Bis(4-amino­pyridinium) tetra­iodido­cad­mate monohydrate

Sun, Q.; Liao, S.; Yao, J.; Wang, J.; Fang, Q.

doi:10.1107/S1600536812034447

metal-organic compounds

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ISSN: 2056-9890

Volume 68| Part 9| September 2012| Pages m1160-m1161

doi:10.1107/S1600536812034447

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Bis(4-aminopyridinium) tetraiodidocadmate monohydrate

Qiaozhen Sun,^a ^* Songyi Liao,^a Junjun Yao,^a Junke Wang ^a and Qiongjiali Fang ^a

^aDepartment of Materials Chemistry, School of Materials Science and Engineering, Key Laboratory of Nonferrous Metal of Ministry of Education, Central South University, Changsha 410083, People's Republic of China
^*Correspondence e-mail: rosesunqz@yahoo.com.cn

(Received 11 July 2012; accepted 2 August 2012; online 8 August 2012)

The title compound, (C₅H₇N₂)₂[CdI₄]·H₂O, contains one [CdI₄]²⁻ anion, two prontonated 4-aminopyridine molecules and one water molecule in the asymmetric unit. In the anion, the Cd^II atom is coordinated by four I atoms in a slightly distorted tetrahedral geometry. The [CdI₄]²⁻ anion and the water molecule are bisected by a crystallographic mirror plane perpendicular to the c-axis direction, with the Cd^II atom, two of the I atoms and the atoms of the water molecule located on this plane. The crystal packing is stabilized by intermolecular N—H⋯I, N—H⋯O and O—H⋯I hydrogen bonds and by π–π stacking interactions [centroid–centroid distance = 3.798 (3) Å) between pyridine rings, which build up a three-dimensional network.

Related literature

For background literature on the magnetism, antiviral activity and luminescence of organic–inorganic hybrid compounds, see: Bauer et al. (2003 ); Cavicchioli et al. (2010 ); Li et al. (2007 ). For ion channel inhibitor properties of 4-aminopyridine, see: Picolo et al. (2003 ). For metal complexes of 4-aminopyridine, see: Das et al. (2010 ); Ivanova et al. (2005 ); Jebas et al. (2009 ); Kulicka et al. (2006 ); Rademeyer et al. (2007 ); Zaouali Zgolli et al. (2009 ). For bond-length data, see: Anderson et al. (2005 ); Hines et al. (2006 ).

Experimental

Crystal data

(C₅H₇N₂)₂[CdI₄]·H₂O
M_r = 828.27
Orthorhombic, P b c m
a = 7.3987 (2) Å
b = 14.7348 (4) Å
c = 18.7286 (4) Å
V = 2041.76 (9) Å³
Z = 4
Mo Kα radiation
μ = 7.12 mm⁻¹
T = 293 K
0.40 × 0.24 × 0.20 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.145, T_max = 0.340
11964 measured reflections
1860 independent reflections
1755 reflections with I > 2σ(I)
R_int = 0.052

Refinement

R[F² > 2σ(F²)] = 0.025
wR(F²) = 0.064
S = 1.02
1860 reflections
102 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.91 e Å⁻³
Δρ_min = −0.72 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯OW1ⁱ	0.86	2.03	2.886 (5)	173
N2—H2A⋯I2ⁱⁱ	0.86	3.12	3.938 (4)	161
N2—H2B⋯I2	0.86	3.04	3.843 (4)	157
OW1—HW1A⋯I2ⁱⁱ	0.83 (2)	3.24 (1)	3.828 (4)	130 (1)
OW1—HW1A⋯I2ⁱⁱⁱ	0.83 (2)	3.24 (1)	3.828 (4)	130 (1)
OW1—HW1A⋯I1	0.83 (2)	3.27 (4)	3.704 (5)	116 (3)
OW1—HW1B⋯I3^iv	0.85 (2)	2.99 (2)	3.761 (5)	152 (4)
OW1—HW1A⋯I1	0.83 (2)	3.27 (4)	3.704 (5)	116 (3)
Symmetry codes: (i) -x+1, -y+1, -z; (ii) x-1, y, z; (iii) $[x-1, y, -z+{\script{1\over 2}}]$ ; (iv) $[-x+2, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2000 ); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablock global. DOI: 10.1107/S1600536812034447/zl2495sup1.cif

checkCIF report

Comment top

Studies of hydrogen bonds connecting organic-inorganic hybrid compounds continue to be a topic of intense research in crystal engineering because such compounds not only allow for rational bottom-up construction but hydrogen bonds also effectively regulate the molecular architecture. Hydrogen bond connected organic-inorganic hybrid compounds can exhibit novel properties related to e.g magnetism, luminescence, antiviral activity and even multifunctional properties (Bauer et al., 2003; Cavicchioli et al., 2010; Li et al., 2007). The protonated form of 4-aminopyridine (4-AP) has hydrogen-bonding capability at both ends of the molecule, and it is also biologically active and can be used as a K⁺ and Ca²⁺ channel inhibitor (Picolo et al., 2003). Structures of 4-AP with the metals Mn^II, Co^II, Cu^II, Ni^II, Sn^IV, Sb^V and Pd^II have been reported (Das et al., 2010; Ivanova et al., 2005; Jebas et al., 2009; Kulicka et al., 2006; Rademeyer et al., 2007; Zaouali Zgolli et al., 2009). Here we report the crystal structure of the title compound, which is a salt that comprises two symmetry related 4-AP cations and a complex [CdI₄]^2- anion, Fig. 1. The [CdI₄]^2- anion and the water molecule are bisected by a crystallographic mirror plane perpendicular to the c-axis direction, with the the atoms Cd1, I1, I3 and the water molecule located on this plane at x, y, 1/4. In the anion, the Cd^II ion is coordinated by four I atoms, exhibiting a slightly distorted tetrahedral geometry. The mean Cd···I bond distance is 2.78 Å, which is similar to that of related compounds reported in the literature (Hines et al., 2006).

In the cation, the nitrogen atom of the pyridine ring is protonated. Both of the nitrogen atoms of 4-AP are not metal coordinated, but are instead involved in an extensive hydrogen bonding network that includes the amine hydrogen atoms and the iodine atoms, the protonated pyridyl hydrogen atom, and the water molecule. The bond distances and bond angles of the 4-AP cation are comparable with values reported earlier for its uncomplexed form (Anderson et al., 2005).

Packing of the title complex (Fig. 2 and Fig. 3) is facilitated through π–π interactions between pyridine rings [ring centroid distance: 3.798 (3) Å], through the N—H···I hydrogen bonds between the [CdI₄]^2- anions and the 4-AP cations, and through O—H···I and N—H···O hydrogen bonds, which link the components of the structure into a three dimensional network.

Related literature top

For background literature on the magnetism, antiviral activity and luminescence of organic–inorganic hybrid compounds, see: Bauer et al. (2003); Cavicchioli et al. (2010); Li et al. (2007). For ion channel inhibitor properties of 4-aminopyridine, see: Picolo et al. (2003). For metal complexes of 4-aminopyridine, see: Das et al. (2010); Ivanova et al. (2005); Jebas et al. (2009); Kulicka et al. (2006); Rademeyer et al. (2007); Zaouali Zgolli et al. (2009). For bond-length data, see: Anderson et al. (2005); Hines et al. (2006).

Experimental top

A mixture of CdI₂ (0.36 g, 0.98 mmol), pyridine-2,3-dicarboxylic acid (0.08 g, 0.48 mmol), and 4-aminopyridine (0.06 g, 0.64 mmol) in H₂O (12.0 mL) was sealed in a 20 mL stainless-steal reactor with Teflon liner and heated at 423 K for 60 h under autogenous pressure. Colorless block crystals were collected after the reaction solution was cooled. Yield: 16%. IR: 3314(s), 1653(s), 1608(s), 1526(s), 1407(s), 1197(m), 993(m), 865(w), 806(m), 758(m), 715(w), 495(m).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1 The title compound showing the atom-numbering scheme, with displacement ellipsoids shown at the 50% probability level; hydrogen atoms are drawn as spheres of arbitrary radius. Hydrogen bonds are shown as dashed lines. [Symmetry codes: (i) x, y, -z+0.5; (ii) -x+1, -y+1, 0.5+z]

Fig. 2 A packing diagram of the title compound, viewed in perspective along the a axis.

Fig. 3 A view of the various N—H···I, N—H···O and O—H···I hydrogen bonds in the (1 1 2) plane, with hydrogen bonds shown as dashed lines. [Symmetry codes: (i) -x+1, -y+1, -z; (ii) -x+2, -y+1, -z; (iii) -x+2, -y+1, z-0.5; (iv) x-1, -y+0.5, z-0.5; (v) x-1, y, z.]

