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

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ISSN: 2414-3146

Tris(ethane-1,2-di­amine-κ2N,N′)zinc(II) tetra­chlorido­zincate(II)

aDepartment of Physics, Presidency College (Autonomous), Chennai 600 005, India, and bDepartment of Chemistry, Pondicherry University, Pondicherry 605 014, India
*Correspondence e-mail: aspandian59@gmail.com

Edited by M. Bolte, Goethe-Universität Frankfurt, Germany (Received 5 May 2020; accepted 6 May 2020; online 12 May 2020)

The title complex, [Zn(C2H8N2)3][ZnCl4], exists as discrete ions. The [Zn(C2H8N2)3]2+ cation exhibits a distorted octa­hedral shape. In the [ZnCl4]2− anion, the ZnII atom is in an almost regular tetra­hedral environment. The crystal packing is consolidated by N—H⋯Cl and C—H⋯Cl hydrogen bonds.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

Ethyl­enedi­amine (en) is a common chelating ligand that is widely used in transition-metal complexes. It cannot only chelate metal cations by two nitro­gen atoms, but also offers hydrogen atoms to form N—H⋯X hydrogen bonds. Metal complexes containing an ethyl­enedi­amine (–NCH2CH2N) backbone have attracted significant inter­est as potential anti­cancer agents because of their rich redox chemistry and relative ease of manipulation (Mihajlović et al., 2012[Mihajlović, L. E., Savić, A., Poljarević, J., Vučković, I., Mojić, M., Bulatović, M., Maksimović-Ivanić, D., Mijatović, S., Kaluđerović, G. N., Stošić-Grujičić, S., Miljković, D., Grgurić-Šipka, S. & Sabo, T. J. (2012). J. Inorg. Biochem. 109, 40-48.]; Beaumont et al., 1976[Beaumont, K. P., McAuliffe, C. A. & Cleare, M. J. (1976). Chem. Biol. Interact. 14, 179-193.]). Metal-containing compounds offer many advantages over conventional carbon-based compounds, their ability to coordinate ligands in a three-dimensional configuration allowing the functionalization of groups that can be tailored to defined mol­ecular targets (Fricker, 2007[Fricker, S. P. (2007). Dalton Trans. pp. 4903-4917.]; Meggers, 2009[Meggers, E. (2009). Chem. Commun. pp. 1001-1010.]).

Metals such as zinc act as a key structural component in many proteins and enzymes, including transcription factors, cellular signalling proteins and DNA repair enzymes (Prasad, 1995[Prasad, A. S. (1995). Nutrition, 11, 93-99.]; Prasad & Kucuk, 2002[Prasad, A. S. & Kucuk, O. (2002). Cancer Metastasis Rev. 21, 291-295.]). Zinc deficiency during pregnancy may produce serious defects and foetal loss (Hernick & Fierke, 2005[Hernick, M. & Fierke, C. A. (2005). Arch. Biochem. Biophys. 433, 71-84.]). Zinc also possesses anti­viral, anti­bacterial and wound-healing properties with zinc complexes also being used in the treatment of gastrointestinal disorders, acne and infertility (Cunnane, 1988[Cunnane, S. C. (1988). Zinc: Clinical and Biochemical Significance. Boca Raton, Florida: CRC Press.]). Against this background, the X-ray structural characterization of the title compound has been carried out in order to determine the mol­ecular conformation, binding modes and hydrogen-bonding inter­actions.

Fig. 1[link] shows the mol­ecular entities of the title complex, [Zn(C2H8N2)3][ZnCl4], which comprises an ZnCl42− anion and a [Zn(en)3]2+complex cation. The ZnII atom of the tetra­chlorido­zincate(II) anion is in an almost regular Cl4 tetra­hedral environment, with Zn—Cl bond lengths in the range 2.255 (1)-2.272 (9) Å. The zinc cation displays a distorted octa­hedral coordination geometry defined by six N atoms from three ethyl­enedi­amine ligands, with Zn—N distances in the range of 2.173 (3)–2.219 (3) Å. The N—Zn—N angles of the en ligands are about 80°. They are noticeably smaller than the ideal octa­hedral angle of 90°. The five-membered chelate rings are non-planar, with N—C—C—N torsion angles of −57.5 (4), −55.4 (4) and −55.9 (5)°. All of the three en ligands assume a synclinal conformation about the C—C bond.

