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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

4-[(9-Ethyl-9H-carbazol-3-yl)imino­meth­yl]phenol

aNortheast China Electric Power University Personnel, Jilin 132012, People's Republic of China
*Correspondence e-mail: songzhulin@hotmail.com

(Received 14 October 2010; accepted 9 November 2010; online 17 November 2010)

In the title compound, C21H18N2O, the dihedral angle between the phenol ring and the carbazole system is 39.34 (2)°. Inter­molecular O—H⋯N hydrogen bonds and C—H⋯π and ππ inter­actions [centroid–centroid distances = 3.426 (2) and 3.768 (2) Å] stabilize the crystal structure.

Related literature

For polar organic mol­ecules as components of non-linear optical, electro-optical, photorefractive and optical-limiting materials, see: Nalwa & Miyata (1997[Nalwa, H. S. & Miyata, S. (1997). Nonlinear Optics of Organic Molecules and Polymers, p. 885. Boca Raton: CRC Press.]); Kuzyk & Dirk (1998[Kuzyk, M. C. & Dirk, C. W. (1998). Characterization Techniques and Tabulations for Organic Nonlinear Optical Materials, p. 894. New York: Marcel Dekker Inc.]); Nesterov et al. (2002[Nesterov, V. N., Montoya, N. G., Antipin, M. Yu., Sanghadasa, M., Clark, R. D. & Timofeeva, T. V. (2002). Acta Cryst. C58, o72-o75.]).

[Scheme 1]

Experimental

Crystal data
  • C21H18N2O

  • Mr = 314.37

  • Orthorhombic, P b c a

  • a = 13.386 (6) Å

  • b = 9.247 (4) Å

  • c = 26.443 (10) Å

  • V = 3273 (2) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 295 K

  • 0.25 × 0.20 × 0.15 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • 21605 measured reflections

  • 2878 independent reflections

  • 1615 reflections with I > 2σ(I)

  • Rint = 0.081

  • 3 standard reflections every 100 reflections intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.050

  • wR(F2) = 0.140

  • S = 1.02

  • 2878 reflections

  • 218 parameters

  • H-atom parameters constrained

  • Δρmax = 0.18 e Å−3

  • Δρmin = −0.18 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg2 is the centroid of the C3–C8 ring.

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1⋯N2i 0.82 2.09 2.842 (3) 153
C1—H1ACg2ii 0.96 2.77 3.698 (2) 162
Symmetry codes: (i) [-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (ii) [-x+{\script{3\over 2}}, y-{\script{1\over 2}}, z].

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: NRCVAX (Gabe et al., 1989[Gabe, E. J., Le Page, Y., Charland, J.-P., Lee, F. L. & White, P. S. (1989). J. Appl. Cryst. 22, 384-387.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Polar organic molecules as components of NLO, electro-optical, photorefractive and optical-limiting materials have been under intensive investigation (Nalwa & Miyata, 1997; Kuzyk & Dirk, 1998; Nesterov et al., 2002). Many N-ethylcarbazole derivatives have been studied for this purpose. In this paper, we describe the synthesis and structure determination of the title compound.

In the title compound, atoms O1, C15, N2 lie in the plane of phenyl ring C16—C21 (p1) with the largest deviation of 0.002 (3) Å for C16. The atoms of the carbazole ring together with C2 and N2 form a plane (p2) for which the largest deviation is 0.068 (1) Å for C5. The fragment C11,N2, C15,C16,C17 is coplanar (p3). The dihedral angles formed by p1 with p2 and p3 are 39.34 (2) and 6.01 (2)°, respectively. The dihedral angle between p2 and p3 is 42.21 (3)°.

In the lattice, ππ and C—H···π interactions occur [Cg1···Cg1i = 3.426 (2), Cg2···Cg3i = 3.768 (2) Å, C1···Cg2ii = 3.698 (2) Å, H1A···Cg2ii = 2.77 Å, symmetry codes: i 1 - x, -y, 1 - z; ii 3/2 - x, -1/2 + y, z. Cg1, Cg2, Cg3 refer to ring N1—C3—C8—C9—C14 and phenyl rings C3—C8 and C9—C14, respectively]. In addition, an intermolecular hydrogen bond (Table 1) along with the C—H···π and ππ interactions stabilizes the crystal structure. The H-bond results in infinite chains along [010].

