Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Previous article
Next article
Previous article
Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Next article

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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 67| Part 8| August 2011| Pages o1929-o1930
doi:10.1107/S1600536811025992

4,7,13,18-Tetra­oxa-1,10-diazo­nia­bi­cyclo­[8.5.5]i­cosane bis­­(hexa­fluorido­phosphate)

Nalinava Sen Gupta,a* David S. Wragg,b Mats Tilsetc and Jon Petter Omtvedta

aCentre for Accelerator Based Research and Energy Physics (SAFE), Department of Chemistry, University of Oslo, PO Box 1038 Blindern, Oslo 0318, Norway, binGAP Centre for Research Based Innovation, Center for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, PO Box 1033 Blindern, Oslo 0315, Norway, and cDepartment of Chemistry, University of Oslo, PO Box 1033 Blindern, Oslo 0315, Norway
*Correspondence e-mail: n.s.gupta@kjemi.uio.no

(Received 28 March 2011; accepted 30 June 2011; online 6 July 2011)

The asymmetric unit of the title structure, C14H30N2O42+·2PF6−, contains the anion and half of the cation, the latter being completed by a crystallographic twofold axis. The cation has a cage structure with the ammonium H atoms pointing into the cage. These H atoms are shielded from inter­molecular inter­actions and form only intra­molecular contacts. There are short inter­molecular C—H⋯F inter­actions in the structure, but no conventional inter­molecular hydrogen bonds.

Related literature

For related structures, see: Cos et al. (1982[Cos, B. G., Murray-Rust, J., Murray-Rust, P., van Truong, N. & Schneider, H. (1982). Chem. Commun. pp. 377-379.]); Rehder & Wang (2003[Rehder, D. & Wang, D. (2003). Private communication.]); Luger et al. (1991[Luger, P., Buschmann, J., Knöchel, A., Tiemann, D. & Patz, M. (1991). Acta Cryst. C47, 1860-1863.]); Sen Gupta et al. (2011[Sen Gupta, N., Wragg, D. S., Tilset, M. & Omtvedt, J. P. (2011). Acta Cryst. E67. In the press.]). For discussion of a cryptand as a mol­ecular automatic titrator, see: Alibrandi et al. (2009[Alibrandi, G., Lo Vecchio, C. & Lando, G. (2009). Angew. Chem. Int. Ed. 48, 6332-6334.]). For NMR data, see: Macchioni et al. (2001[Macchioni, A., Zuccaccia, C., Clot, E., Gruet, K. & Crabtree, R. H. (2001). Organometallics, 20, 2367-2373.]); Christe & Wilson (1990[Christe, K. O. & Wilson, W. W. (1990). J. Fluorine Chem. 46, 339-342.]).

[Scheme 1]

Experimental

Crystal data

  • C14H30N2O42+·2PF6−

  • Mr = 580.34

  • Monoclinic, C 2/c

  • a = 10.8297 (16) Å

  • b = 16.485 (2) Å

  • c = 12.6846 (19) Å

  • β = 95.538 (2)°

  • V = 2254.0 (6) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.32 mm−1

  • T = 296 K

  • 0.24 × 0.06 × 0.02 mm
Data collection

  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2004[Sheldrick, G. M. (2004). SADABS. University of Göttingen, Germany.]) Tmin = 0.977, Tmax = 0.994

  • 9756 measured reflections

  • 2785 independent reflections

  • 2002 reflections with I > 2σ(I)

  • Rint = 0.039
Refinement

  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.095

  • S = 1.03

  • 2785 reflections

  • 154 parameters

  • H-atom parameters constrained

  • Δρmax = 0.40 e Å−3

  • Δρmin = −0.34 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
N1—H0⋯O1 0.91 2.34 2.826 (2) 113
N1—H0⋯O2 0.91 2.18 2.699 (2) 115
N1—H0⋯O1i 0.91 2.33 2.790 (2) 111
C2—H2A⋯F2ii 0.97 2.43 3.405 (2) 178
C6—H6B⋯F5 0.97 2.48 3.157 (2) 126
Symmetry codes: (i) [-x+1, y, -z+{\script{3\over 2}}]; (ii) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}].