[Figure 1]
Figure 1
View of the mol­ecular structure of the title complex, showing the atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

In the crystal structure, adjacent ions are connected via inter­molecular hydrogen bonds. The N—H⋯Cl hydrogen-bonding inter­actions between the N atoms of the ethyl­enedi­amine ligands and Cl atoms of the tetra­chlorido­zincate anion connect the mol­ecules, together with the weak C—H⋯Cl intra­molecular inter­actions, generating a three-dimensional network (Fig. 2[link], Table 1[link]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1D⋯Cl1i 0.89 2.88 3.617 (3) 142
N1—H1D⋯Cl3i 0.89 2.95 3.677 (3) 140
N2—H2C⋯Cl1ii 0.89 2.56 3.426 (3) 165
N2—H2D⋯Cl3iii 0.89 2.51 3.395 (3) 171
N3—H3C⋯Cl1ii 0.89 2.67 3.500 (3) 155
N3—H3D⋯Cl1i 0.89 2.99 3.670 (3) 135
N3—H3D⋯Cl2i 0.89 2.85 3.600 (3) 143
N4—H4C⋯Cl4iv 0.89 2.63 3.437 (3) 152
N4—H4D⋯Cl2iii 0.89 2.76 3.581 (3) 153
N5—H5C⋯Cl4iv 0.89 2.58 3.431 (3) 160
N5—H5D⋯Cl3i 0.89 2.50 3.360 (3) 162
N6—H6C⋯Cl2v 0.89 2.91 3.646 (3) 141
N6—H6D⋯Cl3iii 0.89 2.91 3.652 (3) 142
N6—H6D⋯Cl4iii 0.89 2.90 3.609 (3) 138
C3—H3B⋯Cl3 0.97 2.82 3.662 (3) 146
Symmetry codes: (i) x-1, y, z; (ii) -x+2, -y+1, -z+2; (iii) [x-{\script{1\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]; (iv) [-x+{\script{3\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (v) [x-{\script{3\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}].
[Figure 2]
Figure 2
The crystal packing of title complex, viewed approximately down the a axis, with hydrogen bonds (Table 1[link]) shown as dashed lines.

Synthesis and crystallization

Zinc chloride (1.36 g, 2 mol) was dissolved in 25 ml of EtOH/H2O (1:4 v/v) mixture. To this solution, ethyl­enedi­amine (1.0 ml, 3 mol) in 25 ml of an HCl/EtOH (2:3 v/v) mixture was added dropwise. The mixture was stirred and heated to 338 K for 2 h and allowed to stand at room temperature until colourless crystals separated (3–4 weeks). Crystals suitable for single-crystal XRD were collected after recrystallization using acidified water.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link].

Table 2
Experimental details

Crystal data
Chemical formula [Zn(C2H8N2)3][ZnCl4]
Mr 452.85
Crystal system, space group Monoclinic, P21/n
Temperature (K) 293
a, b, c (Å) 8.6916 (4), 14.6035 (9), 14.0382 (7)
β (°) 91.201 (4)
V3) 1781.45 (16)
Z 4
Radiation type Mo Kα
μ (mm−1) 3.29
Crystal size (mm) 0.20 × 0.12 × 0.10
 
Data collection
Diffractometer Oxford Diffraction Xcalibur diffractometer with EOS detector
Absorption correction Multi-scan (CrysAlis PRO; Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis CCD, CrysAlis RED and CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.])
Tmin, Tmax 0.629, 0.720
No. of measured, independent and observed [I > 2σ(I)] reflections 10159, 3119, 2582
Rint 0.027
(sin θ/λ)max−1) 0.595
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.075, 1.04
No. of reflections 3119
No. of parameters 163
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.65, −0.35
Computer programs: CrysAlis CCD and CrysAlis RED (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis CCD, CrysAlis RED and CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014/7 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]) and PLATON (Spek, 2020[Spek, A. L. (2020). Acta Cryst. E76, 1-11.]).

Structural data


Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2009); cell refinement: CrysAlis RED (Oxford Diffraction, 2009); data reduction: CrysAlis RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2020); software used to prepare material for publication: SHELXL2014/7 (Sheldrick, 2015) and PLATON (Spek, 2020).

