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

Journal logoIUCrDATA
ISSN: 2414-3146

Hexa­cyclo­[7.5.1.01,6.06,13.08,12.010,14]penta­decane-7,15-dione

CROSSMARK_Color_square_no_text.svg

aDepartment of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400 076, India
*Correspondence e-mail: srk@chem.iitb.ac.in

Edited by G. Smith, Queensland University of Technology, Australia (Received 1 June 2016; accepted 19 July 2016; online 26 July 2016)

The structure of the title cage compound, C15H16O2, comprises eight fused rings, viz. one four-membered, four five-membered and three six-membered. One of the inter­nal C—C bonds is unusually long for a cyclo­butane bond length [1.607 (3) Å] and is comparable with the equivalent value of 1.598 (4) Å in the unsaturated homolog hexa­cyclo­[7.4.2.01,9.03,7.04,14.06,15]penta­deca-10,12-diene-2,8-dione.

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

Structure description

Cage mol­ecules are useful synthons for the design of natural and non-natural products. Several cage systems can undergo rearrangements to generate intricate polycycles (Hopf, 2000[Hopf, H. (2000). In Classics in Hydrocarbon Chemistry: Syntheses, Concepts, Perspectives. Weinheim: Wiley-VCH.]; Osawa & Yonemitsu, 1992[Osawa, E. & Yonemitsu, O. (1992). (Editors). Carbocyclic Cage Compounds: Chemistry and Applications. New York: VCH Publishers, Inc.]). Polycyclic cage compounds have applications in medicinal chemistry for drug discovery research (Oliver & Malan, 2008[Oliver, D. W. & Malan, S. F. (2008). Med. Chem. Res. 17, 137-151.]; Geldenhuys et al. 2005[Geldenhuys, W. J., Malan, S. F., Bloomquist, J. R., Marchand, A. P. & Van der Schyf, C. J. (2005). Med. Res. Rev. 25, 21-48.]).

The carbon framework of the title compound, C15H16O2 (I), (Fig. 1[link]), comprises one four-membered, four five-membered and three six-membered rings which are fused into a closed cage structure. All of the five-membered rings adopt envelope conformations, whereas the six-membered rings have boat conformations. The mol­ecule appears as a `cage' with one edge and the dione side is open.

[Figure 1]
Figure 1
The mol­ecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

The C—C bond lengths of the cyclo­butane ring in the unsaturated hexa­cyclic system hexa­cyclo­[7.4.2.01,9.03,7.04,14. 06,15]penta­deca-10,12-diene-2,8-dione (II) (Fig. 2[link]) range from 1.559 (4) to 1.598 (4) Å (Dhaneshwar et al., 1988[Dhaneshwar, N. N., Tavale, S. S., Guru Row, T. N., Zope, U. R., Pandey, B. & Ayyangar, N. R. (1988). Acta Cryst. C44, 2191-2193.]). However, in the saturated hexa­cyclic system of (I), the C4—C5 bond is longer, with a value of 1.607 (3) Å, which is unusual among cyclo­butane bond lengths but is comparable with the corresponding bond in the related cage mol­ecule 1,7-di­allyl­penta­cyclo­[5.4.0.02,6.03,10.05,9]undecane-8,11-dione [1.612 Å; Kotha et al., 2014[Kotha, S., Seema, V., Deodhar, D. & Shaikh, M. (2014). Acta Cryst. E70, 410-414.]]. This may be because the hexa­cyclic dione system attached to the cyclo­butane ring influences the bond length of the fused carbon atoms (C4—C5).

[Figure 2]
Figure 2
The reduction of (II), giving the title compound (I)

In the crystal, only one very weak inter­molecular C6—H6⋯O3i hydrogen-bonding inter­action is present (Table 1[link]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C6—H6⋯O3i 1.00 2.58 3.547 (3) 163
Symmetry code: (i) [-x, y+{\script{1\over 2}}, -z+1].