Related literature top

For polar organic molecules as components of non-linear optical, electro-optical, photorefractive and optical-limiting materials, see: Nalwa & Miyata (1997); Kuzyk & Dirk (1998); Nesterov et al. (2002).

Experimental top

The title compound was synthesized by reaction of 9-ethyl-carbazol-3-amine (0.420 g, 0.002 mol) and 4-hydroxybenzaldehyde (0.244 g, 0.002 mol) in ethanol (50 ml) under stirring for 5 h at room temperature. Single crystals suitable for x-ray measurements were obtained by recrystallization from ethyl acetate at room temperature.

Refinement top

H atoms were fixed geometrically and allowed to ride on their attached atoms, with C—H distances=0.93–0.96 Å, O—H distance=0.82 Å and with Uiso=1.2–1.5Ueq.

Structure description top

Polar organic molecules as components of NLO, electro-optical, photorefractive and optical-limiting materials have been under intensive investigation (Nalwa & Miyata, 1997; Kuzyk & Dirk, 1998; Nesterov et al., 2002). Many N-ethylcarbazole derivatives have been studied for this purpose. In this paper, we describe the synthesis and structure determination of the title compound.

In the title compound, atoms O1, C15, N2 lie in the plane of phenyl ring C16—C21 (p1) with the largest deviation of 0.002 (3) Å for C16. The atoms of the carbazole ring together with C2 and N2 form a plane (p2) for which the largest deviation is 0.068 (1) Å for C5. The fragment C11,N2, C15,C16,C17 is coplanar (p3). The dihedral angles formed by p1 with p2 and p3 are 39.34 (2) and 6.01 (2)°, respectively. The dihedral angle between p2 and p3 is 42.21 (3)°.

In the lattice, ππ and C—H···π interactions occur [Cg1···Cg1i = 3.426 (2), Cg2···Cg3i = 3.768 (2) Å, C1···Cg2ii = 3.698 (2) Å, H1A···Cg2ii = 2.77 Å, symmetry codes: i 1 - x, -y, 1 - z; ii 3/2 - x, -1/2 + y, z. Cg1, Cg2, Cg3 refer to ring N1—C3—C8—C9—C14 and phenyl rings C3—C8 and C9—C14, respectively]. In addition, an intermolecular hydrogen bond (Table 1) along with the C—H···π and ππ interactions stabilizes the crystal structure. The H-bond results in infinite chains along [010].

For polar organic molecules as components of non-linear optical, electro-optical, photorefractive and optical-limiting materials, see: Nalwa & Miyata (1997); Kuzyk & Dirk (1998); Nesterov et al. (2002).