Tris(ethane-1,2-diamine-κ2N,N')zinc(II) tetrachloridozincate(II) top
Crystal data top
[Zn(C2H8N2)3][ZnCl4]F(000) = 920
Mr = 452.85Dx = 1.688 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 8.6916 (4) ÅCell parameters from 2582 reflections
b = 14.6035 (9) Åθ = 3.9–25.0°
c = 14.0382 (7) ŵ = 3.29 mm1
β = 91.201 (4)°T = 293 K
V = 1781.45 (16) Å3Block, colourless
Z = 40.20 × 0.12 × 0.10 mm
Data collection top
Oxford Diffraction Xcalibur
diffractometer with EOS detector
2582 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.027
ω and φ scansθmax = 25.0°, θmin = 3.9°
Absorption correction: multi-scan
(CrysAlis Pro; Oxford Diffraction, 2009)
h = 109
Tmin = 0.629, Tmax = 0.720k = 1617
10159 measured reflectionsl = 1616
3119 independent reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.031H-atom parameters constrained
wR(F2) = 0.075 w = 1/[σ2(Fo2) + (0.0348P)2 + 0.9424P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
3119 reflectionsΔρmax = 0.65 e Å3
163 parametersΔρmin = 0.35 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.

Refinement. All H atoms were fixed geometrically and allow to ride on their parent C and N atoms, with C—H distances of 0.97 Å and N—H distances of 0.90 Å, and with Uiso(H)= 1.2 Ueq(parent atom).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.2695 (6)0.5672 (3)1.1390 (3)0.0762 (13)
H1A0.19360.52631.16540.091*
H1B0.34210.53071.10370.091*
C20.3510 (5)0.6156 (3)1.2166 (3)0.0711 (12)
H2A0.27730.64731.25560.085*
H2B0.40590.57171.25650.085*
C30.6033 (4)0.7154 (3)0.9023 (2)0.0504 (9)
H3A0.55100.75280.85460.061*
H3B0.67850.67770.87060.061*
C40.6819 (4)0.7751 (3)0.9736 (3)0.0515 (9)
H4A0.74290.73771.01730.062*
H4B0.75080.81660.94160.062*
C50.1177 (4)0.8682 (3)0.9718 (3)0.0620 (11)
H5A0.02970.83340.99300.074*
H5B0.08240.91080.92310.074*
C60.1881 (4)0.9199 (3)1.0543 (3)0.0588 (10)
H6A0.27180.95781.03230.071*
H6B0.11150.95961.08200.071*
N10.1919 (4)0.6337 (2)1.0733 (2)0.0579 (8)
H1C0.10790.65651.09970.069*
H1D0.16490.60661.01870.069*
N20.4594 (4)0.68128 (19)1.17780 (17)0.0474 (7)
H2C0.54720.65311.16460.057*
H2D0.47970.72471.22070.057*
N30.4909 (3)0.65660 (18)0.95024 (18)0.0420 (6)
H3C0.53930.61200.98200.050*
H3D0.42690.63130.90750.050*
N40.5683 (3)0.82833 (18)1.02757 (18)0.0399 (6)
H4C0.54240.87880.99550.048*
H4D0.60880.84491.08370.048*
N50.2326 (3)0.80599 (18)0.93231 (19)0.0427 (7)
H5C0.29590.83700.89510.051*
H5D0.18610.76300.89720.051*
N60.2461 (3)0.8549 (2)1.1263 (2)0.0489 (7)
H6C0.16870.83271.15980.059*
H6D0.31220.88261.16610.059*