Data collection: SMART (Bruker, 2001[Bruker (2001). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2001[Bruker (2001). SMART and SAINT. 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.]) and WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]); molecular graphics: DIAMOND (Brandenburg & Berndt, 1999[Brandenburg, K. & Berndt, M. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811025992/fy2005sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811025992/fy2005Isup2.hkl

checkCIF report


Comment top

Compound (I) was obtained unintentionally as the product of the attempted synthesis of a metal-encrypted tungsten(VI) complex with the [2.1.1]cryptand, 4,7,13,18-tetraoxa-1,10-diazabicyclo[8.5.5]icosane. We suspect that WCl6, being susceptable to hydrolysis, reacted with water that was present as a contaminant. Compound (I) was obtained by recrystallisation of the crude reaction product from methanol. When the same product was recrystalised from acetone, a similar diprotonated cryptand salt with SiF62- as the anion formed (Sen Gupta et al., 2011). The solvent used for recystallization was the only difference between the methods to obtain the two different crystals. The presence of both anions in the reaction product was confirmed by 19F NMR data (Macchioni et al., 2001; Christe & Wilson, 1990).

In the crystal of compound (I), the two ammonium hydrogen atoms of the diprotonated cryptand cage are pointing inwards. Cryptands are known to form proton crypts, in which the protons are very efficiently concealed inside a tight molecular cavity. No exception is observed here: the ammonium hydrogen atoms are not involved in intermolecular hydrogen bonding. They only form intramolecular contacts with the oxygen atoms of the cryptand.

Related literature top

For related structures, see: Cos et al. (1982); Rehder & Wang (2003); Luger et al. (1991); Sen Gupta et al. (2011). For discussion of a cryptand as a molecular automatic titrator, see: Alibrandi et al. (2009). For NMR data, see: Macchioni et al. (2001); Christe & Wilson (1990).

Experimental top

Reagents were purchased from Sigma-Aldrich and were used without further purification. Reactions were carried out under inert conditions by Schlenk-line techniques. The metal chloride (WCl6, 100 mg, 0.25 mmol) was allowed to stir for a minute in 10 ml toluene and then was reacted with a small excess of of AgPF6 (381 mg, 1.51 mmol) to give AgCl as a precipitate and W(PF6)6 dissolved in solution. After 30 minutes stirring, the precipitate was allowed to settle. The solution was transferred under inert conditions by cannula technique and treated with the solution of [2.1.1]cryptand (66 µl, 0.25 mmol) in 5 ml toluene for 30 minutes. The crude reaction product was obtained as dirty yellow mass after drying the solvent and it was found to be soluble in methanol. Portions of the product were recrystallized from methanol, which produced crystal (I).