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: NRCVAX (Gabe et al., 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The structure of the title compound showing 30% probability displacement ellipsoids and the atom-numbering scheme.
4-[(9-Ethyl-9H-carbazol-3-yl)iminomethyl]phenol top
Crystal data top
C21H18N2OF(000) = 1328
Mr = 314.37Dx = 1.276 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 25 reflections
a = 13.386 (6) Åθ = 4–14°
b = 9.247 (4) ŵ = 0.08 mm1
c = 26.443 (10) ÅT = 295 K
V = 3273 (2) Å3Block, brown
Z = 80.25 × 0.20 × 0.15 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.081
Radiation source: fine-focus sealed tubeθmax = 25.0°, θmin = 1.5°
Graphite monochromatorh = 1515
ω scansk = 1010
21605 measured reflectionsl = 3128
2878 independent reflections3 standard reflections every 100 reflections
1615 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.140 w = 1/[σ2(Fo2) + (0.0568P)2 + 0.6129P]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max < 0.001
2878 reflectionsΔρmax = 0.18 e Å3
218 parametersΔρmin = 0.18 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0037 (8)
Crystal data top
C21H18N2OV = 3273 (2) Å3
Mr = 314.37Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 13.386 (6) ŵ = 0.08 mm1
b = 9.247 (4) ÅT = 295 K
c = 26.443 (10) Å0.25 × 0.20 × 0.15 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.081
21605 measured reflections3 standard reflections every 100 reflections
2878 independent reflections intensity decay: none
1615 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.140H-atom parameters constrained
S = 1.02Δρmax = 0.18 e Å3
2878 reflectionsΔρmin = 0.18 e Å3
218 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
O10.61757 (15)0.7932 (2)0.83217 (7)0.0802 (7)
H10.56240.83160.83140.096*
N10.64140 (15)0.0252 (2)0.47293 (8)0.0538 (6)
N20.58786 (17)0.3455 (2)0.64785 (8)0.0580 (6)
C10.7978 (2)0.0332 (4)0.42951 (13)0.0866 (10)
H1A0.83970.11230.41930.130*
H1B0.83430.02920.45190.130*
H1C0.77720.02020.40020.130*
C20.7074 (2)0.0908 (3)0.45633 (11)0.0639 (8)
H2B0.67110.15470.43380.077*
H2C0.72850.14680.48550.077*
C30.57518 (18)0.0966 (3)0.44114 (10)0.0509 (7)
C40.5568 (2)0.0753 (3)0.39037 (11)0.0635 (8)
H4A0.58920.00240.37250.076*
C50.4897 (2)0.1644 (3)0.36707 (12)0.0710 (9)
H5A0.47670.15230.33280.085*
C60.4407 (2)0.2721 (3)0.39335 (12)0.0692 (8)
H6A0.39530.33100.37650.083*
C70.45795 (19)0.2937 (3)0.44390 (11)0.0605 (7)
H7A0.42410.36580.46140.073*
C80.52679 (18)0.2060 (3)0.46856 (10)0.0473 (6)
C90.56752 (17)0.2025 (3)0.51875 (9)0.0462 (6)
C100.55122 (17)0.2834 (3)0.56227 (10)0.0509 (7)
H10A0.50300.35580.56240.061*
C110.60673 (19)0.2563 (3)0.60528 (10)0.0518 (7)
C120.6761 (2)0.1429 (3)0.60559 (10)0.0576 (7)
H12A0.71220.12420.63490.069*
C130.69205 (19)0.0585 (3)0.56350 (11)0.0579 (7)
H13A0.73760.01740.56420.069*
C140.63826 (18)0.0899 (3)0.51982 (10)0.0492 (7)
C150.6605 (2)0.3883 (3)0.67601 (11)0.0613 (8)
H15A0.72440.35390.66920.074*
C160.6471 (2)0.4883 (3)0.71814 (10)0.0593 (7)
C170.7279 (2)0.5339 (3)0.74665 (11)0.0716 (9)
H17A0.79070.49470.74040.086*
C180.7171 (2)0.6370 (4)0.78447 (11)0.0741 (9)
H18A0.77240.66750.80290.089*
C190.6242 (2)0.6938 (3)0.79452 (10)0.0624 (8)
C200.5425 (2)0.6490 (3)0.76697 (11)0.0685 (8)
H20A0.47950.68660.77390.082*
C210.5548 (2)0.5481 (3)0.72916 (11)0.0684 (8)
H21A0.49940.51920.71050.082*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0871 (15)0.0854 (15)0.0680 (13)0.0061 (12)0.0009 (11)0.0171 (12)
N10.0561 (13)0.0473 (13)0.0581 (15)0.0069 (11)0.0047 (11)0.0006 (11)
N20.0668 (15)0.0555 (14)0.0516 (14)0.0026 (12)0.0064 (12)0.0043 (12)
C10.0619 (19)0.094 (2)0.104 (3)0.0178 (18)0.0165 (18)0.007 (2)
C20.0691 (18)0.0502 (17)0.072 (2)0.0120 (15)0.0020 (15)0.0050 (15)
C30.0504 (15)0.0465 (15)0.0558 (18)0.0040 (13)0.0049 (14)0.0011 (14)
C40.0670 (18)0.0630 (19)0.061 (2)0.0038 (16)0.0000 (15)0.0093 (16)
C50.074 (2)0.080 (2)0.0587 (19)0.0030 (18)0.0070 (16)0.0039 (17)
C60.0697 (19)0.073 (2)0.065 (2)0.0118 (16)0.0099 (16)0.0089 (17)
C70.0571 (17)0.0580 (18)0.066 (2)0.0058 (14)0.0018 (15)0.0063 (16)
C80.0452 (14)0.0447 (15)0.0521 (17)0.0003 (12)0.0060 (12)0.0034 (13)
C90.0459 (14)0.0403 (14)0.0524 (17)0.0001 (12)0.0066 (12)0.0055 (13)
C100.0479 (15)0.0446 (15)0.0601 (17)0.0040 (12)0.0078 (14)0.0049 (14)
C110.0564 (16)0.0490 (16)0.0499 (17)0.0001 (13)0.0109 (14)0.0028 (14)
C120.0619 (17)0.0568 (17)0.0540 (18)0.0030 (15)0.0014 (14)0.0062 (15)
C130.0585 (17)0.0518 (16)0.0633 (19)0.0102 (13)0.0003 (15)0.0057 (15)
C140.0484 (15)0.0434 (15)0.0557 (18)0.0011 (13)0.0075 (13)0.0001 (14)
C150.0726 (19)0.0539 (17)0.0573 (18)0.0054 (16)0.0096 (16)0.0085 (15)
C160.0678 (19)0.0598 (18)0.0502 (18)0.0014 (15)0.0049 (15)0.0060 (14)
C170.063 (2)0.081 (2)0.071 (2)0.0010 (17)0.0020 (16)0.0031 (19)
C180.072 (2)0.087 (2)0.063 (2)0.0078 (18)0.0039 (16)0.0078 (18)
C190.075 (2)0.0636 (18)0.0484 (17)0.0049 (17)0.0060 (16)0.0014 (15)
C200.069 (2)0.075 (2)0.0622 (19)0.0049 (16)0.0005 (16)0.0105 (17)
C210.068 (2)0.078 (2)0.0593 (19)0.0006 (17)0.0005 (15)0.0099 (17)
Geometric parameters (Å, º) top
O1—C191.358 (3)C8—C91.435 (3)
O1—H10.8200C9—C101.390 (3)
N1—C141.377 (3)C9—C141.407 (3)
N1—C31.389 (3)C10—C111.382 (3)
N1—C21.457 (3)C10—H10A0.9300
N2—C151.288 (3)C11—C121.401 (3)
N2—C111.418 (3)C12—C131.376 (3)
C1—C21.500 (4)C12—H12A0.9300
C1—H1A0.9600C13—C141.392 (3)
C1—H1B0.9600C13—H13A0.9300
C1—H1C0.9600C15—C161.459 (4)
C2—H2B0.9700C15—H15A0.9300
C2—H2C0.9700C16—C171.384 (4)
C3—C41.379 (3)C16—C211.385 (4)
C3—C81.403 (3)C17—C181.389 (4)
C4—C51.366 (4)C17—H17A0.9300
C4—H4A0.9300C18—C191.376 (4)
C5—C61.380 (4)C18—H18A0.9300
C5—H5A0.9300C19—C201.378 (4)
C6—C71.371 (4)C20—C211.377 (4)
C6—H6A0.9300C20—H20A0.9300
C7—C81.390 (3)C21—H21A0.9300
C7—H7A0.9300
C19—O1—H1109.5C14—C9—C8106.9 (2)
C14—N1—C3108.6 (2)C11—C10—C9120.0 (2)
C14—N1—C2127.6 (2)C11—C10—H10A120.0
C3—N1—C2123.7 (2)C9—C10—H10A120.0
C15—N2—C11120.2 (2)C10—C11—C12119.8 (2)
C2—C1—H1A109.5C10—C11—N2116.9 (2)
C2—C1—H1B109.5C12—C11—N2123.3 (2)
H1A—C1—H1B109.5C13—C12—C11121.5 (2)
C2—C1—H1C109.5C13—C12—H12A119.2
H1A—C1—H1C109.5C11—C12—H12A119.2
H1B—C1—H1C109.5C12—C13—C14118.2 (2)
N1—C2—C1111.7 (2)C12—C13—H13A120.9
N1—C2—H2B109.3C14—C13—H13A120.9
C1—C2—H2B109.3N1—C14—C13129.8 (2)
N1—C2—H2C109.3N1—C14—C9108.9 (2)
C1—C2—H2C109.3C13—C14—C9121.3 (2)
H2B—C2—H2C107.9N2—C15—C16122.9 (3)
C4—C3—N1129.4 (2)N2—C15—H15A118.5
C4—C3—C8121.6 (3)C16—C15—H15A118.5
N1—C3—C8109.0 (2)C17—C16—C21117.5 (3)
C5—C4—C3118.0 (3)C17—C16—C15120.8 (3)
C5—C4—H4A121.0C21—C16—C15121.6 (3)
C3—C4—H4A121.0C16—C17—C18121.3 (3)
C4—C5—C6121.4 (3)C16—C17—H17A119.4
C4—C5—H5A119.3C18—C17—H17A119.4
C6—C5—H5A119.3C19—C18—C17119.7 (3)
C7—C6—C5121.1 (3)C19—C18—H18A120.2
C7—C6—H6A119.5C17—C18—H18A120.2
C5—C6—H6A119.5O1—C19—C18117.3 (3)
C6—C7—C8118.9 (3)O1—C19—C20122.6 (3)
C6—C7—H7A120.5C18—C19—C20120.0 (3)
C8—C7—H7A120.5C21—C20—C19119.5 (3)
C7—C8—C3119.0 (3)C21—C20—H20A120.2
C7—C8—C9134.3 (2)C19—C20—H20A120.2
C3—C8—C9106.6 (2)C20—C21—C16122.0 (3)
C10—C9—C14119.2 (2)C20—C21—H21A119.0
C10—C9—C8133.9 (2)C16—C21—H21A119.0
Hydrogen-bond geometry (Å, º) top
Cg2 is the centroid of the C3–C8 ring.
D—H···AD—HH···AD···AD—H···A
O1—H1···N2i0.822.092.842 (3)153
C1—H1A···Cg2ii0.962.773.698 (2)162
Symmetry codes: (i) x+1, y+1/2, z+3/2; (ii) x+3/2, y1/2, z.

Experimental details

Crystal data
Chemical formulaC21H18N2O
Mr314.37
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)295
a, b, c (Å)13.386 (6), 9.247 (4), 26.443 (10)
V3)3273 (2)
Z8
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.25 × 0.20 × 0.15
Data collection
DiffractometerEnraf–Nonius CAD-4
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
21605, 2878, 1615
Rint0.081
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.140, 1.02
No. of reflections2878
No. of parameters218
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.18, 0.18

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), NRCVAX (Gabe et al., 1989), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
Cg2 is the centroid of the C3–C8 ring.
D—H···AD—HH···AD···AD—H···A
O1—H1···N2i0.822.092.842 (3)153
C1—H1A···Cg2ii0.962.773.698 (2)162
Symmetry codes: (i) x+1, y+1/2, z+3/2; (ii) x+3/2, y1/2, z.
 

Acknowledgements

The authors would like to thank the Jilin Province Science and Technology Development Plan for support.

References

First citationEnraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationGabe, E. J., Le Page, Y., Charland, J.-P., Lee, F. L. & White, P. S. (1989). J. Appl. Cryst. 22, 384–387.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationKuzyk, M. C. & Dirk, C. W. (1998). Characterization Techniques and Tabulations for Organic Nonlinear Optical Materials, p. 894. New York: Marcel Dekker Inc.  Google Scholar
First citationNalwa, H. S. & Miyata, S. (1997). Nonlinear Optics of Organic Molecules and Polymers, p. 885. Boca Raton: CRC Press.  Google Scholar
First citationNesterov, V. N., Montoya, N. G., Antipin, M. Yu., Sanghadasa, M., Clark, R. D. & Timofeeva, T. V. (2002). Acta Cryst. C58, o72–o75.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals 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
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds