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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

4,4,5,5-Tetra­methyl-2-(4-pyridyl)­imidazolidin-1-oxyl-3-oxide tri­chloro­acetic acid solvate

aDepartment of Chemistry, Key Laboratory of Medicinal Chemistry for Natural Resources, Ministry of Education, Yunnan University, Kunming 650091, People's Republic of China, and bOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 210096, People's Republic of China
*Correspondence e-mail: chmsunbw@seu.edu.cn

(Received 9 May 2008; accepted 28 May 2008; online 7 June 2008)

In the title compound, C12H16N3O2·C2HCl3O2, the imidazolidine ring adopts a twist conformation. The crystal structure is stabilized by inter­molecular O—H⋯N hydrogen bonds.

Related literature

For related literature, see: Zhang et al. (2006[Zhang, C.-X., Sun, D.-L. & Wang, X.-C. (2006). Acta Cryst. E62, o5666-o5667.]); Ullman et al. (1972[Ullman, E. F., Osiecki, J. H., Boocock, D. G. B. & Darcy, R. (1972). J. Am. Chem. Soc. , 94, 7049-7059.]); Oshio et al. (2002[Oshio, H., Yamamoto, M. & Ito, T. (2002). Inorg. Chem. 41, 5817-5820.]); Vostrikova et al. (2000[Vostrikova, K. E., Luneau, D., Wernsdorfer, W., Rey, P. & Verdaguer, M. (2000). J. Am. Chem. Soc. 122, 718-719.]).

[Scheme 1]

Experimental

Crystal data
  • C12H16N3O2·C2HCl3O2

  • Mr = 397.66

  • Monoclinic, P 21 /c

  • a = 10.003 (2) Å

  • b = 21.036 (4) Å

  • c = 9.2796 (19) Å

  • β = 115.33 (3)°

  • V = 1764.9 (7) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.54 mm−1

  • T = 293 (2) K

  • 0.20 × 0.20 × 0.20 mm

Data collection
  • Bruker SMART 1K CCD area-detector diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2005[Rigaku. (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.895, Tmax = 0.898

  • 14888 measured reflections

  • 3100 independent reflections

  • 2041 reflections with I > 2σ(I)

  • Rint = 0.098

Refinement
  • R[F2 > 2σ(F2)] = 0.064

  • wR(F2) = 0.132

  • S = 1.06

  • 3100 reflections

  • 217 parameters

  • H-atom parameters constrained

  • Δρmax = 0.36 e Å−3

  • Δρmin = −0.26 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O4—H4B⋯N1i 0.82 1.75 2.567 (7) 173
Symmetry code: (i) -x+2, -y, -z.

Data collection: CrystalClear (Rigaku, 2005[Rigaku. (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; 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: SHELXTL.

Supporting information


Comment top

Transition metal compounds containing nitroxide radical ligands are of great interest, as these compounds play an important role in molecule-based magnetic materials (Oshio et al., 2002; Vostrikova et al., 2000). In order to investigate the crystal structure of such ligands, the title compound has been synthesized and its crystal structure is reported here.

In the title compound (Fig. 1), the imidazole ring adopts a twist conformation, with atoms C7 and C10 displaced by 0.218 (4) and 0.240 (4) Å respectively on opposite sides of the plane through atoms N2, N3, C6. The dihedral angle between the pyridine and the mean plane of the imidazole ring is 20.31 (27)°. This angle is smaller than that of 25.66 (15)° observed in the unsolvated compound (Zhang et al., 2006). In the crystal structure, an intermolecular hydrogen bonding interaction involving the hydroxyl group of the trichloroacetic acid and the N atom of the pyridine ring is observed (Table 1).

Related literature top

For related literature, see: Zhang et al. (2006); Ullman et al. (1972); Oshio et al. (2002); Vostrikova et al. (2000).

