E. K. (2009). Dalton Trans. pp. 3388.]). In the course of a project to evaluate the reactivity of BzoxH2 towards organotin(IV) compounds, we obtained high-quality single crystals of the title compound which we have used for structure determination by X-ray diffraction.

[Scheme 1]

2. Structural commentary

BzoxH2 crystallizes in the centrosymmetric monoclinic space group C2/c with eight mol­ecules in the unit cell and one mol­ecule in the asymmetric unit. As the compound possesses an asymmetric carbon atom (C2), the mol­ecule of the asymmetric unit has an R-configuration while the corresponding S-configured mol­ecule of the racemic mixture is generated by a crystallographic centre of symmetry. Both mol­ecules also show the E configuration at the N=C double bond of the oxime moiety (Fig. 1[link]).

[Figure 1]
Figure 1
The asymmetric unit of the title compound, showing the atom-labelling scheme and displacement ellipsoids for the non-H atoms at the 50% probability level; split positions of the H atom attached to atom O2 are labelled H3 and H4.

The length [1.278 (2) Å] of the N=C double bond (Table 1[link]) is consistent with the value of 1.281 (13) Å found in other oxime moieties (Allen et al., 1987[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.]). In addition, this moiety is characterized by a bond angle of 115.5 (1)° at the N atom and of 102.1° at the O atom. The central C—C bond of the mol­ecule has a length of 1.525 (2), which is also in good accord­ance with a typical single bond between sp3 (C2) and sp2 (C1) hybridized C atoms. As a consequence of the different hybridization states, however, the bonds of these two carbon atoms to their phenyl groups are slightly different: 1.512 (2) Å for C2 and 1.484 (2) Å for C1, respectively. The hy­droxy group attached to C2 shows a C—O bond length of 1.425 (2) Å, which also lies in the normal range (1.421–1.433 Å) of a C2–CH–OH group (Allen et al., 1987[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.]).

Table 1
Selected geometric parameters (Å, °)

O1—N1 1.404 (1) C1—C2 1.525 (2)
C1—N1 1.278 (2) O2—C2 1.425 (2)
       
N1—C1—C2 114.3 (1) C1—N1—O1 115.5 (1)
C11—C1—C2 117.7 (1) O2—C2—C1 110.1 (1)

The two phenyl groups exhibit a mean C—C bond length of 1.387 (5) Å [variation: 1.374 (3)–1.398 (2) Å], in excellent agreement with the literature value (Allen et al., 1987[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.]) of 1.387 (10) Å for Car—Car. The mean value of the endocyclic bond angles within the phenyl rings is 120.0 (5)° with minima at the ipso carbon atoms C11 [118.3 (1)°] and C21 [119.1 (1)°]. The phenyl rings form an inter­planar angle of 80.72 (5)°.

