1-Cyano­methyl-4-aza-1-azonia­bicyclo­[2.2.2]octane bromide dihydrate

Cai, Y.

doi:10.1107/S1600536810019926

organic compounds

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Volume 66| Part 7| July 2010| Page o1527

doi:10.1107/S1600536810019926

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1-Cyanomethyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide dihydrate

Ying Cai ^a ^*

^aOrdered Matter Science Research Center, Southeast University, Nanjing 211189, People's Republic of China
^*Correspondence e-mail: cyik@163.com

(Received 25 May 2010; accepted 26 May 2010; online 5 June 2010)

In the crystal structure of the title compound, C₈H₁₄N₃⁺·Br⁻·2H₂O, intermolecular O—H⋯O and O—H⋯Br hydrogen bonding occurs. The water molecules are connected into chains extending in the a-axis direction. The bromide anions are connected to the water molecules, forming 10-membered rings. The cations are connected to the anions via weak C—H⋯Br interactions. Two carbon atoms of the cation are disordered and were refined using a split model (occupancy ratio 0.70:0.3).

Related literature

For uses of DABCO (1,4-biazabicyclo[2.2.2]octane) and its derivatives, see: Basaviah et al. (2003 ); Chen et al. (2010 ).

Experimental

Crystal data

C₈H₁₄N₃⁺·Br⁻·2H₂O
M_r = 268.16
Orthorhombic, P 2₁ 2₁ 2₁
a = 7.461 (5) Å
b = 12.008 (7) Å
c = 13.236 (8) Å
V = 1185.8 (13) Å³
Z = 4
Mo Kα radiation
μ = 3.45 mm⁻¹
T = 293 K
0.20 × 0.20 × 0.20 mm

Data collection

Rigaku Mercury CCD diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ) T_min = 0.701, T_max = 1.000
13047 measured reflections
2711 independent reflections
2219 reflections with I > 2σ(I)
R_int = 0.073

Refinement

R[F² > 2σ(F²)] = 0.041
wR(F²) = 0.077
S = 1.01
2711 reflections
140 parameters
101 restraints
H-atom parameters constrained
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.29 e Å⁻³
Absolute structure: Flack (1983 ), 1134 Friedel pairs
Flack parameter: 0.033 (14)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O1⋯Br1	0.82	2.58	3.354 (3)	159
O2—H1O2⋯O1	0.82	1.98	2.791 (4)	170
O1—H2O1⋯O2ⁱ	0.82	1.99	2.788 (5)	164
O2—H2O2⋯Br1ⁱ	0.82	2.50	3.314 (3)	172
C7—H7A⋯Br1	0.97	2.81	3.740 (5)	161
C7—H7B⋯Br1ⁱⁱ	0.97	2.92	3.792 (8)	151
Symmetry codes: (i) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]$ ; (ii) $[-x+{\script{1\over 2}}, -y, z+{\script{1\over 2}}]$ .

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810019926/nc2186sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810019926/nc2186Isup2.hkl

checkCIF report

Comment top

1,4-Diazabicyclo[2.2.2]octane (DABCO) is used as a organocatalyst for a large number of reactions because of its nucleophilicity (Basaviah et al., 2003) and some of its derivatives are ferroelectrics (Chen et al., 2010). The structure determination of the title compound was performed within a project on the electric properties of 1,4-Diazabicyclo[2.2.2]octane derivatives. Within this project the crystals of the title compound were obtained by accident.

In the crystal stucture of the title compound two C atoms of the cation are disordered (Fig. 1). The cations and anions are connected by weak intermolecular C—H···Br interactions. The bromide anions are additionally linked to the water molecules via intermolecular O—H···Br hydrogen bonding and the water molecules are connected into chains that elongate in the direction of the a axis (Fig. 2). Each water molecule act as hydrogen bond donor and acceptor. The bromide anions and the water molecules forming ten-membered rings.

Related literature top

For uses of DABCO (1,4-biazabicyclo[2.2.2]octane) and its derivatives, see: Basaviah et al. (2003); Chen et al. (2010).

