organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 7| July 2009| Pages o1619-o1620

(E)-1-(4-Fluoro­phen­yl)ethan-1-one semicarbazone

aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bDepartment of Chemistry, National Institute of Technology–Karnataka, Surathkal, Mangalore 575 025, India
*Correspondence e-mail: hkfun@usm.my

(Received 11 June 2009; accepted 12 June 2009; online 20 June 2009)

In the title compound, C9H10FN3O, the semicarbazone group is nearly planar, with the maximum deviation of 0.044 (1) Å for one of the N atoms. The mean plane of semicarbazone group forms a dihedral angle of 30.94 (4)° with the benzene ring. The mol­ecules are linked into a supra­molecular chain by N—H⋯O hydrogen bonds formed along the c axis. The crystal structure is further stabilized by weak inter­molucular C—H⋯π inter­actions; the closest C⋯Cg contact is 3.6505 (11) Å.

Related literature

For hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For applications of semicarbazone derivatives, see: Chandra & Gupta (2005[Chandra, S. & Gupta, L. K. (2005). Spectrochim. Acta Part A, 62, 1089-1094.]); Jain et al. (2002[Jain, V. K., Handa, A., Pandya, R., Shrivastav, P. & Agrawal, Y. K. (2002). React. Funct. Polym. 51, 101-110.]); Pilgram (1978[Pilgram, K. H. G. (1978). US Patent No. 4 108 399.]); Warren et al. (1977[Warren, J. D., Woodward, D. L. & Hargreaves, R. T. (1977). J. Med. Chem. 20, 1520-1521.]); Yogeeswari et al. (2004[Yogeeswari, P., Sriram, D., Pandeya, S. N. & Stables, J. P. (2004). Farmaco, 59, 609-613.]). For the preparation of the compound, see: Furniss et al. (1978[Furniss, B. S., Hannaford, A. J., Rogers, V., Smith, P. W. G. & Tatchell, A. R. (1978). Vogel's Textbook of Practical Organic Chemistry, 4th ed., p. 1112. London: ELBS.]). For related structures, see: Fun et al. (2009a[Fun, H.-K., Chantrapromma, S., Sujith, K. V. & Kalluraya, B. (2009a). Acta Cryst. E65, o445.],b[Fun, H.-K., Goh, J. H., Padaki, M., Malladi, S. & Isloor, A. M. (2009b). Acta Cryst. E65, o1591-o1592.]). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986[Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105-107.]).

[Scheme 1]

Experimental

Crystal data
  • C9H10FN3O

  • Mr = 195.20

  • Monoclinic, P 21 /c

  • a = 18.8207 (3) Å

  • b = 6.6387 (1) Å

  • c = 7.3074 (1) Å

  • β = 95.887 (1)°

  • V = 908.21 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.11 mm−1

  • T = 100 K

  • 0.30 × 0.10 × 0.08 mm

Data collection
  • Bruker SMART APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.876, Tmax = 0.991

  • 17523 measured reflections

  • 3998 independent reflections

  • 2766 reflections with I > 2σ(I)

  • Rint = 0.033

Refinement
  • R[F2 > 2σ(F2)] = 0.049

  • wR(F2) = 0.151

  • S = 1.07

  • 3998 reflections

  • 167 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.51 e Å−3

  • Δρmin = −0.30 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H1N2⋯O1i 0.96 (2) 1.94 (2) 2.8998 (11) 179.2 (18)
N3—H2N3⋯O1ii 0.82 (2) 2.07 (2) 2.8901 (12) 176 (2)
C2—H2ACg1iii 0.989 (17) 2.927 (18) 3.7250 (12) 138.5 (12)
C5—H5ACg1iv 0.976 (14) 2.825 (13) 3.6505 (11) 142.8 (10)
Symmetry codes: (i) -x, -y+1, -z+1; (ii) -x, -y+1, -z+2; (iii) [x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]; (iv) [x, -y-{\script{1\over 2}}, z-{\script{3\over 2}}]. Cg1 is the centroid of C1–C6 benzene ring.