Synthesis and crystallization

The title compound can be prepared according to Kushner (1971[Kushner, A. S. (1971). Tetrahedron Lett. 12, 3275-3278.]) via a Diels–Alder reaction of cyclo­penta­diene with either naphtha­quinone followed by [2 + 2] photo-cyclo­addition and hydrogenation or 1,2,3,4-tetra­hydro-5,8-naphtho­quinone followed by [2 + 2] photo-cyclo­addition (Kotha & Dipak, 2006[Kotha, S. & Dipak, M. K. (2006). Chem. Eur. J. 12, 4446-4450.]). After recrystallization from a 3:2 mixture of di­chloro­methane–methanol, monoclinic crystals of the hexa­cyclic dione (I) were obtained, m.p. 360–362 K (lit. m.p. 360–361 K; Kotha, 1984[Kotha, S. (1984). PhD thesis, University of Hyderabad, Hyderabad, India.]).

Melting points were recorded on Veego melting point apparatus and are uncorrected. Nuclear Magnetic Resonance (NMR) spectra were recorded on a Varian VXR 400 spectrometer operated at 400 and 100 MHz for 1H and 13C nuclei respectively.

1H NMR (400 MHz, CDCl3): δ (p.p.m.) = 2.87 (s, 4H), 2.75 (s, 2H), 2.06 (d, J = 10.7 Hz, 2H), 1.94 (t, J = 12.6 Hz, 2H), 1.60–1.53 (m, 4H), 1.34 (t, J = 7.1 Hz, 2H); 13C NMR (100 MHz, CDCl3): δ (p.p.m.) = 213.8, 55.1, 49.7, 44.2, 43.7, 41.3, 22.8, 19.3.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. The absolute structure was not determined in this analysis but the configuration for the eight arbitrarily numbered chiral centres of the mol­ecule are C4(R),C5(S),C6(R),C7(S), C10(R),C11(S),C13(R),C17(S).

Table 2
Experimental details

Crystal data
Chemical formula C15H16O2
Mr 228.29
Crystal system, space group Monoclinic, P21
Temperature (K) 100
a, b, c (Å) 8.199 (2), 7.653 (2), 8.986 (3)
β (°) 104.005 (3)
V3) 547.1 (3)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.09
Crystal size (mm) 0.60 × 0.38 × 0.18
 
Data collection
Diffractometer Rigaku Saturn724 CCD
Absorption correction Numerical (NUMABS; Rigaku, 1999[Rigaku (1999). NUMABS. Rigaku Corporation, Tokyo, Japan.])
Tmin, Tmax 0.954, 0.982
No. of measured, independent and observed [F2 > 2.0σ(F2)] reflections 5855, 2877, 1935
Rint 0.067
(sin θ/λ)max−1) 0.686
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.086, 0.85
No. of reflections 2877
No. of parameters 154
No. of restraints 1
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.27, −0.27
Computer programs: CrystalClear-SM Expert (Rigaku, 2013[Rigaku (2013). CrystalClear-SM Expert. Rigaku Corporation, Tokyo, Japan.]), SHELXS97 and SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) and CrystalStructure (Rigaku, 2010[Rigaku (2010). CrystalStructure. Rigaku Corporation, Tokyo, Japan.]).

Structural data


Computing details top

Data collection: CrystalClear-SM Expert (Rigaku, 2013); cell refinement: CrystalClear-SM Expert (Rigaku, 2013); data reduction: CrystalClear-SM Expert (Rigaku, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalStructure (Rigaku, 2010); software used to prepare material for publication: CrystalStructure (Rigaku, 2010).