Experimental top

1,4-Diaza-bicyclo[2.2.2]octane (dabco) (0.05?mol, 5.6?g) and bromoacetonitrile (0.1?mol, 12.00?g) were dissolved in CH₃CN(40?ml). The mixture was stirred for 1?h leading to a white precipitate of the title compound whish was filtered off, washed with acetonitrile and dried. Yield: 80%. Afterwards a mixture of 1-(cyanomethyl)-4-aza-1-azonia-bicyclo[2.2.2]octane bromide (0.01?mol 2.32?g) and tetrafluoro-borate sodium (0.01?mol 1.10?g) in H₂O (20?ml) was stirred until a clear solution was obtained. On slow evaporation of the solvent colourless plate crystals of the title compand suitable for X-ray analysis were obtained accidently.

The dielectric constant of the title compound as a function of temperature goes smoothly between 93 and 363?K and there is no dielectric anomaly observed within the measured temperature range.

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: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Crystal structure of the title compound with labelling and displacement ellipsoids drawn at the 30% probability level. Disordering is shown with full and open bonds.
	Fig. 2. Crystal structure of the title compound with view along the a axis. Disordered C and H atoms are omitted and intermolecular hydrogen bonding is shown as dashed lines.

1-Cyanomethyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide dihydrate top

Crystal data top

C₈H₁₄N₃⁺·Br⁻·2H₂O	F(000) = 552
M_r = 268.16	D_x = 1.502 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 3350 reflections
a = 7.461 (5) Å	θ = 6.3–55.2°
b = 12.008 (7) Å	µ = 3.45 mm⁻¹
c = 13.236 (8) Å	T = 293 K
V = 1185.8 (13) Å³	Prism, colourless
Z = 4	0.20 × 0.20 × 0.20 mm

Data collection top

Rigaku Mercury CCD diffractometer	2711 independent reflections
Radiation source: fine-focus sealed tube	2219 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.073
Detector resolution: 13.6620 pixels mm^-1	θ_max = 27.5°, θ_min = 3.1°
ω scans	h = −9→9
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −15→15
T_min = 0.701, T_max = 1.000	l = −17→17
13047 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.041	w = 1/[σ²(F_o²) + (0.0275P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.077	(Δ/σ)_max < 0.001
S = 1.01	Δρ_max = 0.29 e Å⁻³
2711 reflections	Δρ_min = −0.29 e Å⁻³
140 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
101 restraints	Extinction coefficient: 0.0055 (11)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 1134 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.033 (14)

Crystal data top

C₈H₁₄N₃⁺·Br⁻·2H₂O	V = 1185.8 (13) Å³
M_r = 268.16	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 7.461 (5) Å	µ = 3.45 mm⁻¹
b = 12.008 (7) Å	T = 293 K
c = 13.236 (8) Å	0.20 × 0.20 × 0.20 mm

Data collection top

Rigaku Mercury CCD diffractometer	2711 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	2219 reflections with I > 2σ(I)
T_min = 0.701, T_max = 1.000	R_int = 0.073
13047 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	H-atom parameters constrained
wR(F²) = 0.077	Δρ_max = 0.29 e Å⁻³
S = 1.01	Δρ_min = −0.29 e Å⁻³
2711 reflections	Absolute structure: Flack (1983), 1134 Friedel pairs
140 parameters	Absolute structure parameter: 0.033 (14)
101 restraints