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

In organic chemistry, a semicarbazone is a derivative of an aldehyde or ketone formed by a condensation between a ketone or aldehyde and semicarbazide. Semicarbazones find a large number of applications in the field of synthetic chemistry, such as in medicinal chemistry (Warren et al., 1977), organometallics (Chandra & Gupta, 2005), polymers (Jain et al., 2002), and herbicides (Pilgram, 1978). 4-Sulphamoylphenyl semicarbazones were found to possess anti-convulsant activity (Yogeeswari et al., 2004). We hereby report the crystal structure of a semicarbazone of commercial importance, (I).

The bond lengths and angles for (I), Fig. 1, are comparable to those found in related structures (Fun et al., 2009a, b). A maximum deviation of 0.044 (1) Å for atom N2 from the mean plane formed by atoms O1, N1, N2, N3, C6, C7, C8 and C9, indicates that the semicarbazone group is nearly planar. This mean plane makes a dihedral angle of 30.94 (4)° with the C1–C6 benzene ring. The molecules are linked into one-dimensional chains by intermolecular N—H···O hydrogen bonds along the c axis (Fig. 2); these hydrogen bonding interactions generate R22(8) ring motifs (Bernstein et al., 1995). The crystal structure is stabilized by weak intermolecular C—H···π interactions (Table 1).

Related literature top

For hydrogen-bond motifs, see: Bernstein et al. (1995). For applications of semicarbazone derivatives, see: Chandra & Gupta (2005); Jain et al. (2002); Pilgram (1978); Warren et al. (1977); Yogeeswari et al. (2004). For the preparation of the compound, see: (Furniss et al., 1978). For related structures, see: Fun et al. (2009a,b). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986). Cg1 is the centroid of C1–C6 benzene ring.

Experimental top

Semicarbazide hydrochloride (0.86 g, 7.70 mmol) and freshly recrystallized sodium acetate (0.77 g, 9.40 mmol) were dissolved in water (10 ml) following a literature procedure (Furniss et al., 1978). The reaction mixture was stirred at room temperature for 10 minutes. To this, 4-fluoroacetophenone (1.00 g, 7.23 mmol) was added and the mixture was shaken well. A little alcohol was added to dissolve the turbidity. The mixture was shaken for a further 10 minutes and allowed to stand. The title compound (I) crystallizes on standing for 6 h. The separated crystals were filtered, washed with cold water and recrystallized from ethanol. Yield: 1.34 g (95%). M.p. 485-486 K.

Refinement top

All hydrogen atoms were located from the difference Fourier map and refined freely, N—H = 0.820 (19) - 0.957 (19) Å and C–H = 0.945 (19) - 1.005 (18) Å.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with atom labels and 50% probability ellipsoids for non-H atoms.
[Figure 2] Fig. 2. The crystal packing of (I), viewed down the b axis, showing the molecules are linked along the c axis. Hydrogen bonds are shown in as dashed lines.
(E)-1-(4-Fluorophenyl)ethan-1-one semicarbazone top
Crystal data top
C9H10FN3OF(000) = 408
Mr = 195.20Dx = 1.428 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 5018 reflections
a = 18.8207 (3) Åθ = 4.2–38.8°
b = 6.6387 (1) ŵ = 0.11 mm1
c = 7.3074 (1) ÅT = 100 K
β = 95.887 (1)°Needle, colourless
V = 908.21 (2) Å30.30 × 0.10 × 0.08 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
3998 independent reflections
Radiation source: fine-focus sealed tube2766 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
ϕ and ω scansθmax = 35.0°, θmin = 1.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 2930
Tmin = 0.876, Tmax = 0.991k = 1010
17523 measured reflectionsl = 711
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.151H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.078P)2 + 0.1557P]
where P = (Fo2 + 2Fc2)/3
3998 reflections(Δ/σ)max < 0.001
167 parametersΔρmax = 0.51 e Å3
0 restraintsΔρmin = 0.30 e Å3
Crystal data top
C9H10FN3OV = 908.21 (2) Å3
Mr = 195.20Z = 4
Monoclinic, P21/cMo Kα radiation
a = 18.8207 (3) ŵ = 0.11 mm1
b = 6.6387 (1) ÅT = 100 K
c = 7.3074 (1) Å0.30 × 0.10 × 0.08 mm
β = 95.887 (1)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
3998 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
2766 reflections with I > 2σ(I)
Tmin = 0.876, Tmax = 0.991Rint = 0.033
17523 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.151H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.51 e Å3
3998 reflectionsΔρmin = 0.30 e Å3
167 parameters
Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.