3. Supra­molecular features

The mol­ecule possesses two hy­droxy groups which, in principle, can act as donors and acceptors for hydrogen bonding while the N atom of the oxime moiety can only act as an acceptor atom in the formation of hydrogen bonds. In fact, the crystal packing (Fig. 2[link]) with its clear separation of polar and non-polar moieties, results from two different types of hydrogen bonds (Table 2[link]), giving rise to a one-dimensional tube-like arrangement of the mol­ecules propagating along [001]. In the first type of hydrogen bond, only the hy­droxy group attached to the carbon atom C2 is involved, acting both as hydrogen-donor and hydrogen-acceptor groups (Fig. 3[link]). Since the oxygen atoms of the resulting hydrogen bonds are related to each other by a centre of symmetry [O2⋯O2ii = 2.829 (2) Å, 〈O2—H3⋯O2ii = 164°; symmetry code: (ii) = −x + 1, −y, −z + 1] and a twofold rotation axis [O2⋯O2iii = 2.806 (2) Å, 〈O2—H4⋯O1iii = 175°; symmetry code (iii) = −x + 1, y, −z + [{1\over 2}]], respectively, the hydrogen atom of the hy­droxy group breaks space-group symmetry, which was considered in the structure model by two equally disordered split positions [H3/H4] of this hydrogen atom. While this kind of hydrogen-bonding system extends to an infinite number of mol­ecules, the second type of hydrogen bond is limited to two neigbouring mol­ecules. It involves the hy­droxy group of the oxime moiety that acts as an H-atom donor forming mutual hydrogen bonds with the nitro­gen atom of the oxime moiety of a neighbouring mol­ecule, giving rise to two equivalent hydrogen bonds [O1⋯N1i = 2.805 (2) Å, 〈O1—H1⋯ N1i = 144°; symmetry code: (i) = −x + 1, y, −z + [{3\over 2}]] between these two mol­ecules (Fig. 4[link]). The two mol­ecules within the resulting six-membered ring are related to each other by a twofold rotation axis.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1⋯N1i 0.96 1.97 2.805 (2) 144
O2—H3⋯O2ii 0.96 1.89 2.829 (2) 164
O2—H4⋯O2iii 0.96 1.85 2.806 (2) 175
Symmetry codes: (i) [-x+1, y, -z+{\script{3\over 2}}]; (ii) -x+1, -y, -z+1; (iii) [-x+1, y, -z+{\script{1\over 2}}].
[Figure 2]
Figure 2
Crystal packing showing the tube-like arrangement of the mol­ecules along [001].
[Figure 3]
Figure 3
Detail of the one-dimensional hydrogen-bonding system (red dashed lines) derived from the hy­droxy group attached to the C atom looking down [010]; displacement ellipsoids for the non-H atoms are drawn at the 50% probability level. Groups attached to C atoms have been omitted for clarity. Small black dots visualize the position of an inversion center [i1: [{1\over 2}], 0, 1; i2: [{1\over 2}], 0, [{1\over 2}]; i3: [{1\over 2}], 0, 0], green dots the position of twofold rotation axes [r1: [{1\over 2}], y, [{3\over 4}]; r2: [{1\over 2}], y, [{1\over 4}]]. [Symmetry codes used to generate equivalent atoms: (1) 1 − x, y, [{1\over 2}] − z; (2) x, −y, −[{1\over 2}] + z; (3) 1 − x, −y, 1 − z; (4) x, −y, [{1\over 2}] + z; (5) 1 − x, y, [{3\over 2}] − z.]
[Figure 4]
Figure 4
Hydrogen-bonding system (red dashed lines) between the oxime groups of two neighbouring mol­ecules looking down [010]; displacement ellipsoids for the non-H atoms are given at the 50% probability level. The small green dot visualizes the position of the twofold rotation axis at [{1\over 2}], y, [{3\over 4}]. [Symmetry codes used to generate equivalent atoms: (1) 1 − x, y, [{3\over 2}] − z.]

4. Synthesis and crystallization

In a typical experiment, α-benzoinoxime was refluxed with di-n-butyl­tin oxide, C8H18OSn, in ethanol for 2.5 h. Single crystals of the title compound suitable for X-ray diffraction were obtained from the ethano­lic solution layered with n-hexane.

5. Refinement details

Crystal data, data collection and structure refinement details are summarized in Table 3[link]. All H atoms were clearly identified in difference Fourier syntheses. Those of the carbon skeleton were calculated assuming idealized geometries and allowed to ride on the carbon atoms with 1.00 Å for sp3-hybridized and 0.95 Å for aromatic H atoms, and with Uiso(H) = 1.2Ueq(C). The H atoms of the two hy­droxy groups were modelled with a common O—H distance of 0.96 Å before they were fixed and allowed to ride on the corresponding oxygen atom with Uiso(H) = 1.2Ueq(O). Disorder of the hy­droxy group attached to C2 was taken into account reducing the site occupancy of both H atoms to one-half. This suggestion was confirmed by difference-Fourier maps that clearly showed both positions.

Table 3
Experimental details

Crystal data
Chemical formula C14H13NO2
Mr 227.25
Crystal system, space group Monoclinic, C2/c
Temperature (K) 100
a, b, c (Å) 24.1434 (9), 10.5348 (4), 8.9006 (4)
β (°) 93.042 (2)
V3) 2260.64 (16)
Z 8
Radiation type Mo Kα
μ (mm−1) 0.09
Crystal size (mm) 0.37 × 0.32 × 0.11
 
Data collection
Diffractometer Bruker APEXII CCD
Absorption correction Multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SADABS, SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.968, 0.990
No. of measured, independent and observed [I > 2σ(I)] reflections 50071, 2005, 1765
Rint 0.043
(sin θ/λ)max−1) 0.595
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.088, 1.08
No. of reflections 2005
No. of parameters 157
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.22, −0.18
Computer programs: APEX2 (Bruker, 2009[Bruker (2009). APEX2, SADABS, SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SAINT (Bruker, 2009[Bruker (2009). APEX2, SADABS, SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), DIAMOND (Brandenburg, 2006[Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]).