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
N1	0.3080 (4)	0.2169 (2)	0.79551 (19)	0.0332 (7)
C1	0.3169 (6)	0.2800 (3)	0.8942 (3)	0.0470 (10)
H1A	0.3725	0.2343	0.9458	0.056*
H1B	0.1972	0.2997	0.9165	0.056*
C2	0.4287 (6)	0.3857 (3)	0.8761 (3)	0.0623 (11)
H2A	0.3617	0.4499	0.8995	0.075*
H2B	0.5381	0.3812	0.9154	0.075*
C3	0.2110 (6)	0.2873 (3)	0.7178 (3)	0.0640 (13)
H3A	0.0839	0.2899	0.7330	0.077*	0.70
H3B	0.2262	0.2556	0.6509	0.077*	0.70
H3C	0.1046	0.3208	0.7470	0.077*	0.30
H3D	0.1755	0.2422	0.6604	0.077*	0.30
C4	0.2926 (10)	0.4068 (6)	0.7216 (5)	0.053 (2)	0.70
H4A	0.3034	0.4364	0.6536	0.063*	0.70
H4B	0.2148	0.4557	0.7600	0.063*	0.70
C4'	0.349 (2)	0.3801 (15)	0.6842 (12)	0.078 (8)	0.30
H4C	0.4151	0.3555	0.6253	0.093*	0.30
H4D	0.2852	0.4480	0.6669	0.093*	0.30
C5	0.4948 (6)	0.1953 (3)	0.7609 (4)	0.0645 (12)
H5A	0.4948	0.1434	0.7048	0.077*	0.70
H5B	0.5654	0.1638	0.8154	0.077*	0.70
H5C	0.4924	0.1661	0.6926	0.077*	0.30
H5D	0.5497	0.1398	0.8042	0.077*	0.30
C6	0.5746 (11)	0.3096 (5)	0.7274 (8)	0.0645 (12)	0.70
H6A	0.6987	0.3144	0.7489	0.077*	0.70
H6B	0.5718	0.3148	0.6543	0.077*	0.70
C6'	0.6115 (17)	0.3066 (10)	0.7634 (12)	0.078 (8)	0.30
H6C	0.6908	0.3071	0.8215	0.094*	0.30
H6D	0.6830	0.3135	0.7025	0.094*	0.30
N2	0.4744 (4)	0.4012 (3)	0.7705 (3)	0.0493 (8)
C7	0.2164 (5)	0.1068 (3)	0.8091 (3)	0.0435 (9)
H7A	0.2139	0.0676	0.7450	0.052*
H7B	0.2836	0.0619	0.8568	0.052*
C8	0.0335 (6)	0.1213 (3)	0.8459 (3)	0.0488 (10)
N3	−0.1082 (6)	0.1335 (3)	0.8753 (3)	0.0724 (11)
Br1	0.08721 (5)	−0.01932 (3)	0.56114 (3)	0.05169 (15)
O1	0.4108 (4)	0.1366 (2)	0.4565 (2)	0.0779 (9)
H1O1	0.3519	0.0980	0.4953	0.117*
H2O1	0.4970	0.1418	0.4946	0.117*
O2	0.2440 (4)	0.3445 (2)	0.4497 (2)	0.0736 (9)
H1O2	0.2887	0.2823	0.4448	0.110*
H2O2	0.3207	0.3932	0.4458	0.110*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0371 (15)	0.0258 (15)	0.0368 (16)	0.0016 (13)	−0.0012 (12)	−0.0057 (12)
C1	0.061 (3)	0.042 (2)	0.038 (2)	−0.0100 (19)	0.0000 (18)	−0.0081 (16)
C2	0.063 (3)	0.049 (2)	0.074 (3)	−0.022 (3)	0.012 (3)	−0.017 (2)
C3	0.079 (3)	0.056 (3)	0.057 (2)	−0.013 (3)	−0.027 (2)	0.021 (2)
C4	0.070 (4)	0.044 (4)	0.044 (4)	0.010 (3)	0.003 (3)	0.012 (3)
C4'	0.12 (2)	0.036 (10)	0.081 (15)	−0.034 (12)	−0.028 (13)	0.018 (10)
C5	0.051 (2)	0.041 (2)	0.101 (3)	0.0023 (19)	0.032 (2)	−0.009 (2)
C6	0.051 (2)	0.041 (2)	0.101 (3)	0.0023 (19)	0.032 (2)	−0.009 (2)
C6'	0.076 (13)	0.085 (13)	0.072 (13)	−0.067 (12)	0.050 (10)	−0.046 (10)
N2	0.0519 (19)	0.0353 (17)	0.061 (2)	−0.0021 (15)	0.0030 (16)	0.0087 (16)
C7	0.051 (2)	0.0298 (19)	0.049 (2)	−0.0041 (18)	0.0025 (19)	0.0010 (16)
C8	0.052 (3)	0.042 (2)	0.052 (2)	−0.0124 (19)	−0.0037 (19)	−0.0013 (18)
N3	0.058 (3)	0.072 (3)	0.087 (3)	−0.014 (2)	0.004 (2)	−0.012 (2)
Br1	0.0441 (2)	0.0516 (2)	0.0595 (2)	0.00308 (19)	−0.00010 (19)	−0.00776 (18)
O1	0.0656 (19)	0.0689 (19)	0.099 (2)	0.0058 (19)	−0.008 (2)	0.0238 (17)
O2	0.0561 (18)	0.0486 (17)	0.116 (3)	−0.0053 (15)	−0.009 (2)	0.0014 (18)