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.

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 > 2sigma(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 (Å2) top
xyzUiso*/Ueq
F10.50077 (4)0.48694 (11)0.79001 (10)0.02274 (17)
O10.01336 (4)0.50372 (12)0.73484 (10)0.01547 (16)
N10.16753 (5)0.50702 (12)0.66798 (11)0.01257 (16)
N20.09495 (5)0.50670 (13)0.62389 (11)0.01339 (17)
N30.08724 (5)0.50728 (15)0.93755 (12)0.01734 (19)
C10.31185 (5)0.59520 (16)0.76477 (14)0.01595 (19)
C20.38374 (6)0.59368 (17)0.82935 (14)0.0178 (2)
C30.43028 (5)0.49203 (16)0.72738 (15)0.01591 (19)
C40.40812 (6)0.39453 (17)0.56461 (14)0.0177 (2)
C50.33579 (5)0.39948 (17)0.50051 (13)0.01569 (19)
C60.28652 (5)0.49812 (14)0.60026 (13)0.01153 (17)
C70.20888 (5)0.49673 (14)0.53803 (13)0.01158 (17)
C80.05269 (5)0.50588 (15)0.76711 (13)0.01249 (18)
C90.18228 (6)0.48336 (16)0.33718 (13)0.01471 (19)
H1A0.2783 (8)0.667 (2)0.8362 (19)0.023 (4)*
H2A0.4017 (8)0.666 (3)0.943 (2)0.031 (4)*
H4A0.4422 (7)0.324 (2)0.4966 (19)0.021 (3)*
H5A0.3214 (7)0.328 (2)0.3860 (19)0.017 (3)*
H9A0.1565 (9)0.602 (3)0.303 (2)0.035 (4)*
H9B0.1536 (9)0.364 (3)0.317 (2)0.037 (5)*
H9C0.2216 (10)0.480 (2)0.254 (2)0.031 (5)*
H1N20.0681 (10)0.502 (2)0.505 (3)0.029 (4)*
H1N30.1329 (10)0.506 (2)0.947 (2)0.025 (4)*
H2N30.0643 (10)0.505 (2)1.027 (3)0.030 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
F10.0096 (3)0.0346 (4)0.0230 (3)0.0012 (2)0.0031 (2)0.0014 (3)
O10.0103 (3)0.0256 (4)0.0103 (3)0.0002 (3)0.0004 (2)0.0005 (3)
N10.0098 (3)0.0167 (4)0.0110 (3)0.0002 (3)0.0002 (3)0.0005 (3)
N20.0101 (3)0.0220 (4)0.0080 (3)0.0003 (3)0.0004 (3)0.0000 (3)
N30.0120 (4)0.0317 (5)0.0082 (3)0.0002 (3)0.0003 (3)0.0006 (3)
C10.0137 (4)0.0188 (5)0.0150 (4)0.0013 (4)0.0002 (3)0.0034 (3)
C20.0152 (4)0.0214 (5)0.0161 (4)0.0001 (4)0.0022 (3)0.0036 (4)
C30.0097 (4)0.0205 (5)0.0169 (4)0.0002 (3)0.0017 (3)0.0026 (3)
C40.0131 (4)0.0230 (5)0.0173 (4)0.0029 (4)0.0021 (3)0.0016 (4)
C50.0134 (4)0.0202 (5)0.0133 (4)0.0012 (3)0.0006 (3)0.0024 (3)
C60.0107 (4)0.0134 (4)0.0103 (4)0.0005 (3)0.0002 (3)0.0007 (3)