Experimental top

4,4,5,5-Tetramethyl-2-(4-pyridyl)imidazolin-1-oxyl-3-oxide was prepared according to the published method (Ullman et al., 1972). All chemicals used (reagent grade) were commercially available. 2-(4-Pyridyl)-4,4,5,5-teramethylimidazolin-1-oxyl-3-oxide (0.024 g, 0.1 mmol) was dissolved in ethanol (10 ml). Trichloroacetic acid (0.016 g, 0.1 mmol) was added slowly with stirring. The resulted solution was continuously stirred for about 30 min at room temperature and then filtered. The filtrate was slowly evaporated at room temperature over several days, to give colourless crystals suitable for X-ray analysis.

Refinement top

All H atoms were placed at calculated positions and allowed to ride on their parent atoms, with C—H = 0.93–0.96 Å, O—H = 0.82 Å, and with Uiso(H) = 1.5 Ueq(C, O) or 1.2 Ueq(C) for aromatic H atoms.

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); 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: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. All hydrogen atoms are omitted except for H4B. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. Packing diagram of the title compound viewed along the b axis. Hydrogen bonds are shown as dashed lines. All hydrogen atoms are omitted except for H4B.
4,4,5,5-Tetramethyl-2-(4-pyridyl)imidazolidin-1-oxyl-3-oxide trichloroacetic acid solvate top
Crystal data top
C12H16N3O2·C2HCl3O2F(000) = 820
Mr = 397.66Dx = 1.497 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 12720 reflections
a = 10.003 (2) Åθ = 1.0–27.6°
b = 21.036 (4) ŵ = 0.54 mm1
c = 9.2796 (19) ÅT = 293 K
β = 115.33 (3)°Prism, colourless
V = 1764.9 (7) Å30.20 × 0.20 × 0.20 mm
Z = 4
Data collection top
Bruker SMART 1K CCD area-detector
diffractometer
3100 independent reflections
Radiation source: fine-focus sealed tube2041 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.098
Detector resolution: 8.192 pixels mm-1θmax = 25.0°, θmin = 2.5°
thin–slice ω scansh = 1111
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
k = 2525
Tmin = 0.895, Tmax = 0.898l = 1111
14888 measured reflections
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)] = 0.064Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.132H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0424P)2 + 1.1663P]
where P = (Fo2 + 2Fc2)/3
3100 reflections(Δ/σ)max < 0.001
217 parametersΔρmax = 0.36 e Å3
0 restraintsΔρmin = 0.26 e Å3
Crystal data top
C12H16N3O2·C2HCl3O2V = 1764.9 (7) Å3
Mr = 397.66Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.003 (2) ŵ = 0.54 mm1
b = 21.036 (4) ÅT = 293 K
c = 9.2796 (19) Å0.20 × 0.20 × 0.20 mm
β = 115.33 (3)°
Data collection top
Bruker SMART 1K CCD area-detector
diffractometer
3100 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
2041 reflections with I > 2σ(I)
Tmin = 0.895, Tmax = 0.898Rint = 0.098
14888 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0640 restraints
wR(F2) = 0.132H-atom parameters constrained
S = 1.06Δρmax = 0.36 e Å3
3100 reflectionsΔρmin = 0.26 e Å3
217 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
Cl10.23783 (13)0.11481 (6)0.16145 (14)0.0544 (4)
Cl20.44021 (13)0.19710 (5)0.40583 (14)0.0544 (4)
Cl30.50692 (15)0.06513 (6)0.41125 (15)0.0620 (4)
N31.0715 (4)0.17317 (15)0.4059 (4)0.0378 (8)
O10.9245 (3)0.03239 (13)0.2203 (3)0.0485 (8)
N20.9604 (3)0.08379 (15)0.2999 (4)0.0330 (8)
N11.3320 (4)0.10702 (18)0.0574 (4)0.0431 (9)
C140.5057 (4)0.1426 (2)0.1725 (5)0.0396 (10)
C61.0677 (4)0.12466 (18)0.3092 (4)0.0326 (9)
O40.5301 (4)0.09179 (15)0.1183 (4)0.0594 (9)
H4B0.57060.09950.05980.089*
C31.1616 (4)0.11841 (18)0.2243 (4)0.0318 (9)
O21.1539 (4)0.22208 (15)0.4388 (4)0.0679 (10)
O30.5285 (4)0.19655 (16)0.1466 (4)0.0700 (10)
C70.8677 (4)0.11090 (19)0.3775 (5)0.0365 (10)
C100.9750 (4)0.15972 (19)0.4916 (5)0.0363 (10)
C51.3255 (5)0.1617 (2)0.1249 (5)0.0456 (11)
H5A1.37790.19630.11340.055*
C130.4289 (4)0.13093 (18)0.2862 (5)0.0369 (10)
C41.2440 (4)0.16910 (19)0.2113 (5)0.0396 (10)
H4A1.24430.20770.26040.048*
C21.1702 (5)0.0613 (2)0.1541 (5)0.0513 (12)
H2A1.11780.02600.16220.062*
C120.9050 (5)0.2207 (2)0.5118 (6)0.0630 (14)
H12A0.83990.23700.40900.094*
H12B0.84980.21250.57270.094*
H12C0.98090.25140.56670.094*
C90.7334 (5)0.1403 (2)0.2419 (5)0.0587 (13)
H9A0.76510.17390.19360.088*
H9B0.68280.10840.16360.088*
H9C0.66770.15730.28320.088*
C111.0795 (5)0.1329 (2)0.6540 (5)0.0599 (13)
H11A1.12230.09400.63930.090*
H11B1.15660.16310.70880.090*
H11C1.02520.12470.71600.090*
C11.2570 (5)0.0571 (2)0.0721 (5)0.0537 (13)
H1B1.26330.01860.02620.064*
C80.8203 (5)0.0578 (2)0.4560 (6)0.0582 (13)
H8A0.90590.03990.54130.087*
H8B0.75460.07440.49760.087*
H8C0.77050.02540.37860.087*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0439 (7)0.0609 (8)0.0638 (8)0.0087 (6)0.0282 (6)0.0041 (6)
Cl20.0639 (8)0.0492 (7)0.0615 (8)0.0039 (6)0.0378 (6)0.0122 (6)
Cl30.0845 (9)0.0510 (7)0.0616 (8)0.0196 (7)0.0417 (7)0.0269 (6)
N30.043 (2)0.0336 (19)0.043 (2)0.0057 (17)0.0234 (17)0.0060 (16)
O10.0541 (19)0.0439 (18)0.059 (2)0.0196 (15)0.0354 (16)0.0186 (15)
N20.0348 (19)0.0324 (19)0.034 (2)0.0051 (16)0.0171 (16)0.0023 (15)
N10.042 (2)0.053 (2)0.041 (2)0.0010 (19)0.0237 (18)0.0032 (18)
C140.032 (2)0.052 (3)0.037 (3)0.001 (2)0.016 (2)0.007 (2)
C60.034 (2)0.034 (2)0.031 (2)0.004 (2)0.0153 (19)0.0018 (18)
O40.071 (2)0.069 (2)0.061 (2)0.0061 (19)0.0502 (19)0.0005 (17)
C30.031 (2)0.036 (2)0.028 (2)0.0002 (19)0.0128 (18)0.0016 (17)
O20.082 (2)0.053 (2)0.093 (3)0.0336 (19)0.061 (2)0.0324 (18)
O30.100 (3)0.055 (2)0.077 (3)0.011 (2)0.058 (2)0.0171 (18)
C70.030 (2)0.044 (3)0.042 (3)0.001 (2)0.022 (2)0.000 (2)
C100.036 (2)0.043 (3)0.035 (2)0.001 (2)0.021 (2)0.0006 (19)
C50.037 (2)0.046 (3)0.061 (3)0.003 (2)0.027 (2)0.012 (2)
C130.041 (2)0.033 (2)0.043 (3)0.0003 (19)0.024 (2)0.0059 (19)
C40.043 (3)0.030 (2)0.052 (3)0.000 (2)0.026 (2)0.0032 (19)
C20.060 (3)0.049 (3)0.062 (3)0.019 (2)0.043 (3)0.016 (2)
C120.061 (3)0.057 (3)0.084 (4)0.000 (3)0.044 (3)0.019 (3)
C90.036 (3)0.079 (4)0.051 (3)0.012 (3)0.010 (2)0.005 (3)
C110.055 (3)0.075 (4)0.045 (3)0.007 (3)0.017 (2)0.002 (2)
C10.065 (3)0.055 (3)0.058 (3)0.017 (3)0.041 (3)0.023 (2)
C80.064 (3)0.065 (3)0.064 (3)0.012 (3)0.045 (3)0.007 (3)
Geometric parameters (Å, º) top
Cl1—C131.793 (4)C10—C121.512 (6)
Cl2—C131.754 (4)C10—C111.528 (6)
Cl3—C131.760 (4)C5—C41.375 (5)
N3—O21.271 (4)C5—H5A0.9300
N3—C61.349 (5)C4—H4A0.9300
N3—C101.517 (5)C2—C11.381 (5)
O1—N21.272 (4)C2—H2A0.9300
N2—C61.349 (5)C12—H12A0.9600
N2—C71.508 (5)C12—H12B0.9600
N1—C51.324 (5)C12—H12C0.9600
N1—C11.331 (5)C9—H9A0.9600
C14—O31.202 (5)C9—H9B0.9600
C14—O41.249 (5)C9—H9C0.9600
C14—C131.568 (5)C11—H11A0.9600
C6—C31.467 (5)C11—H11B0.9600
O4—H4B0.8200C11—H11C0.9600
C3—C41.385 (5)C1—H1B0.9300
C3—C21.387 (5)C8—H8A0.9600
C7—C81.516 (5)C8—H8B0.9600
C7—C91.525 (6)C8—H8C0.9600
C7—C101.535 (6)
O2—N3—C6127.0 (3)Cl2—C13—Cl1108.7 (2)
O2—N3—C10121.2 (3)Cl3—C13—Cl1109.1 (2)
C6—N3—C10111.4 (3)C5—C4—C3119.1 (4)
O1—N2—C6126.8 (3)C5—C4—H4A120.4
O1—N2—C7121.3 (3)C3—C4—H4A120.4
C6—N2—C7111.3 (3)C1—C2—C3119.6 (4)
C5—N1—C1119.5 (3)C1—C2—H2A120.2
O3—C14—O4129.9 (4)C3—C2—H2A120.2
O3—C14—C13118.1 (4)C10—C12—H12A109.5
O4—C14—C13111.9 (4)C10—C12—H12B109.5
N3—C6—N2108.6 (3)H12A—C12—H12B109.5
N3—C6—C3125.7 (3)C10—C12—H12C109.5
N2—C6—C3125.7 (3)H12A—C12—H12C109.5
C14—O4—H4B109.5H12B—C12—H12C109.5
C4—C3—C2117.9 (4)C7—C9—H9A109.5
C4—C3—C6121.3 (3)C7—C9—H9B109.5
C2—C3—C6120.8 (3)H9A—C9—H9B109.5
N2—C7—C8109.4 (3)C7—C9—H9C109.5
N2—C7—C9105.3 (3)H9A—C9—H9C109.5
C8—C7—C9110.4 (4)H9B—C9—H9C109.5
N2—C7—C10101.0 (3)C10—C11—H11A109.5
C8—C7—C10115.6 (3)C10—C11—H11B109.5
C9—C7—C10114.0 (3)H11A—C11—H11B109.5
C12—C10—N3109.8 (3)C10—C11—H11C109.5
C12—C10—C11110.4 (4)H11A—C11—H11C109.5
N3—C10—C11105.4 (3)H11B—C11—H11C109.5
C12—C10—C7115.4 (3)N1—C1—C2121.4 (4)
N3—C10—C7100.2 (3)N1—C1—H1B119.3
C11—C10—C7114.5 (3)C2—C1—H1B119.3
N1—C5—C4122.4 (4)C7—C8—H8A109.5
N1—C5—H5A118.8C7—C8—H8B109.5
C4—C5—H5A118.8H8A—C8—H8B109.5
C14—C13—Cl2112.6 (3)C7—C8—H8C109.5
C14—C13—Cl3111.1 (3)H8A—C8—H8C109.5
Cl2—C13—Cl3108.5 (2)H8B—C8—H8C109.5
C14—C13—Cl1106.8 (3)
O2—N3—C6—N2177.0 (4)N2—C7—C10—C12143.3 (3)
C10—N3—C6—N29.8 (4)C8—C7—C10—C1298.8 (4)
O2—N3—C6—C31.2 (7)C9—C7—C10—C1230.8 (5)
C10—N3—C6—C3172.0 (3)N2—C7—C10—N325.4 (3)
O1—N2—C6—N3179.8 (3)C8—C7—C10—N3143.4 (3)
C7—N2—C6—N39.0 (4)C9—C7—C10—N387.0 (4)
O1—N2—C6—C32.0 (6)N2—C7—C10—C1186.8 (4)
C7—N2—C6—C3169.3 (4)C8—C7—C10—C1131.1 (5)
N3—C6—C3—C413.2 (6)C9—C7—C10—C11160.7 (4)
N2—C6—C3—C4164.8 (4)C1—N1—C5—C40.3 (6)
N3—C6—C3—C2166.9 (4)O3—C14—C13—Cl218.8 (5)
N2—C6—C3—C215.1 (6)O4—C14—C13—Cl2163.2 (3)
O1—N2—C7—C843.0 (5)O3—C14—C13—Cl3140.6 (4)
C6—N2—C7—C8145.2 (3)O4—C14—C13—Cl341.3 (4)
O1—N2—C7—C975.8 (4)O3—C14—C13—Cl1100.5 (4)
C6—N2—C7—C996.0 (4)O4—C14—C13—Cl177.5 (4)
O1—N2—C7—C10165.3 (3)N1—C5—C4—C32.2 (6)
C6—N2—C7—C1022.9 (4)C2—C3—C4—C52.6 (6)
O2—N3—C10—C1241.2 (5)C6—C3—C4—C5177.3 (4)
C6—N3—C10—C12145.1 (4)C4—C3—C2—C11.2 (6)
O2—N3—C10—C1177.7 (4)C6—C3—C2—C1178.7 (4)
C6—N3—C10—C1195.9 (4)C5—N1—C1—C21.1 (7)
O2—N3—C10—C7163.1 (4)C3—C2—C1—N10.7 (7)
C6—N3—C10—C723.2 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4—H4B···N1i0.821.752.567 (7)173
Symmetry code: (i) x+2, y, z.