Geometric parameters (Å, º) top

N1—C5	1.490 (5)	C4'—H4D	0.9700
N1—C7	1.499 (4)	C5—C6	1.560 (8)
N1—C1	1.511 (4)	C5—C6'	1.595 (12)
N1—C3	1.515 (5)	C5—H5A	0.9700
C1—C2	1.538 (5)	C5—H5B	0.9700
C1—H1A	0.9700	C5—H5C	0.9700
C1—H1B	0.9700	C5—H5D	0.9700
C2—N2	1.451 (5)	C6—N2	1.448 (7)
C2—H2A	0.9700	C6—H6A	0.9700
C2—H2B	0.9700	C6—H6B	0.9700
C3—C4	1.560 (8)	C6'—N2	1.532 (13)
C3—C4'	1.579 (14)	C6'—H6C	0.9700
C3—H3A	0.9700	C6'—H6D	0.9700
C3—H3B	0.9700	C7—C8	1.459 (6)
C3—H3C	0.9700	C7—H7A	0.9700
C3—H3D	0.9700	C7—H7B	0.9700
C4—N2	1.504 (8)	C8—N3	1.136 (5)
C4—H4A	0.9700	O1—H1O1	0.8201
C4—H4B	0.9700	O1—H2O1	0.8200
C4'—N2	1.500 (14)	O2—H1O2	0.8201
C4'—H4C	0.9700	O2—H2O2	0.8200

C5—N1—C7	108.0 (3)	N1—C5—C6'	111.0 (5)
C5—N1—C1	108.2 (3)	C6—C5—C6'	20.1 (9)
C7—N1—C1	111.0 (3)	N1—C5—H5A	110.3
C5—N1—C3	109.6 (3)	C6—C5—H5A	110.3
C7—N1—C3	110.8 (3)	C6'—C5—H5A	123.7
C1—N1—C3	109.2 (3)	N1—C5—H5B	110.3
N1—C1—C2	107.6 (3)	C6—C5—H5B	110.3
N1—C1—H1A	110.2	C6'—C5—H5B	90.9
C2—C1—H1A	110.2	H5A—C5—H5B	108.6
N1—C1—H1B	110.2	N1—C5—H5C	109.4
C2—C1—H1B	110.2	C6—C5—H5C	93.5
H1A—C1—H1B	108.5	C6'—C5—H5C	109.4
N2—C2—C1	112.6 (3)	H5A—C5—H5C	18.8
N2—C2—H2A	109.1	H5B—C5—H5C	124.1
C1—C2—H2A	109.1	N1—C5—H5D	109.4
N2—C2—H2B	109.1	C6—C5—H5D	127.7
C1—C2—H2B	109.1	C6'—C5—H5D	109.4
H2A—C2—H2B	107.8	H5A—C5—H5D	90.6
N1—C3—C4	107.7 (4)	H5B—C5—H5D	20.4
N1—C3—C4'	105.9 (7)	H5C—C5—H5D	108.0
C4—C3—C4'	26.6 (8)	N2—C6—C5	111.1 (5)
N1—C3—H3A	110.2	N2—C6—H6A	109.4
C4—C3—H3A	110.2	C5—C6—H6A	109.4
C4'—C3—H3A	132.1	N2—C6—H6B	109.4
N1—C3—H3B	110.2	C5—C6—H6B	109.4
C4—C3—H3B	110.2	H6A—C6—H6B	108.0
C4'—C3—H3B	86.8	N2—C6'—C5	104.9 (8)
H3A—C3—H3B	108.5	N2—C6'—H6C	110.8
N1—C3—H3C	110.6	C5—C6'—H6C	110.8
C4—C3—H3C	85.7	N2—C6'—H6D	110.8
C4'—C3—H3C	110.6	C5—C6'—H6D	110.8
H3A—C3—H3C	26.3	H6C—C6'—H6D	108.8
H3B—C3—H3C	128.5	C6—N2—C2	113.8 (5)
N1—C3—H3D	110.6	C6—N2—C4'	84.0 (10)
C4—C3—H3D	130.2	C2—N2—C4'	124.4 (7)
C4'—C3—H3D	110.6	C6—N2—C4	109.2 (5)
H3A—C3—H3D	85.1	C2—N2—C4	102.0 (4)
H3B—C3—H3D	25.6	C4'—N2—C4	27.8 (9)
H3C—C3—H3D	108.7	C6—N2—C6'	21.1 (8)
N2—C4—C3	109.0 (5)	C2—N2—C6'	96.9 (6)
N2—C4—H4A	109.9	C4'—N2—C6'	104.3 (10)
C3—C4—H4A	109.9	C4—N2—C6'	127.5 (6)
N2—C4—H4B	109.9	C8—C7—N1	111.2 (3)
C3—C4—H4B	109.9	C8—C7—H7A	109.4
H4A—C4—H4B	108.3	N1—C7—H7A	109.4
N2—C4'—C3	108.2 (9)	C8—C7—H7B	109.4
N2—C4'—H4C	110.1	N1—C7—H7B	109.4
C3—C4'—H4C	110.1	H7A—C7—H7B	108.0
N2—C4'—H4D	110.1	N3—C8—C7	179.2 (5)
C3—C4'—H4D	110.1	H1O1—O1—H2O1	94.5
H4C—C4'—H4D	108.4	H1O2—O2—H2O2	111.1
N1—C5—C6	106.9 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···Br1	0.82	2.58	3.354 (3)	159
O2—H1O2···O1	0.82	1.98	2.791 (4)	170
O1—H2O1···O2ⁱ	0.82	1.99	2.788 (5)	164
O2—H2O2···Br1ⁱ	0.82	2.50	3.314 (3)	172
C7—H7A···Br1	0.97	2.81	3.740 (5)	161
C7—H7B···Br1ⁱⁱ	0.97	2.92	3.792 (8)	151