C70.0116 (4)0.0128 (4)0.0102 (4)0.0005 (3)0.0003 (3)0.0006 (3)
C80.0114 (4)0.0167 (4)0.0094 (4)0.0000 (3)0.0009 (3)0.0005 (3)
C90.0122 (4)0.0211 (5)0.0105 (4)0.0010 (4)0.0003 (3)0.0006 (3)
Geometric parameters (Å, º) top
F1—C31.3587 (12)C2—C31.3826 (15)
O1—C81.2413 (12)C2—H2A0.989 (17)
N1—C71.2900 (13)C3—C41.3805 (15)
N1—N21.3709 (12)C4—C51.3939 (14)
N2—C81.3779 (13)C4—H4A0.971 (14)
N2—H1N20.957 (19)C5—C61.3995 (14)
N3—C81.3446 (13)C5—H5A0.976 (14)
N3—H1N30.856 (18)C6—C71.4851 (13)
N3—H2N30.820 (19)C7—C91.5040 (13)
C1—C21.3866 (14)C9—H9A0.945 (19)
C1—C61.4037 (14)C9—H9B0.964 (18)
C1—H1A0.983 (14)C9—H9C1.005 (18)
C7—N1—N2119.27 (8)C4—C5—C6120.83 (9)
N1—N2—C8117.41 (8)C4—C5—H5A116.8 (8)
N1—N2—H1N2129.3 (10)C6—C5—H5A122.3 (8)
C8—N2—H1N2113.3 (10)C5—C6—C1118.42 (9)
C8—N3—H1N3117.6 (12)C5—C6—C7121.42 (8)
C8—N3—H2N3119.6 (13)C1—C6—C7120.14 (8)
H1N3—N3—H2N3122.7 (18)N1—C7—C6115.04 (8)
C2—C1—C6121.47 (9)N1—C7—C9123.77 (9)
C2—C1—H1A118.7 (8)C6—C7—C9121.19 (8)
C6—C1—H1A119.8 (8)O1—C8—N3123.76 (9)
C3—C2—C1118.04 (9)O1—C8—N2120.04 (9)
C3—C2—H2A120.6 (9)N3—C8—N2116.20 (9)
C1—C2—H2A121.4 (9)C7—C9—H9A108.5 (11)
F1—C3—C4118.48 (9)C7—C9—H9B108.7 (10)
F1—C3—C2118.77 (9)H9A—C9—H9B112.6 (16)
C4—C3—C2122.75 (10)C7—C9—H9C113.6 (11)
C3—C4—C5118.48 (10)H9A—C9—H9C104.5 (14)
C3—C4—H4A120.7 (8)H9B—C9—H9C109.0 (14)
C5—C4—H4A120.8 (8)
C7—N1—N2—C8176.26 (9)C2—C1—C6—C7177.96 (9)
C6—C1—C2—C30.43 (16)N2—N1—C7—C6179.99 (8)
C1—C2—C3—F1179.17 (10)N2—N1—C7—C90.23 (14)
C1—C2—C3—C40.56 (17)C5—C6—C7—N1150.01 (10)
F1—C3—C4—C5179.90 (9)C1—C6—C7—N128.31 (13)
C2—C3—C4—C50.17 (17)C5—C6—C7—C929.77 (14)
C3—C4—C5—C61.05 (16)C1—C6—C7—C9151.91 (10)
C4—C5—C6—C11.16 (15)N1—N2—C8—O1179.35 (9)
C4—C5—C6—C7177.18 (9)N1—N2—C8—N30.57 (13)
C2—C1—C6—C50.41 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H1N2···O1i0.96 (2)1.94 (2)2.8998 (11)179.2 (18)
N3—H2N3···O1ii0.82 (2)2.07 (2)2.8901 (12)176 (2)
C2—H2A···Cg1iii0.989 (17)2.927 (18)3.7250 (12)138.5 (12)
C5—H5A···Cg1iv0.976 (14)2.825 (13)3.6505 (11)142.8 (10)
Symmetry codes: (i) x, y+1, z+1; (ii) x, y+1, z+2; (iii) x, y+1/2, z1/2; (iv) x, y1/2, z3/2.