Refinement top

Hydrogen Uiso's were set at 1.2 times the Ueq of the heavy atom to which the hydrogen was attached and refined in riding mode. C—H distances were fixed at 0.97 Å and the N—H distance at 0.91 Å.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and WinGX (Farrugia, 1999); molecular graphics: DIAMOND (Brandenburg & Berndt, 1999); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), with atom labels and 50% probability displacement ellipsoids for non-H atoms. The hydrogen atoms attached to the carbons are omitted for clarity. Symmetry codes: (i) –x + 1, y, –z + 3/2.
[Figure 2] Fig. 2. Packing diagram for (I), viewed along the c axis. H atoms are omitted for clarity.
4,7,13,18-Tetraoxa-1,10-diazoniabicyclo[8.5.5]icosane bis(hexafluoridophosphate) top
Crystal data top
C14H30N2O42+·2PF6−F(000) = 1192
Mr = 580.34Dx = 1.710 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1782 reflections
a = 10.8297 (16) Åθ = 2.3–28.9°
b = 16.485 (2) ŵ = 0.32 mm−1
c = 12.6846 (19) ÅT = 296 K
β = 95.538 (2)°Needle, colourless
V = 2254.0 (6) Å30.24 × 0.06 × 0.02 mm
Z = 4
Data collection top
Bruker SMART CCD area-detector
diffractometer		2785 independent reflections
Radiation source: sealed tube2002 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.039
ϕ and ω scansθmax = 28.9°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)		h = −14→14
Tmin = 0.977, Tmax = 0.994k = −22→21
9756 measured reflectionsl = −17→16
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)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0378P)2 + 1.6619P]
where P = (Fo2 + 2Fc2)/3
2785 reflections(Δ/σ)max = 0.001
154 parametersΔρmax = 0.40 e Å−3
0 restraintsΔρmin = −0.34 e Å−3
Crystal data top
C14H30N2O42+·2PF6−V = 2254.0 (6) Å3
Mr = 580.34Z = 4
Monoclinic, C2/cMo Kα radiation
a = 10.8297 (16) ŵ = 0.32 mm−1
b = 16.485 (2) ÅT = 296 K
c = 12.6846 (19) Å0.24 × 0.06 × 0.02 mm
β = 95.538 (2)°
Data collection top
Bruker SMART CCD area-detector
diffractometer		2785 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)		2002 reflections with I > 2σ(I)
Tmin = 0.977, Tmax = 0.994Rint = 0.039
9756 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.095H-atom parameters constrained
S = 1.03Δρmax = 0.40 e Å−3
2785 reflectionsΔρmin = −0.34 e Å−3
154 parameters
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
P10.47273 (5)0.15573 (3)0.99505 (4)0.02088 (14)
O10.56230 (12)0.43242 (8)0.89074 (10)0.0200 (3)
F10.46836 (11)0.12944 (8)1.11636 (9)0.0315 (3)
F20.35902 (11)0.09625 (8)0.96176 (9)0.0316 (3)
O20.39311 (12)0.59898 (8)0.80510 (11)0.0222 (3)
F60.58658 (11)0.21576 (7)1.02955 (10)0.0334 (3)
F50.37765 (11)0.22713 (7)1.01299 (11)0.0366 (3)
F30.56899 (12)0.08506 (8)0.98002 (11)0.0379 (3)
F40.47690 (13)0.18356 (9)0.87520 (10)0.0421 (4)
N10.31687 (14)0.44308 (9)0.79332 (12)0.0180 (3)
H00.38740.46840.77750.022*
C60.46254 (18)0.40126 (12)0.94552 (15)0.0217 (4)
H6A0.43390.44290.99140.026*
H6B0.49170.35560.98930.026*
C50.35700 (18)0.37461 (12)0.86707 (15)0.0203 (4)
H5A0.38310.32890.82650.024*
H5B0.28770.35730.90460.024*
C40.65712 (18)0.37384 (12)0.87734 (16)0.0225 (4)
H4A0.62160.32560.84260.027*
H4B0.69880.35830.94550.027*
C10.24085 (18)0.50610 (12)0.84409 (16)0.0218 (4)
H1A0.15360.49210.83310.026*
H1B0.26480.50790.91970.026*
C30.25267 (18)0.41362 (13)0.69006 (15)0.0227 (4)
H3A0.21310.45910.65180.027*
H3B0.18870.37500.70400.027*
C70.43045 (19)0.66749 (12)0.74776 (17)0.0257 (5)
H7A0.40190.71700.77880.031*