Hexacyclo[7.5.1.01,6.06,13.08,12.010,14]pentadecane-7,15-dione top
Crystal data top
C15H16O2F(000) = 244.00
Mr = 228.29Dx = 1.386 Mg m3
Monoclinic, P21Melting point = 360.1–362.1 K
Hall symbol: P 2ybMo Kα radiation, λ = 0.71075 Å
a = 8.199 (2) ÅCell parameters from 1809 reflections
b = 7.653 (2) Åθ = 3.5–29.2°
c = 8.986 (3) ŵ = 0.09 mm1
β = 104.005 (3)°T = 100 K
V = 547.1 (3) Å3Prism, colourless
Z = 20.60 × 0.38 × 0.18 mm
Data collection top
Rigaku Saturn724 CCD
diffractometer
1935 reflections with F2 > 2.0σ(F2)
Detector resolution: 7.111 pixels mm-1Rint = 0.067
ω scansθmax = 29.2°
Absorption correction: numerical
(NUMABS; Rigaku, 1999)
h = 1111
Tmin = 0.954, Tmax = 0.982k = 1010
5855 measured reflectionsl = 1212
2877 independent reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.086H-atom parameters constrained
S = 0.85 w = 1/[σ2(Fo2) + (0.0183P)2]
where P = (Fo2 + 2Fc2)/3
2877 reflections(Δ/σ)max < 0.001
154 parametersΔρmax = 0.27 e Å3
1 restraintΔρmin = 0.27 e Å3
Primary atom site location: structure-invariant direct methods
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. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2.0 sigma(F2) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O20.15236 (18)0.65835 (18)0.14997 (17)0.0245 (4)
O30.21822 (19)0.35607 (16)0.36795 (16)0.0227 (4)
C10.2308 (3)0.5131 (3)0.3578 (3)0.0129 (4)
C40.2893 (3)0.6133 (3)0.2348 (3)0.0132 (5)
C50.1366 (3)0.7346 (3)0.1461 (2)0.0138 (4)
C60.0443 (3)0.7697 (3)0.3796 (3)0.0139 (5)
C70.1357 (3)0.9434 (3)0.3630 (2)0.0138 (4)
C80.2653 (3)0.7375 (3)0.0798 (3)0.0212 (5)
C90.0133 (3)0.7099 (3)0.2146 (3)0.0155 (5)
C100.3755 (3)0.7783 (3)0.3226 (3)0.0131 (4)
C110.1960 (3)0.6497 (3)0.4671 (3)0.0144 (5)
C120.4054 (3)0.6088 (3)0.0035 (3)0.0231 (5)
C130.3488 (3)0.7736 (3)0.4888 (2)0.0139 (4)
C140.3686 (3)0.5051 (3)0.1302 (3)0.0178 (5)
C150.2773 (3)0.9543 (3)0.5073 (2)0.0159 (5)
C160.1044 (3)0.7194 (3)0.0258 (2)0.0193 (5)
C170.2274 (3)0.8958 (3)0.2354 (2)0.0130 (5)
H60.04850.78170.43350.0166*
H70.06151.04880.34140.0166*
H8A0.30810.85820.05900.0255*
H8B0.23890.71950.19220.0255*
H100.49060.80810.31130.0157*
H110.17960.60010.56540.0173*
H12A0.42400.52560.08210.0277*
H12B0.51100.67520.03430.0277*
H130.44940.73900.57080.0166*
H14A0.29240.40700.08850.0213*
H14B0.47500.45450.19120.0213*
H15A0.23590.96460.60170.0191*
H15B0.35771.04950.50300.0191*
H16A0.02420.81140.07440.0231*
H16B0.05240.60450.05860.0231*
H170.25610.99430.17310.0155*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O20.0176 (8)0.0300 (8)0.0243 (9)0.0060 (7)0.0021 (7)0.0043 (7)