Supporting information


Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2006) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

(E)-2-Hydroxy-1,2-diphenylethan-1-one oxime top
Crystal data top
C14H13NO2F(000) = 960
Mr = 227.25Dx = 1.335 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
a = 24.1434 (9) ÅCell parameters from 1932 reflections
b = 10.5348 (4) Åθ = 3.1–24.4°
c = 8.9006 (4) ŵ = 0.09 mm1
β = 93.042 (2)°T = 100 K
V = 2260.64 (16) Å3Block, colourless
Z = 80.37 × 0.32 × 0.11 mm
Data collection top
Bruker APEXII CCD
diffractometer
1765 reflections with I > 2σ(I)
φ and ω scansRint = 0.043
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
θmax = 25.0°, θmin = 2.1°
Tmin = 0.968, Tmax = 0.990h = 2828
50071 measured reflectionsk = 1212
2005 independent reflectionsl = 1010
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.088 w = 1/[σ2(Fo2) + (0.0361P)2 + 2.1083P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max < 0.001
2005 reflectionsΔρmax = 0.22 e Å3
157 parametersΔρmin = 0.18 e Å3
Special details top

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O10.43413 (4)0.17890 (9)0.80605 (10)0.0241 (2)
H10.46930.17760.86190.029 (3)*
C10.41037 (6)0.14256 (12)0.55975 (15)0.0203 (3)
N10.44993 (5)0.16404 (11)0.65751 (12)0.0214 (3)
O20.48687 (4)0.10235 (9)0.40164 (11)0.0252 (3)
H30.49380.02310.45240.029 (3)*0.5
H40.49590.09730.29810.029 (3)*0.5
C20.42878 (6)0.12695 (13)0.39955 (15)0.0217 (3)
H20.40860.05310.35190.029 (3)*
C110.35015 (6)0.13354 (13)0.58375 (15)0.0210 (3)
C120.31705 (6)0.04617 (14)0.50248 (16)0.0253 (3)
H120.33320.00720.43070.0306 (19)*
C130.26100 (6)0.03627 (15)0.52511 (17)0.0302 (4)
H130.23910.02450.47000.0306 (19)*
C140.23671 (6)0.11432 (16)0.62737 (17)0.0311 (4)
H140.19820.10710.64320.0306 (19)*
C150.26863 (6)0.20283 (15)0.70637 (17)0.0283 (3)
H150.25180.25760.77550.0306 (19)*
C160.32497 (6)0.21281 (14)0.68598 (16)0.0247 (3)
H160.34660.27380.74170.0306 (19)*
C210.41529 (5)0.24451 (14)0.30732 (15)0.0223 (3)
C220.43786 (6)0.36078 (15)0.34820 (17)0.0292 (3)
H220.46270.36710.43440.040 (2)*
C230.42453 (7)0.46786 (16)0.2644 (2)0.0373 (4)
H230.43970.54780.29400.040 (2)*
C240.38915 (7)0.45886 (17)0.13770 (19)0.0402 (4)
H240.37970.53270.08070.040 (2)*
C250.36771 (7)0.34293 (18)0.09425 (18)0.0404 (4)
H250.34400.33620.00590.040 (2)*
C260.38058 (6)0.23623 (16)0.17912 (17)0.0312 (4)
H260.36540.15640.14910.040 (2)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0247 (5)0.0303 (6)0.0176 (5)0.0021 (4)0.0046 (4)0.0010 (4)
C10.0231 (7)0.0159 (7)0.0221 (7)0.0033 (5)0.0038 (5)0.0023 (5)
N10.0240 (6)0.0217 (6)0.0189 (6)0.0021 (5)0.0057 (5)0.0002 (5)
O20.0211 (5)0.0259 (5)0.0292 (5)0.0051 (4)0.0078 (4)0.0033 (4)
C20.0185 (7)0.0234 (7)0.0236 (7)0.0017 (5)0.0041 (5)0.0008 (6)
C110.0230 (7)0.0209 (7)0.0194 (7)0.0025 (5)0.0037 (5)0.0051 (5)
C120.0273 (8)0.0258 (8)0.0230 (7)0.0027 (6)0.0029 (6)0.0014 (6)
C130.0256 (8)0.0347 (9)0.0301 (8)0.0045 (6)0.0001 (6)0.0031 (7)
C140.0224 (8)0.0421 (9)0.0292 (8)0.0007 (7)0.0052 (6)0.0090 (7)
C150.0266 (8)0.0332 (8)0.0259 (8)0.0060 (6)0.0084 (6)0.0035 (6)