Zn10.36240 (4)0.74282 (2)1.04903 (2)0.03245 (12)
Zn21.16044 (4)0.54507 (3)0.77627 (3)0.04177 (13)
Cl11.24823 (14)0.45660 (8)0.89729 (7)0.0752 (3)
Cl21.35279 (12)0.62417 (13)0.70905 (7)0.1022 (5)
Cl30.99364 (9)0.64689 (6)0.83974 (6)0.0446 (2)
Cl41.02570 (12)0.46530 (7)0.66406 (7)0.0646 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.113 (4)0.051 (3)0.066 (3)0.026 (3)0.019 (3)0.013 (2)
C20.101 (4)0.064 (3)0.048 (2)0.003 (2)0.010 (2)0.015 (2)
C30.040 (2)0.064 (2)0.048 (2)0.0067 (18)0.0081 (16)0.0030 (18)
C40.0315 (18)0.062 (2)0.061 (2)0.0012 (17)0.0004 (16)0.0065 (19)
C50.038 (2)0.065 (3)0.081 (3)0.0135 (19)0.0173 (19)0.003 (2)
C60.047 (2)0.047 (2)0.082 (3)0.0155 (18)0.002 (2)0.007 (2)
N10.057 (2)0.058 (2)0.0594 (19)0.0205 (16)0.0080 (15)0.0083 (16)
N20.068 (2)0.0403 (17)0.0335 (14)0.0060 (15)0.0022 (13)0.0020 (12)
N30.0433 (16)0.0411 (16)0.0414 (14)0.0048 (13)0.0033 (12)0.0036 (12)
N40.0363 (15)0.0412 (16)0.0419 (14)0.0021 (12)0.0094 (11)0.0002 (13)
N50.0381 (15)0.0406 (16)0.0489 (16)0.0051 (13)0.0142 (12)0.0005 (13)
N60.0381 (16)0.0548 (19)0.0539 (17)0.0043 (14)0.0014 (13)0.0109 (15)
Zn10.0331 (2)0.0308 (2)0.03334 (19)0.00077 (15)0.00142 (14)0.00084 (15)
Zn20.0372 (2)0.0524 (3)0.0353 (2)0.01035 (18)0.00777 (16)0.00588 (18)
Cl10.0995 (8)0.0657 (7)0.0594 (6)0.0405 (6)0.0250 (6)0.0033 (5)
Cl20.0491 (7)0.2003 (17)0.0572 (6)0.0341 (8)0.0002 (5)0.0172 (8)
Cl30.0429 (5)0.0360 (5)0.0546 (5)0.0064 (4)0.0047 (4)0.0084 (4)
Cl40.0747 (7)0.0603 (6)0.0580 (6)0.0128 (5)0.0195 (5)0.0288 (5)
Geometric parameters (Å, º) top
C1—C21.467 (5)N1—H1C0.8900
C1—N11.490 (5)N1—H1D0.8900
C1—H1A0.9700N2—Zn12.173 (3)
C1—H1B0.9700N2—H2C0.8900
C2—N21.458 (5)N2—H2D0.8900
C2—H2A0.9700N3—Zn12.196 (2)
C2—H2B0.9700N3—H3C0.8900
C3—N31.473 (4)N3—H3D0.8900
C3—C41.483 (5)N4—Zn12.208 (3)
C3—H3A0.9700N4—H4C0.8900
C3—H3B0.9700N4—H4D0.8900
C4—N41.478 (4)N5—Zn12.175 (2)
C4—H4A0.9700N5—H5C0.8900
C4—H4B0.9700N5—H5D0.8900
C5—N51.468 (4)N6—Zn12.219 (3)
C5—C61.502 (5)N6—H6C0.8900
C5—H5A0.9700N6—H6D0.8900
C5—H5B0.9700Zn2—Cl12.2546 (10)
C6—N61.468 (4)Zn2—Cl22.2552 (12)
C6—H6A0.9700Zn2—Cl42.2654 (9)
C6—H6B0.9700Zn2—Cl32.2718 (9)
N1—Zn12.208 (3)
C2—C1—N1110.6 (3)H2C—N2—H2D108.2
C2—C1—H1A109.5C3—N3—Zn1107.77 (19)
N1—C1—H1A109.5C3—N3—H3C110.2
C2—C1—H1B109.5Zn1—N3—H3C110.2
N1—C1—H1B109.5C3—N3—H3D110.2
H1A—C1—H1B108.1Zn1—N3—H3D110.2
N2—C2—C1110.2 (3)H3C—N3—H3D108.5
N2—C2—H2A109.6C4—N4—Zn1108.9 (2)
C1—C2—H2A109.6C4—N4—H4C109.9
N2—C2—H2B109.6Zn1—N4—H4C109.9
C1—C2—H2B109.6C4—N4—H4D109.9
H2A—C2—H2B108.1Zn1—N4—H4D109.9
N3—C3—C4109.5 (3)H4C—N4—H4D108.3