O30.0299 (9)0.0148 (8)0.0241 (9)0.0015 (7)0.0081 (8)0.0011 (7)
C10.0097 (10)0.0150 (10)0.0120 (11)0.0003 (9)0.0013 (9)0.0004 (8)
C40.0125 (10)0.0154 (10)0.0119 (10)0.0007 (9)0.0031 (9)0.0003 (8)
C50.0140 (10)0.0151 (10)0.0115 (10)0.0009 (9)0.0015 (8)0.0006 (9)
C60.0127 (10)0.0158 (10)0.0147 (10)0.0014 (9)0.0064 (9)0.0006 (9)
C70.0172 (10)0.0119 (10)0.0120 (10)0.0021 (10)0.0029 (9)0.0005 (8)
C80.0234 (11)0.0272 (12)0.0133 (11)0.0008 (10)0.0047 (10)0.0015 (10)
C90.0155 (10)0.0103 (10)0.0203 (11)0.0010 (9)0.0033 (9)0.0025 (9)
C100.0108 (10)0.0162 (10)0.0125 (10)0.0016 (9)0.0032 (8)0.0005 (9)
C110.0185 (11)0.0145 (10)0.0104 (10)0.0010 (9)0.0038 (9)0.0000 (9)
C120.0243 (12)0.0289 (12)0.0191 (12)0.0046 (11)0.0111 (11)0.0029 (10)
C130.0135 (10)0.0176 (10)0.0088 (10)0.0002 (9)0.0005 (8)0.0001 (9)
C140.0215 (11)0.0182 (10)0.0136 (11)0.0046 (10)0.0041 (10)0.0002 (9)
C150.0194 (11)0.0148 (10)0.0135 (10)0.0043 (9)0.0040 (9)0.0023 (9)
C160.0187 (11)0.0245 (11)0.0132 (11)0.0002 (10)0.0012 (9)0.0006 (10)
C170.0141 (10)0.0157 (11)0.0092 (10)0.0011 (9)0.0028 (8)0.0004 (8)
Geometric parameters (Å, º) top
O2—C91.213 (3)C11—C131.545 (3)
O3—C11.212 (3)C12—C141.529 (3)
C1—C41.515 (3)C13—C151.527 (3)
C1—C111.508 (3)C6—H61.000
C4—C51.607 (3)C7—H71.000
C4—C101.563 (3)C8—H8A0.990
C4—C141.513 (3)C8—H8B0.990
C5—C91.514 (3)C10—H101.000
C5—C161.507 (3)C11—H111.000
C5—C171.559 (3)C12—H12A0.990
C6—C71.551 (3)C12—H12B0.990
C6—C91.514 (3)C13—H131.000
C6—C111.592 (3)C14—H14A0.990
C7—C151.519 (3)C14—H14B0.990
C7—C171.559 (3)C15—H15A0.990
C8—C121.542 (3)C15—H15B0.990
C8—C161.518 (4)C16—H16A0.990
C10—C131.562 (3)C16—H16B0.990
C10—C171.561 (3)C17—H171.000
O3—C1—C4127.23 (19)C9—C6—H6114.135
O3—C1—C11127.2 (2)C11—C6—H6114.135
C4—C1—C11105.51 (16)C6—C7—H7115.119
C1—C4—C5107.96 (17)C15—C7—H7115.118
C1—C4—C10103.01 (16)C17—C7—H7115.120
C1—C4—C14115.82 (16)C12—C8—H8A108.685
C5—C4—C1089.22 (13)C12—C8—H8B108.683
C5—C4—C14114.08 (16)C16—C8—H8A108.691
C10—C4—C14123.09 (18)C16—C8—H8B108.689
C4—C5—C9109.73 (16)H8A—C8—H8B107.606
C4—C5—C16112.73 (17)C4—C10—H10117.129
C4—C5—C1789.09 (13)C13—C10—H10117.131
C9—C5—C16116.65 (16)C17—C10—H10117.131
C9—C5—C17102.89 (16)C1—C11—H11113.539
C16—C5—C17122.17 (17)C6—C11—H11113.536
C7—C6—C9102.03 (16)C13—C11—H11113.541
C7—C6—C11101.77 (15)C8—C12—H12A108.656
C9—C6—C11109.32 (16)C8—C12—H12B108.657
C6—C7—C15104.62 (15)C14—C12—H12A108.658
C6—C7—C17101.58 (15)C14—C12—H12B108.656
C15—C7—C17103.62 (16)H12A—C12—H12B107.600
C12—C8—C16114.29 (18)C10—C13—H13115.440
O2—C9—C5127.41 (19)C11—C13—H13115.441
O2—C9—C6127.0 (2)C15—C13—H13115.439
C5—C9—C6105.60 (16)C4—C14—H14A108.851
C4—C10—C13108.25 (16)C4—C14—H14B108.853