Experimental details

Crystal data
Chemical formulaC12H16N3O2·C2HCl3O2
Mr397.66
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)10.003 (2), 21.036 (4), 9.2796 (19)
β (°) 115.33 (3)
V3)1764.9 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.54
Crystal size (mm)0.20 × 0.20 × 0.20
Data collection
DiffractometerBruker SMART 1K CCD area-detector
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2005)
Tmin, Tmax0.895, 0.898
No. of measured, independent and
observed [I > 2σ(I)] reflections
14888, 3100, 2041
Rint0.098
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.064, 0.132, 1.06
No. of reflections3100
No. of parameters217
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.36, 0.26

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O4—H4B···N1i0.821.752.567 (7)173
Symmetry code: (i) x+2, y, z.
 

References

First citationOshio, H., Yamamoto, M. & Ito, T. (2002). Inorg. Chem. 41, 5817–5820.  Web of Science CSD CrossRef PubMed CAS Google Scholar
First citationRigaku. (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationUllman, E. F., Osiecki, J. H., Boocock, D. G. B. & Darcy, R. (1972). J. Am. Chem. Soc. , 94, 7049–7059.  CrossRef CAS Web of Science Google Scholar
First citationVostrikova, K. E., Luneau, D., Wernsdorfer, W., Rey, P. & Verdaguer, M. (2000). J. Am. Chem. Soc. 122, 718–719.  Web of Science CSD CrossRef CAS Google Scholar
First citationZhang, C.-X., Sun, D.-L. & Wang, X.-C. (2006). Acta Cryst. E62, o5666–o5667.  Web of Science CSD CrossRef 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