N3—C3—H3A109.8C5—N5—Zn1108.9 (2)
C4—C3—H3A109.8C5—N5—H5C109.9
N3—C3—H3B109.8Zn1—N5—H5C109.9
C4—C3—H3B109.8C5—N5—H5D109.9
H3A—C3—H3B108.2Zn1—N5—H5D109.9
N4—C4—C3110.6 (3)H5C—N5—H5D108.3
N4—C4—H4A109.5C6—N6—Zn1107.1 (2)
C3—C4—H4A109.5C6—N6—H6C110.3
N4—C4—H4B109.5Zn1—N6—H6C110.3
C3—C4—H4B109.5C6—N6—H6D110.3
H4A—C4—H4B108.1Zn1—N6—H6D110.3
N5—C5—C6109.4 (3)H6C—N6—H6D108.6
N5—C5—H5A109.8N2—Zn1—N5171.16 (11)
C6—C5—H5A109.8N2—Zn1—N395.43 (10)
N5—C5—H5B109.8N5—Zn1—N391.72 (10)
C6—C5—H5B109.8N2—Zn1—N179.79 (12)
H5A—C5—H5B108.2N5—Zn1—N194.79 (11)
N6—C6—C5109.5 (3)N3—Zn1—N192.04 (11)
N6—C6—H6A109.8N2—Zn1—N492.64 (11)
C5—C6—H6A109.8N5—Zn1—N493.80 (10)
N6—C6—H6B109.8N3—Zn1—N479.26 (10)
C5—C6—H6B109.8N1—Zn1—N4167.95 (11)
H6A—C6—H6B108.2N2—Zn1—N694.08 (11)
C1—N1—Zn1105.6 (2)N5—Zn1—N679.69 (10)
C1—N1—H1C110.6N3—Zn1—N6167.09 (10)
Zn1—N1—H1C110.6N1—Zn1—N698.21 (11)
C1—N1—H1D110.6N4—Zn1—N691.62 (10)
Zn1—N1—H1D110.6Cl1—Zn2—Cl2111.51 (5)
H1C—N1—H1D108.8Cl1—Zn2—Cl4113.03 (4)
C2—N2—Zn1109.9 (2)Cl2—Zn2—Cl4110.45 (4)
C2—N2—H2C109.7Cl1—Zn2—Cl3106.75 (4)
Zn1—N2—H2C109.7Cl2—Zn2—Cl3108.28 (5)
C2—N2—H2D109.7Cl4—Zn2—Cl3106.52 (4)
Zn1—N2—H2D109.7
N1—C1—C2—N255.9 (5)C4—C3—N3—Zn145.2 (3)
N3—C3—C4—N455.4 (4)C3—C4—N4—Zn135.9 (3)
N5—C5—C6—N657.5 (4)C6—C5—N5—Zn141.1 (4)
C2—C1—N1—Zn144.6 (4)C5—C6—N6—Zn142.6 (3)
C1—C2—N2—Zn136.6 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1D···Cl1i0.892.883.617 (3)142
N1—H1D···Cl3i0.892.953.677 (3)140
N2—H2C···Cl1ii0.892.563.426 (3)165
N2—H2D···Cl3iii0.892.513.395 (3)171
N3—H3C···Cl1ii0.892.673.500 (3)155
N3—H3D···Cl1i0.892.993.670 (3)135
N3—H3D···Cl2i0.892.853.600 (3)143
N4—H4C···Cl4iv0.892.633.437 (3)152
N4—H4D···Cl2iii0.892.763.581 (3)153
N5—H5C···Cl4iv0.892.583.431 (3)160
N5—H5D···Cl3i0.892.503.360 (3)162
N6—H6C···Cl2v0.892.913.646 (3)141
N6—H6D···Cl3iii0.892.913.652 (3)142
N6—H6D···Cl4iii0.892.903.609 (3)138
C3—H3B···Cl30.972.823.662 (3)146
Symmetry codes: (i) x1, y, z; (ii) x+2, y+1, z+2; (iii) x1/2, y+3/2, z+1/2; (iv) x+3/2, y+1/2, z+3/2; (v) x3/2, y+3/2, z+1/2.
 

Acknowledgements

KA is thankful to the CSIR, New Delhi [Lr: No. 01 (2570)/12/EMR-II/3.4.2012] for financial support through a major research project. The authors are thankful to the Department of Chemistry, Pondicherry University, for the single-crystal XRD instrumentation facility.

Funding information

Funding for this research was provided by: Council of Scientific and Industrial Research, India (award No. 01 (2570)/12/EMR-II/3.4.2012 to K. Anbalagan).

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