C160.0268 (8)0.0245 (7)0.0232 (7)0.0024 (6)0.0043 (6)0.0022 (6)
C210.0209 (7)0.0265 (8)0.0203 (7)0.0057 (6)0.0081 (5)0.0002 (6)
C220.0269 (8)0.0314 (8)0.0297 (8)0.0012 (6)0.0051 (6)0.0027 (7)
C230.0397 (9)0.0274 (9)0.0465 (10)0.0026 (7)0.0177 (8)0.0054 (7)
C240.0503 (10)0.0395 (10)0.0325 (9)0.0225 (8)0.0189 (8)0.0163 (8)
C250.0478 (10)0.0527 (11)0.0206 (8)0.0244 (9)0.0007 (7)0.0016 (7)
C260.0346 (8)0.0353 (9)0.0239 (8)0.0095 (7)0.0028 (6)0.0052 (7)
Geometric parameters (Å, º) top
O1—N11.404 (1)C14—C151.378 (2)
O1—H10.9600C14—H140.9500
C1—N11.278 (2)C15—C161.386 (2)
C1—C111.484 (2)C15—H150.9500
C1—C21.525 (2)C16—H160.9500
O2—C21.425 (2)C21—C221.381 (2)
O2—H30.9600C21—C261.382 (2)
O2—H40.9600C22—C231.381 (2)
C2—C211.512 (2)C22—H220.9500
C2—H21.0000C23—C241.382 (3)
C11—C121.396 (2)C23—H230.9500
C11—C161.398 (2)C24—C251.374 (3)
C12—C131.383 (2)C24—H240.9500
C12—H120.9500C25—C261.380 (2)
C13—C141.380 (2)C25—H250.9500
C13—H130.9500C26—H260.9500
N1—O1—H1102.1C13—C14—H14120.2
N1—C1—C11128.03 (12)C14—C15—C16120.70 (14)
N1—C1—C2114.3 (1)C14—C15—H15119.6
C11—C1—C2117.7 (1)C16—C15—H15119.6
C1—N1—O1115.5 (1)C15—C16—C11120.25 (14)
C2—O2—H3108.1C15—C16—H16119.9
C2—O2—H4105.7C11—C16—H16119.9
H3—O2—H4111.2C22—C21—C26119.12 (14)
O2—C2—C21109.84 (11)C22—C21—C2120.85 (13)
O2—C2—C1110.1 (1)C26—C21—C2120.02 (13)
C21—C2—C1110.75 (11)C23—C22—C21120.32 (15)
O2—C2—H2108.7C23—C22—H22119.8
C21—C2—H2108.7C21—C22—H22119.8
C1—C2—H2108.7C22—C23—C24120.07 (16)
C12—C11—C16118.33 (13)C22—C23—H23120.0
C12—C11—C1120.41 (12)C24—C23—H23120.0
C16—C11—C1121.26 (13)C25—C24—C23119.88 (15)
C13—C12—C11120.81 (13)C25—C24—H24120.1
C13—C12—H12119.6C23—C24—H24120.1
C11—C12—H12119.6C24—C25—C26119.95 (16)
C14—C13—C12120.31 (14)C24—C25—H25120.0
C14—C13—H13119.8C26—C25—H25120.0
C12—C13—H13119.8C25—C26—C21120.62 (16)
C15—C14—C13119.58 (14)C25—C26—H26119.7
C15—C14—H14120.2C21—C26—H26119.7
C11—C1—N1—O11.1 (2)C14—C15—C16—C110.5 (2)
C2—C1—N1—O1179.96 (10)C12—C11—C16—C150.8 (2)
N1—C1—C2—O217.34 (16)C1—C11—C16—C15179.89 (13)
C11—C1—C2—O2163.64 (11)O2—C2—C21—C2261.09 (16)
N1—C1—C2—C21104.31 (14)C1—C2—C21—C2260.68 (16)
C11—C1—C2—C2174.72 (15)O2—C2—C21—C26118.01 (14)
N1—C1—C11—C12143.31 (15)C1—C2—C21—C26120.23 (14)
C2—C1—C11—C1237.82 (18)C26—C21—C22—C231.9 (2)
N1—C1—C11—C1637.6 (2)C2—C21—C22—C23178.96 (13)
C2—C1—C11—C16141.28 (13)C21—C22—C23—C241.0 (2)
C16—C11—C12—C131.5 (2)C22—C23—C24—C250.7 (2)
C1—C11—C12—C13179.39 (13)C23—C24—C25—C261.4 (2)
C11—C12—C13—C140.9 (2)C24—C25—C26—C210.5 (2)
C12—C13—C14—C150.3 (2)C22—C21—C26—C251.2 (2)
C13—C14—C15—C161.1 (2)C2—C21—C26—C25179.69 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N1i0.961.972.805 (2)144
O2—H3···O2ii0.961.892.829 (2)164
O2—H4···O2iii0.961.852.806 (2)175
Symmetry codes: (i) x+1, y, z+3/2; (ii) x+1, y, z+1; (iii) x+1, y, z+1/2.
 

Acknowledgements

We thank the Deutsche Forschungsgemeinschaft and the Government of Lower-Saxony for funding the diffractometer and acknowledge support by Deutsche Forschungsgemeinschaft (DFG) and Open Access Publishing Fund of Osnabrück University.

References

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