H7B0.39470.66460.67470.031*
C20.26190 (18)0.58770 (12)0.79590 (16)0.0238 (4)
H2A0.22860.58880.72210.029*
H2B0.22220.63000.83360.029*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
P10.0180 (3)0.0221 (3)0.0230 (3)0.0016 (2)0.0041 (2)0.0031 (2)
O10.0164 (7)0.0203 (7)0.0237 (7)0.0008 (5)0.0041 (5)0.0034 (6)
F10.0293 (7)0.0440 (8)0.0210 (6)−0.0057 (6)0.0018 (5)0.0048 (5)
F20.0312 (7)0.0350 (7)0.0281 (7)−0.0101 (6)−0.0007 (5)−0.0018 (5)
O20.0215 (7)0.0205 (7)0.0249 (7)0.0003 (6)0.0034 (6)0.0057 (6)
F60.0221 (6)0.0305 (7)0.0476 (8)−0.0053 (5)0.0031 (6)0.0034 (6)
F50.0252 (7)0.0270 (7)0.0587 (9)0.0080 (5)0.0097 (6)0.0028 (6)
F30.0338 (7)0.0298 (7)0.0523 (9)0.0105 (6)0.0158 (6)−0.0002 (6)
F40.0452 (8)0.0555 (9)0.0260 (7)−0.0063 (7)0.0063 (6)0.0133 (6)
N10.0143 (8)0.0194 (8)0.0208 (9)−0.0003 (6)0.0039 (6)−0.0006 (7)
C60.0219 (10)0.0252 (11)0.0186 (10)−0.0007 (8)0.0047 (8)0.0038 (8)
C50.0198 (10)0.0182 (10)0.0233 (10)0.0004 (8)0.0045 (8)0.0029 (8)
C40.0197 (10)0.0249 (11)0.0228 (11)0.0042 (8)0.0012 (8)0.0048 (8)
C10.0197 (10)0.0212 (10)0.0256 (11)0.0047 (8)0.0077 (8)−0.0024 (8)
C30.0174 (10)0.0281 (11)0.0221 (10)−0.0032 (8)−0.0003 (8)−0.0028 (8)
C70.0339 (12)0.0160 (10)0.0286 (11)0.0049 (8)0.0102 (9)0.0021 (8)
C20.0205 (10)0.0270 (11)0.0240 (11)0.0061 (8)0.0030 (8)0.0014 (8)
Geometric parameters (Å, º) top
P1—F31.5871 (13)C5—H5A0.9700
P1—F41.5927 (13)C5—H5B0.9700
P1—F51.5946 (13)C4—C3i1.509 (3)
P1—F21.5987 (13)C4—H4A0.9700
P1—F11.6037 (13)C4—H4B0.9700
P1—F61.6083 (13)C1—C21.504 (3)
O1—C41.432 (2)C1—H1A0.9700
O1—C61.435 (2)C1—H1B0.9700
O2—C71.423 (2)C3—C4i1.509 (3)
O2—C21.427 (2)C3—H3A0.9700
N1—C31.503 (2)C3—H3B0.9700
N1—C51.503 (2)C7—C7i1.502 (4)
N1—C11.508 (2)C7—H7A0.9700
N1—H00.9100C7—H7B0.9700
C6—C51.507 (3)C2—H2A0.9700
C6—H6A0.9700C2—H2B0.9700
C6—H6B0.9700
F3—P1—F491.00 (8)C6—C5—H5B109.6
F3—P1—F5178.59 (8)H5A—C5—H5B108.1
F4—P1—F590.10 (8)O1—C4—C3i106.57 (15)
F3—P1—F290.93 (7)O1—C4—H4A110.4
F4—P1—F290.95 (7)C3i—C4—H4A110.4
F5—P1—F289.93 (7)O1—C4—H4B110.4
F3—P1—F189.85 (7)C3i—C4—H4B110.4
F4—P1—F1178.93 (8)H4A—C4—H4B108.6
F5—P1—F189.04 (7)C2—C1—N1109.40 (15)
F2—P1—F189.68 (7)C2—C1—H1A109.8
F3—P1—F689.38 (7)N1—C1—H1A109.8
F4—P1—F689.48 (7)C2—C1—H1B109.8
F5—P1—F689.75 (7)N1—C1—H1B109.8
F2—P1—F6179.46 (8)H1A—C1—H1B108.2
F1—P1—F689.88 (7)N1—C3—C4i111.34 (16)
C4—O1—C6113.47 (14)N1—C3—H3A109.4
C7—O2—C2113.05 (15)C4i—C3—H3A109.4
C3—N1—C5112.42 (15)N1—C3—H3B109.4
C3—N1—C1111.66 (15)C4i—C3—H3B109.4
C5—N1—C1112.86 (15)H3A—C3—H3B108.0
C3—N1—H0106.5O2—C7—C7i108.31 (15)
C5—N1—H0106.5O2—C7—H7A110.0
C1—N1—H0106.5C7i—C7—H7A110.0
O1—C6—C5110.07 (15)O2—C7—H7B110.0
O1—C6—H6A109.6C7i—C7—H7B110.0
C5—C6—H6A109.6H7A—C7—H7B108.4
O1—C6—H6B109.6O2—C2—C1105.79 (15)
C5—C6—H6B109.6O2—C2—H2A110.6
H6A—C6—H6B108.2C1—C2—H2A110.6
N1—C5—C6110.33 (16)O2—C2—H2B110.6
N1—C5—H5A109.6C1—C2—H2B110.6
C6—C5—H5A109.6H2A—C2—H2B108.7
N1—C5—H5B109.6
C4—O1—C6—C5−96.35 (18)C5—N1—C1—C2149.57 (16)
C3—N1—C5—C6156.50 (15)C5—N1—C3—C4i−71.3 (2)
C1—N1—C5—C6−76.12 (19)C1—N1—C3—C4i160.72 (16)
O1—C6—C5—N1−55.1 (2)C2—O2—C7—C7i−173.23 (18)
C6—O1—C4—C3i174.66 (15)C7—O2—C2—C1170.30 (16)
C3—N1—C1—C2−82.64 (19)N1—C1—C2—O2−53.0 (2)
Symmetry code: (i) −x+1, y, −z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H0···O10.912.342.826 (2)113
N1—H0···O20.912.182.699 (2)115
N1—H0···O1i0.912.332.790 (2)111
C2—H2A···F2ii0.972.433.405 (2)178
C6—H6B···F50.972.483.157 (2)126
Symmetry codes: (i) −x+1, y, −z+3/2; (ii) −x+1/2, y+1/2, −z+3/2.

Experimental details

Crystal data
Chemical formulaC14H30N2O42+·2PF6−
Mr580.34
Crystal system, space groupMonoclinic, C2/c
Temperature (K)296
a, b, c (Å)10.8297 (16), 16.485 (2), 12.6846 (19)
β (°) 95.538 (2)
V (Å3)2254.0 (6)
Z4
Radiation typeMo Kα
µ (mm−1)0.32
Crystal size (mm)0.24 × 0.06 × 0.02
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2004)
Tmin, Tmax0.977, 0.994
No. of measured, independent and
observed [I > 2σ(I)] reflections		9756, 2785, 2002
Rint0.039
(sin θ/λ)max (Å−1)0.680
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.095, 1.03
No. of reflections2785
No. of parameters154
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.40, −0.34

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and WinGX (Farrugia, 1999), DIAMOND (Brandenburg & Berndt, 1999), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H0···O10.912.342.826 (2)113
N1—H0···O20.912.182.699 (2)115
N1—H0···O1i0.912.332.790 (2)111
C2—H2A···F2ii0.972.433.405 (2)178
C6—H6B···F50.972.483.157 (2)126
Symmetry codes: (i) −x+1, y, −z+3/2; (ii) −x+1/2, y+1/2, −z+3/2.
 

Acknowledgements

The authors thank the Norwegian Research Council for financial support (project No. 177538).

References

First citationAlibrandi, G., Lo Vecchio, C. & Lando, G. (2009). Angew. Chem. Int. Ed. 48, 6332–6334.  Web of Science CrossRef CAS Google Scholar
 First citationBrandenburg, K. & Berndt, M. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
 First citationBruker (2001). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationChriste, K. O. & Wilson, W. W. (1990). J. Fluorine Chem. 46, 339–342.  CrossRef CAS Web of Science Google Scholar
 First citationCos, B. G., Murray-Rust, J., Murray-Rust, P., van Truong, N. & Schneider, H. (1982). Chem. Commun. pp. 377–379.  Google Scholar
 First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
 First citationLuger, P., Buschmann, J., Knöchel, A., Tiemann, D. & Patz, M. (1991). Acta Cryst. C47, 1860–1863.  CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
 First citationMacchioni, A., Zuccaccia, C., Clot, E., Gruet, K. & Crabtree, R. H. (2001). Organometallics, 20, 2367–2373.  Web of Science CrossRef CAS Google Scholar
 First citationRehder, D. & Wang, D. (2003). Private communication.  Google Scholar
 First citationSen Gupta, N., Wragg, D. S., Tilset, M. & Omtvedt, J. P. (2011). Acta Cryst. E67. In the press.  CrossRef IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2004). SADABS. University of Göttingen, Germany.  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

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
Volume 67| Part 8| August 2011| Pages o1929-o1930
doi:10.1107/S1600536811025992
Follow Acta Cryst. E
Sign up for e-alerts
E-alerts
Follow Acta Cryst. on Twitter
Twitter
Follow us on facebook
Facebook
Sign up for RSS feeds
RSS