C4—C10—C1790.62 (13)C12—C14—H14A108.847
C13—C10—C17102.79 (16)C12—C14—H14B108.851
C1—C11—C6109.06 (15)H14A—C14—H14B107.705
C1—C11—C13103.40 (17)C7—C15—H15A112.692
C6—C11—C13102.78 (14)C7—C15—H15B112.693
C8—C12—C14114.41 (19)C13—C15—H15A112.688
C10—C13—C11100.97 (14)C13—C15—H15B112.691
C10—C13—C15103.29 (15)H15A—C15—H15B110.171
C11—C13—C15104.40 (16)C5—C16—H16A109.278
C4—C14—C12113.57 (17)C5—C16—H16B109.284
C7—C15—C1395.25 (14)C8—C16—H16A109.283
C5—C16—C8111.68 (15)C8—C16—H16B109.289
C5—C17—C7107.95 (16)H16A—C16—H16B107.945
C5—C17—C1091.07 (13)C5—C17—H17117.132
C7—C17—C10102.72 (15)C7—C17—H17117.128
C7—C6—H6114.136C10—C17—H17117.125
O3—C1—C4—C5117.82 (19)C17—C5—C9—C631.56 (16)
O3—C1—C4—C10148.72 (17)C16—C5—C17—C7139.41 (16)
O3—C1—C4—C1411.5 (3)C16—C5—C17—C10116.85 (17)
O3—C1—C11—C6116.94 (19)C17—C5—C16—C855.3 (3)
O3—C1—C11—C13134.22 (18)C7—C6—C9—O2132.44 (18)
C4—C1—C11—C664.50 (17)C7—C6—C9—C545.45 (16)
C4—C1—C11—C1344.33 (16)C9—C6—C7—C15146.90 (14)
C11—C1—C4—C563.62 (16)C9—C6—C7—C1739.33 (16)
C11—C1—C4—C1029.83 (16)C7—C6—C11—C1108.45 (15)
C11—C1—C4—C14167.07 (13)C7—C6—C11—C130.80 (18)
C1—C4—C5—C90.38 (18)C11—C6—C7—C1533.95 (18)
C1—C4—C5—C16131.45 (15)C11—C6—C7—C1773.62 (15)
C1—C4—C5—C17103.75 (14)C9—C6—C11—C11.1 (2)
C1—C4—C10—C134.89 (17)C9—C6—C11—C13108.17 (16)
C1—C4—C10—C17108.59 (14)C11—C6—C9—O2120.36 (19)
C1—C4—C14—C12172.87 (13)C11—C6—C9—C561.75 (18)
C5—C4—C10—C13103.37 (14)C6—C7—C15—C1352.83 (17)
C5—C4—C10—C170.32 (14)C6—C7—C17—C520.61 (15)
C10—C4—C5—C9103.05 (15)C6—C7—C17—C1074.74 (14)
C10—C4—C5—C16125.12 (15)C15—C7—C17—C5128.95 (13)
C10—C4—C5—C170.32 (14)C15—C7—C17—C1033.60 (16)
C5—C4—C14—C1246.6 (2)C17—C7—C15—C1353.23 (15)
C14—C4—C5—C9130.65 (16)C12—C8—C16—C555.0 (3)
C14—C4—C5—C161.2 (2)C16—C8—C12—C148.9 (3)
C14—C4—C5—C17125.97 (16)C4—C10—C13—C1120.73 (17)
C10—C4—C14—C1259.3 (2)C4—C10—C13—C15128.55 (14)
C14—C4—C10—C13138.05 (16)C4—C10—C17—C50.33 (14)
C14—C4—C10—C17118.25 (17)C4—C10—C17—C7109.01 (14)
C4—C5—C9—O2119.97 (18)C13—C10—C17—C5108.55 (13)
C4—C5—C9—C662.16 (16)C13—C10—C17—C70.13 (15)
C4—C5—C16—C848.8 (2)C17—C10—C13—C1174.24 (14)
C4—C5—C17—C7104.06 (14)C17—C10—C13—C1533.59 (16)
C4—C5—C17—C100.32 (14)C1—C11—C13—C1038.86 (15)
C9—C5—C16—C8177.11 (14)C1—C11—C13—C15145.81 (13)
C16—C5—C9—O29.8 (3)C6—C11—C13—C1074.61 (16)
C16—C5—C9—C6168.10 (14)C6—C11—C13—C1532.34 (17)
C9—C5—C17—C75.98 (16)C8—C12—C14—C441.6 (2)
C9—C5—C17—C10109.72 (13)C10—C13—C15—C753.16 (16)
C17—C5—C9—O2146.32 (17)C11—C13—C15—C752.06 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···O3i1.002.583.547 (3)163
Symmetry code: (i) x, y+1/2, z+1.
 

Acknowledgements

We would like to thank the DST for financial support. SK thanks the DST for the award of a J. C. Bose fellowship. SG and RG thank the CSIR–New Delhi and UGC–New Delhi, respectively, for the award of research fellowships. We thank Mr Darshan Mhatre for collecting the X-ray data.

References

First citationDhaneshwar, N. N., Tavale, S. S., Guru Row, T. N., Zope, U. R., Pandey, B. & Ayyangar, N. R. (1988). Acta Cryst. C44, 2191–2193.  CSD CrossRef CAS IUCr Journals Google Scholar
First citationGeldenhuys, W. J., Malan, S. F., Bloomquist, J. R., Marchand, A. P. & Van der Schyf, C. J. (2005). Med. Res. Rev. 25, 21–48.  CrossRef PubMed CAS Google Scholar
First citationHopf, H. (2000). In Classics in Hydrocarbon Chemistry: Syntheses, Concepts, Perspectives. Weinheim: Wiley-VCH.  Google Scholar
First citationKotha, S. (1984). PhD thesis, University of Hyderabad, Hyderabad, India.  Google Scholar
First citationKotha, S. & Dipak, M. K. (2006). Chem. Eur. J. 12, 4446–4450.  Web of Science CrossRef PubMed CAS Google Scholar
First citationKotha, S., Seema, V., Deodhar, D. & Shaikh, M. (2014). Acta Cryst. E70, 410–414.  CSD CrossRef IUCr Journals Google Scholar
First citationKushner, A. S. (1971). Tetrahedron Lett. 12, 3275–3278.  CrossRef Google Scholar
First citationOliver, D. W. & Malan, S. F. (2008). Med. Chem. Res. 17, 137–151.  CrossRef CAS Google Scholar
First citationOsawa, E. & Yonemitsu, O. (1992). (Editors). Carbocyclic Cage Compounds: Chemistry and Applications. New York: VCH Publishers, Inc.  Google Scholar
First citationRigaku (1999). NUMABS. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationRigaku (2010). CrystalStructure. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationRigaku (2013). CrystalClear-SM Expert. 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

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 logoIUCrDATA
ISSN: 2414-3146
Follow IUCr Journals
Sign up for e-alerts
Follow IUCr on Twitter
Follow us on facebook
Sign up for RSS feeds