Experimental details

Crystal data
Chemical formulaC9H10FN3O
Mr195.20
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)18.8207 (3), 6.6387 (1), 7.3074 (1)
β (°) 95.887 (1)
V3)908.21 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.30 × 0.10 × 0.08
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.876, 0.991
No. of measured, independent and
observed [I > 2σ(I)] reflections
17523, 3998, 2766
Rint0.033
(sin θ/λ)max1)0.807
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.151, 1.07
No. of reflections3998
No. of parameters167
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.51, 0.30

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H1N2···O1i0.96 (2)1.94 (2)2.8998 (11)179.2 (18)
N3—H2N3···O1ii0.82 (2)2.07 (2)2.8901 (12)176 (2)
C2—H2A···Cg1iii0.989 (17)2.927 (18)3.7250 (12)138.5 (12)
C5—H5A···Cg1iv0.976 (14)2.825 (13)3.6505 (11)142.8 (10)
Symmetry codes: (i) x, y+1, z+1; (ii) x, y+1, z+2; (iii) x, y+1/2, z1/2; (iv) x, y1/2, z3/2.
 

Footnotes

Thomson Reuters ResearcherID: A-3561-2009.

§Thomson Reuters ResearcherID: A-5523-2009.

Acknowledgements

HKF thanks Universiti Sains Malaysia for the Research University Golden Goose Grant No. 1001/PFIZIK/811012. CSY thanks the Malaysian Government and Universiti Sains Malaysia for the award of the post of Research Officer under the Science Fund grant No. 305/PFIZIK/613312. AMI is grateful to the Head of the Department of Chemistry and the Director, NITK, Surathkal, India, for providing research facilities.

References

First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
First citationBruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationChandra, S. & Gupta, L. K. (2005). Spectrochim. Acta Part A, 62, 1089–1094.  CrossRef Google Scholar
First citationCosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationFun, H.-K., Chantrapromma, S., Sujith, K. V. & Kalluraya, B. (2009a). Acta Cryst. E65, o445.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationFun, H.-K., Goh, J. H., Padaki, M., Malladi, S. & Isloor, A. M. (2009b). Acta Cryst. E65, o1591–o1592.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationFurniss, B. S., Hannaford, A. J., Rogers, V., Smith, P. W. G. & Tatchell, A. R. (1978). Vogel's Textbook of Practical Organic Chemistry, 4th ed., p. 1112. London: ELBS.  Google Scholar
First citationJain, V. K., Handa, A., Pandya, R., Shrivastav, P. & Agrawal, Y. K. (2002). React. Funct. Polym. 51, 101–110.  Web of Science CrossRef CAS Google Scholar
First citationPilgram, K. H. G. (1978). US Patent No. 4 108 399.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWarren, J. D., Woodward, D. L. & Hargreaves, R. T. (1977). J. Med. Chem. 20, 1520–1521.  CrossRef CAS PubMed Web of Science Google Scholar
First citationYogeeswari, P., Sriram, D., Pandeya, S. N. & Stables, J. P. (2004). Farmaco, 59, 609–613.  CrossRef PubMed CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 7| July 2009| Pages o1619-o1620
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds