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ISSN: 2056-9890

3,5-Bis[(pyridin-4-yl)meth­­oxy]benzoic acid

aJinhua Professional Technical College, No. 1188 Wuzhou Street, Jinhua, Zhejiang 321017, People's Republic of China, and bZhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004, People's Republic of China
*Correspondence e-mail: jh_ll@126.com

(Received 12 November 2012; accepted 3 December 2012; online 12 December 2012)

Single crystals of the title compound, C19H16N2O4, were obtained under hydro­thermal conditions by an unintended recrystallization of the employed microcrystalline starting material. The [(pyridin-4-yl)meth­oxy]benzoic acid unit is nearly planar, with a maximum deviation from the least-squares plane of 0.194 (2) Å. This plane is inclined by 35.82 (6)° to that defined by the second (pyridin-4-yl)meth­oxy group [in which the largest deviation from the least-squares plane is 0.013 (2) Å]. In the crystal, mol­ecules are linked by O—H⋯N hydrogen bonds involving the acid hy­droxy group and a pyridine N atom into chains parallel to [-201].

Related literature

For compounds with metal-organic framework structures derived from the title compound, see: Xu et al. (2009[Xu, G. J., Zhao, Y. H., Shao, K. Z., Lan, Y. Q., Wang, X. L., Su, Z. M. & Yan, L. K. (2009). CrystEngComm, 11, 1842-1847.]).

[Scheme 1]

Experimental

Crystal data
  • C19H16N2O4

  • Mr = 336.34

  • Monoclinic, P 21 /c

  • a = 11.1523 (6) Å

  • b = 11.2120 (6) Å

  • c = 13.9255 (7) Å

  • β = 102.827 (3)°

  • V = 1697.79 (15) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 296 K

  • 0.38 × 0.33 × 0.21 mm

Data collection
  • Bruker SMART CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2006[Bruker (2006). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.965, Tmax = 0.980

  • 25948 measured reflections

  • 3936 independent reflections

  • 2980 reflections with I > 2σ(I)

  • Rint = 0.025

Refinement
  • R[F2 > 2σ(F2)] = 0.046

  • wR(F2) = 0.132

  • S = 1.04

  • 3936 reflections

  • 226 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.26 e Å−3

  • Δρmin = −0.25 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O2—H1A⋯N2i 0.85 1.83 2.6736 (16) 171
Symmetry code: (i) [x+1, -y+{\script{3\over 2}}, z+{\script{1\over 2}}].

Data collection: SMART (Bruker, 2006[Bruker (2006). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2006[Bruker (2006). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

MOFs derived from the 3,5-bis(pyridin-4-ylmethoxy)benzoic acid ligand have been synthesized recently (Xu et al., 2009). During hydrothermal syntheses intended for crystal growth of related systems, crystals of the educt 3,5-bis(pyridin-4-yl-methoxy)benzoic acid, (I), have been unexpectedly obtained.

The molecular structure of (I) is presented in Fig. 1. Atoms O1—O4, C1—C6, C12—C19 and N2 are nearly coplanar (r.m.s. deviation = 0.098 Å; largest deviation from the least-squares plane 0.194 (2) Å); atoms C7—C11, C18 and N1 of the second pyridyl moiety are in another plane (r.m.s. deviation = 0.003 Å; largest deviation from the least-squares plane 0.013 (2) Å). The dihedral angle between the two planes is 35.82 (6)°.

The carboxylic O—H group and neighbouring pyridyl N atoms are involved in O—H···N hydrogen-bonding interactions (Table 1), forming chains extending parallel to [201] (Fig. 2). There are no significant π···π interactions between the aromatic planes of adjacent chains.

Related literature top

For compounds with metal-organic framework structures derived from the title compound, see: Xu et al. (2009).

Experimental top

3,5-bis(pyridin-4-yl-methoxy)benzoic acid was obtained commercially. A mixture of 3,5-bis(pyridin-4-yl-methoxy)benzoic acid (0.5 mmol), CdCl2.2.5H2O (0.25 mmol), and NaOH (0.5 mmol) in H2O (16 ml) was sealed in a 25 ml stainless steel reactor with a telflon liner and heated at 433 K for 72 h, and then cooled to room temperature at a speed of 5 Kh-1. Colourless single crystals of (I) were obtained by slow evaporation of the filtrate over a few days.

Refinement top

Carbon-bound H-atoms were positioned geometrically and included in the refinement using a riding model [C—H 0.93 Å (aromatic), 0.97 Å (methylene); Uiso(H) = 1.2Ueq(C)]. The oxygen-bound H-atom was located in a difference Fourier map and refined with an O—H distance restrained to 0.85 Å [Uiso(H) = 1.2Ueq(O)].

Structure description top

MOFs derived from the 3,5-bis(pyridin-4-ylmethoxy)benzoic acid ligand have been synthesized recently (Xu et al., 2009). During hydrothermal syntheses intended for crystal growth of related systems, crystals of the educt 3,5-bis(pyridin-4-yl-methoxy)benzoic acid, (I), have been unexpectedly obtained.

The molecular structure of (I) is presented in Fig. 1. Atoms O1—O4, C1—C6, C12—C19 and N2 are nearly coplanar (r.m.s. deviation = 0.098 Å; largest deviation from the least-squares plane 0.194 (2) Å); atoms C7—C11, C18 and N1 of the second pyridyl moiety are in another plane (r.m.s. deviation = 0.003 Å; largest deviation from the least-squares plane 0.013 (2) Å). The dihedral angle between the two planes is 35.82 (6)°.

The carboxylic O—H group and neighbouring pyridyl N atoms are involved in O—H···N hydrogen-bonding interactions (Table 1), forming chains extending parallel to [201] (Fig. 2). There are no significant π···π interactions between the aromatic planes of adjacent chains.

For compounds with metal-organic framework structures derived from the title compound, see: Xu et al. (2009).

Computing details top

Data collection: SMART (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. A view of the one-dimensional chain-like structure of (I).
3,5-Bis[(pyridin-4-yl)methoxy]benzoic acid top
Crystal data top
C19H16N2O4F(000) = 704
Mr = 336.34Dx = 1.316 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 9997 reflections
a = 11.1523 (6) Åθ = 1.9–27.6°
b = 11.2120 (6) ŵ = 0.09 mm1
c = 13.9255 (7) ÅT = 296 K
β = 102.827 (3)°Block, colourless
V = 1697.79 (15) Å30.38 × 0.33 × 0.21 mm
Z = 4
Data collection top
Bruker SMART CCD
diffractometer
3936 independent reflections
Radiation source: fine-focus sealed tube2980 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
ω scansθmax = 27.6°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Bruker, 2006)
h = 1314
Tmin = 0.965, Tmax = 0.980k = 1414
25948 measured reflectionsl = 1818
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)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.132H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0639P)2 + 0.2876P]
where P = (Fo2 + 2Fc2)/3
3936 reflections(Δ/σ)max = 0.001
226 parametersΔρmax = 0.26 e Å3
1 restraintΔρmin = 0.25 e Å3
Crystal data top
C19H16N2O4V = 1697.79 (15) Å3
Mr = 336.34Z = 4
Monoclinic, P21/cMo Kα radiation
a = 11.1523 (6) ŵ = 0.09 mm1
b = 11.2120 (6) ÅT = 296 K
c = 13.9255 (7) Å0.38 × 0.33 × 0.21 mm
β = 102.827 (3)°
Data collection top
Bruker SMART CCD
diffractometer
3936 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2006)
2980 reflections with I > 2σ(I)
Tmin = 0.965, Tmax = 0.980Rint = 0.025
25948 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0461 restraint
wR(F2) = 0.132H-atom parameters constrained
S = 1.04Δρmax = 0.26 e Å3
3936 reflectionsΔρmin = 0.25 e Å3
226 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
N10.68638 (16)0.22020 (13)0.06179 (12)0.0777 (4)
N20.01294 (12)0.70984 (13)0.08773 (10)0.0647 (4)
O10.89003 (10)0.51053 (12)0.36115 (10)0.0864 (4)
O20.78235 (10)0.67629 (10)0.32201 (9)0.0756 (4)
H1A0.84580.70980.35650.091*
O30.61952 (9)0.19740 (9)0.14886 (9)0.0684 (3)
O40.38875 (8)0.55619 (8)0.10585 (7)0.0537 (3)
C10.69258 (11)0.49686 (12)0.25395 (9)0.0448 (3)
C20.70848 (11)0.37573 (12)0.23705 (10)0.0482 (3)
H2A0.78070.33680.26720.058*
C30.61508 (12)0.31505 (12)0.17484 (10)0.0495 (3)
C40.50609 (12)0.37228 (12)0.13026 (10)0.0491 (3)
H4A0.44320.33020.08900.059*
C50.49235 (11)0.49207 (12)0.14796 (9)0.0441 (3)
C60.58568 (11)0.55589 (12)0.21024 (9)0.0447 (3)
H6A0.57610.63660.22210.054*
C70.79339 (18)0.16440 (16)0.08353 (15)0.0779 (5)
H7A0.86160.20480.07200.093*
C80.81162 (14)0.05037 (14)0.12215 (12)0.0618 (4)
H8A0.88920.01550.13480.074*
C90.71223 (12)0.00998 (12)0.14135 (9)0.0473 (3)
C100.59962 (14)0.04711 (14)0.11926 (11)0.0578 (4)
H10A0.52980.00940.13070.069*
C110.59181 (16)0.16036 (15)0.08012 (13)0.0687 (4)
H11A0.51510.19710.06570.082*
C120.00017 (14)0.59958 (16)0.11826 (12)0.0647 (4)
H12A0.06210.56830.16780.078*
C130.09988 (13)0.52908 (15)0.08048 (10)0.0558 (4)
H13A0.10480.45200.10400.067*
C140.19354 (11)0.57435 (12)0.00677 (9)0.0445 (3)
C150.18240 (13)0.68999 (13)0.02401 (10)0.0511 (3)
H15A0.24400.72430.07220.061*
C160.07743 (14)0.75435 (14)0.01820 (12)0.0612 (4)
H16A0.07000.83210.00310.073*
C170.79843 (12)0.56116 (13)0.31786 (11)0.0541 (3)
C180.72785 (12)0.13267 (12)0.18610 (11)0.0522 (3)
H18A0.74240.12730.25730.063*
H18B0.79760.17230.16910.063*
C190.29911 (11)0.49396 (12)0.03536 (10)0.0497 (3)
H19A0.26970.42580.06640.060*
H19B0.33590.46490.01710.060*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0886 (11)0.0541 (8)0.0904 (10)0.0016 (8)0.0201 (9)0.0160 (7)
N20.0505 (7)0.0672 (8)0.0686 (8)0.0100 (6)0.0036 (6)0.0160 (7)
O10.0504 (6)0.0758 (8)0.1111 (10)0.0056 (6)0.0290 (6)0.0171 (7)
O20.0566 (6)0.0573 (7)0.0939 (8)0.0075 (5)0.0237 (6)0.0146 (6)
O30.0498 (6)0.0426 (5)0.0982 (8)0.0087 (4)0.0150 (5)0.0135 (5)
O40.0401 (5)0.0459 (5)0.0648 (6)0.0070 (4)0.0104 (4)0.0112 (4)
C10.0367 (6)0.0487 (7)0.0453 (6)0.0037 (5)0.0014 (5)0.0028 (5)
C20.0371 (6)0.0481 (7)0.0538 (7)0.0041 (5)0.0016 (5)0.0013 (6)
C30.0427 (7)0.0416 (7)0.0598 (8)0.0021 (5)0.0017 (6)0.0033 (6)
C40.0365 (6)0.0461 (7)0.0585 (8)0.0002 (5)0.0030 (5)0.0074 (6)
C50.0352 (6)0.0446 (7)0.0489 (7)0.0030 (5)0.0014 (5)0.0028 (5)
C60.0415 (7)0.0406 (7)0.0484 (7)0.0010 (5)0.0022 (5)0.0041 (5)
C70.0740 (11)0.0671 (11)0.0956 (13)0.0193 (9)0.0255 (10)0.0133 (9)
C80.0506 (8)0.0611 (9)0.0731 (10)0.0059 (7)0.0121 (7)0.0047 (7)
C90.0500 (7)0.0447 (7)0.0442 (6)0.0053 (6)0.0044 (5)0.0015 (5)
C100.0510 (8)0.0553 (8)0.0660 (9)0.0029 (6)0.0107 (7)0.0058 (7)
C110.0667 (10)0.0596 (10)0.0772 (10)0.0100 (8)0.0107 (8)0.0104 (8)
C120.0496 (8)0.0758 (11)0.0586 (8)0.0018 (7)0.0094 (6)0.0037 (8)
C130.0458 (7)0.0594 (9)0.0556 (8)0.0010 (6)0.0027 (6)0.0052 (6)
C140.0368 (6)0.0499 (7)0.0444 (6)0.0030 (5)0.0038 (5)0.0013 (5)
C150.0459 (7)0.0497 (8)0.0533 (7)0.0037 (6)0.0014 (6)0.0009 (6)
C160.0577 (9)0.0513 (8)0.0718 (9)0.0105 (7)0.0083 (7)0.0068 (7)
C170.0425 (7)0.0551 (8)0.0578 (8)0.0030 (6)0.0037 (6)0.0074 (6)
C180.0453 (7)0.0486 (7)0.0569 (8)0.0060 (6)0.0008 (6)0.0031 (6)
C190.0370 (7)0.0485 (7)0.0571 (7)0.0037 (5)0.0036 (6)0.0084 (6)
Geometric parameters (Å, º) top
N1—C71.322 (2)C7—H7A0.9300
N1—C111.322 (2)C8—C91.375 (2)
N2—C121.325 (2)C8—H8A0.9300
N2—C161.330 (2)C9—C101.382 (2)
O1—C171.2066 (17)C9—C181.5043 (19)
O2—C171.3063 (18)C10—C111.377 (2)
O2—H1A0.8500C10—H10A0.9300
O3—C31.3716 (17)C11—H11A0.9300
O3—C181.4060 (16)C12—C131.373 (2)
O4—C51.3765 (14)C12—H12A0.9300
O4—C191.4192 (14)C13—C141.3879 (18)
C1—C61.3812 (17)C13—H13A0.9300
C1—C21.3964 (19)C14—C151.3798 (19)
C1—C171.4962 (17)C14—C191.4953 (17)
C2—C31.3776 (18)C15—C161.3897 (19)
C2—H2A0.9300C15—H15A0.9300
C3—C41.3926 (18)C16—H16A0.9300
C4—C51.3802 (19)C18—H18A0.9700
C4—H4A0.9300C18—H18B0.9700
C5—C61.3952 (17)C19—H19A0.9700
C6—H6A0.9300C19—H19B0.9700
C7—C81.384 (2)
C7—N1—C11115.73 (15)C9—C10—H10A120.3
C12—N2—C16117.75 (13)N1—C11—C10124.16 (16)
C17—O2—H1A110.9N1—C11—H11A117.9
C3—O3—C18118.52 (10)C10—C11—H11A117.9
C5—O4—C19115.70 (10)N2—C12—C13123.37 (14)
C6—C1—C2121.42 (11)N2—C12—H12A118.3
C6—C1—C17121.41 (12)C13—C12—H12A118.3
C2—C1—C17117.12 (11)C12—C13—C14119.14 (14)
C3—C2—C1118.66 (12)C12—C13—H13A120.4
C3—C2—H2A120.7C14—C13—H13A120.4
C1—C2—H2A120.7C15—C14—C13117.94 (12)
O3—C3—C2125.05 (12)C15—C14—C19124.19 (12)
O3—C3—C4113.87 (11)C13—C14—C19117.87 (12)
C2—C3—C4121.07 (12)C14—C15—C16118.82 (13)
C5—C4—C3119.29 (12)C14—C15—H15A120.6
C5—C4—H4A120.4C16—C15—H15A120.6
C3—C4—H4A120.4N2—C16—C15122.96 (14)
O4—C5—C4123.23 (11)N2—C16—H16A118.5
O4—C5—C6115.90 (11)C15—C16—H16A118.5
C4—C5—C6120.87 (11)O1—C17—O2123.51 (13)
C1—C6—C5118.69 (12)O1—C17—C1122.63 (14)
C1—C6—H6A120.7O2—C17—C1113.86 (12)
C5—C6—H6A120.7O3—C18—C9107.95 (11)
N1—C7—C8124.98 (16)O3—C18—H18A110.1
N1—C7—H7A117.5C9—C18—H18A110.1
C8—C7—H7A117.5O3—C18—H18B110.1
C9—C8—C7118.36 (15)C9—C18—H18B110.1
C9—C8—H8A120.8H18A—C18—H18B108.4
C7—C8—H8A120.8O4—C19—C14110.32 (11)
C8—C9—C10117.45 (13)O4—C19—H19A109.6
C8—C9—C18120.43 (13)C14—C19—H19A109.6
C10—C9—C18122.12 (12)O4—C19—H19B109.6
C11—C10—C9119.32 (14)C14—C19—H19B109.6
C11—C10—H10A120.3H19A—C19—H19B108.1
C6—C1—C2—C30.4 (2)C18—C9—C10—C11178.76 (14)
C17—C1—C2—C3176.99 (13)C7—N1—C11—C100.0 (3)
C18—O3—C3—C21.4 (2)C9—C10—C11—N10.1 (3)
C18—O3—C3—C4177.06 (13)C16—N2—C12—C131.3 (3)
C1—C2—C3—O3177.65 (14)N2—C12—C13—C140.3 (3)
C1—C2—C3—C40.7 (2)C12—C13—C14—C151.1 (2)
O3—C3—C4—C5177.79 (13)C12—C13—C14—C19177.87 (14)
C2—C3—C4—C50.8 (2)C13—C14—C15—C161.5 (2)
C19—O4—C5—C45.20 (19)C19—C14—C15—C16177.46 (13)
C19—O4—C5—C6174.18 (11)C12—N2—C16—C150.9 (2)
C3—C4—C5—O4178.92 (13)C14—C15—C16—N20.5 (2)
C3—C4—C5—C60.4 (2)C6—C1—C17—O1175.83 (15)
C2—C1—C6—C50.1 (2)C2—C1—C17—O16.8 (2)
C17—C1—C6—C5177.20 (12)C6—C1—C17—O24.3 (2)
O4—C5—C6—C1179.31 (11)C2—C1—C17—O2173.04 (13)
C4—C5—C6—C10.1 (2)C3—O3—C18—C9176.09 (13)
C11—N1—C7—C80.7 (3)C8—C9—C18—O3147.29 (14)
N1—C7—C8—C91.1 (3)C10—C9—C18—O333.63 (18)
C7—C8—C9—C100.9 (2)C5—O4—C19—C14178.29 (11)
C7—C8—C9—C18178.20 (15)C15—C14—C19—O43.97 (19)
C8—C9—C10—C110.3 (2)C13—C14—C19—O4177.08 (12)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H1A···N2i0.851.832.6736 (16)171
Symmetry code: (i) x+1, y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC19H16N2O4
Mr336.34
Crystal system, space groupMonoclinic, P21/c
Temperature (K)296
a, b, c (Å)11.1523 (6), 11.2120 (6), 13.9255 (7)
β (°) 102.827 (3)
V3)1697.79 (15)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.38 × 0.33 × 0.21
Data collection
DiffractometerBruker SMART CCD
Absorption correctionMulti-scan
(SADABS; Bruker, 2006)
Tmin, Tmax0.965, 0.980
No. of measured, independent and
observed [I > 2σ(I)] reflections
25948, 3936, 2980
Rint0.025
(sin θ/λ)max1)0.652
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.132, 1.04
No. of reflections3936
No. of parameters226
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.26, 0.25

Computer programs: SMART (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2006), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H1A···N2i0.851.832.6736 (16)170.9
Symmetry code: (i) x+1, y+3/2, z+1/2.
 

References

First citationBruker (2006). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.  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
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationXu, G. J., Zhao, Y. H., Shao, K. Z., Lan, Y. Q., Wang, X. L., Su, Z. M. & Yan, L. K. (2009). CrystEngComm, 11, 1842–1847.  Web of Science CSD CrossRef CAS Google Scholar

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