Symmetry codes: (i) x+1/2, −y+1/2, −z+1; (ii) −x+1/2, −y, z+1/2.

Experimental details

Crystal data
Chemical formula	C₈H₁₄N₃⁺·Br⁻·2H₂O
M_r	268.16
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	293
a, b, c (Å)	7.461 (5), 12.008 (7), 13.236 (8)
V (Å³)	1185.8 (13)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	3.45
Crystal size (mm)	0.20 × 0.20 × 0.20

Data collection
Diffractometer	Rigaku Mercury CCD diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku, 2005)
T_min, T_max	0.701, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	13047, 2711, 2219
R_int	0.073
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.077, 1.01
No. of reflections	2711
No. of parameters	140
No. of restraints	101
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.29, −0.29
Absolute structure	Flack (1983), 1134 Friedel pairs
Absolute structure parameter	0.033 (14)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···Br1	0.82	2.58	3.354 (3)	158.7
O2—H1O2···O1	0.82	1.98	2.791 (4)	170.4
O1—H2O1···O2ⁱ	0.82	1.99	2.788 (5)	163.8
O2—H2O2···Br1ⁱ	0.82	2.50	3.314 (3)	171.5
C7—H7A···Br1	0.97	2.81	3.740 (5)	161
C7—H7B···Br1ⁱⁱ	0.97	2.92	3.792 (8)	151

Symmetry codes: (i) x+1/2, −y+1/2, −z+1; (ii) −x+1/2, −y, z+1/2.

References

Basaviah, D., Rao, A. J. & Satyanarayana, T. (2003). Chem. Rev. 103, 811–891. Web of Science PubMed Google Scholar
Chen, L. Z., Huang, Y., Xiong, R. G. & Hu, H. W. (2010). J. Mol. Struct. 963, 16–21. Web of Science CSD CrossRef CAS Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar

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Volume 66| Part 7| July 2010| Page o1527

doi:10.1107/S1600536810019926

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