Bis(4-aminopyridinium) tetraiodidocadmate monohydrate top

Crystal data top

(C₅H₇N₂)₂[CdI₄]·H₂O	F(000) = 1488
M_r = 828.27	D_x = 2.694 Mg m⁻³
Orthorhombic, Pbcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P2c2b	Cell parameters from 7689 reflections
a = 7.3987 (2) Å	θ = 2.6–28.2°
b = 14.7348 (4) Å	µ = 7.12 mm⁻¹
c = 18.7286 (4) Å	T = 293 K
V = 2041.76 (9) Å³	Block, colourless
Z = 4	0.40 × 0.24 × 0.20 mm

Data collection top

Bruker SMART CCD diffractometer	1860 independent reflections
Radiation source: fine-focus sealed tube	1755 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.052
ϕ and ω scans	θ_max = 25.0°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→8
T_min = 0.145, T_max = 0.340	k = −17→14
11964 measured reflections	l = −22→22

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.025	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.064	w = 1/[σ²(F_o²) + (0.0406P)² + 1.5671P] where P = (F_o² + 2F_c²)/3
S = 1.02	(Δ/σ)_max = 0.001
1860 reflections	Δρ_max = 0.91 e Å⁻³
102 parameters	Δρ_min = −0.72 e Å⁻³
3 restraints	Extinction correction: SHELXTL (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00433 (17)

Crystal data top

(C₅H₇N₂)₂[CdI₄]·H₂O	V = 2041.76 (9) Å³
M_r = 828.27	Z = 4
Orthorhombic, Pbcm	Mo Kα radiation
a = 7.3987 (2) Å	µ = 7.12 mm⁻¹
b = 14.7348 (4) Å	T = 293 K
c = 18.7286 (4) Å	0.40 × 0.24 × 0.20 mm

Data collection top

Bruker SMART CCD diffractometer	1860 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1755 reflections with I > 2σ(I)
T_min = 0.145, T_max = 0.340	R_int = 0.052
11964 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.025	3 restraints
wR(F²) = 0.064	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	Δρ_max = 0.91 e Å⁻³
1860 reflections	Δρ_min = −0.72 e Å⁻³
102 parameters

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 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 > 2sigma(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
Cd1	1.01826 (6)	0.20199 (3)	0.2500	0.03793 (14)
I1	0.64576 (5)	0.22518 (3)	0.2500	0.03959 (14)
I2	1.14547 (4)	0.28284 (2)	0.125323 (15)	0.04579 (13)
I3	1.11401 (5)	0.01921 (3)	0.2500	0.04403 (15)
N1	0.6396 (7)	0.4593 (3)	−0.11682 (19)	0.0606 (12)
H1B	0.6371	0.4870	−0.1572	0.073*
N2	0.6522 (6)	0.3361 (3)	0.0766 (2)	0.0617 (11)
H2A	0.5548	0.3145	0.0950	0.074*
H2B	0.7526	0.3324	0.0996	0.074*
C1	0.4861 (8)	0.4240 (3)	−0.0903 (2)	0.0588 (13)
H1A	0.3794	0.4282	−0.1163	0.071*
C2	0.4861 (6)	0.3821 (3)	−0.0254 (2)	0.0467 (10)
H2C	0.3797	0.3583	−0.0067	0.056*
C3	0.6476 (6)	0.3755 (3)	0.0125 (2)	0.0407 (9)
C4	0.8047 (7)	0.4105 (3)	−0.0187 (3)	0.0547 (11)
H4A	0.9155	0.4048	0.0043	0.066*
C5	0.7938 (8)	0.4524 (3)	−0.0821 (3)	0.0626 (13)
H5A	0.8977	0.4772	−0.1021	0.075*
OW1	0.4000 (7)	0.4442 (3)	0.2500	0.0552 (11)
HW1A	0.355 (5)	0.3924 (19)	0.2500	0.083*
HW1B	0.514 (3)	0.439 (3)	0.2500	0.083*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.0368 (3)	0.0395 (3)	0.0375 (2)	0.00051 (18)	0.000	0.000
I1	0.0341 (2)	0.0429 (2)	0.0418 (2)	0.00329 (15)	0.000	0.000
I2	0.0395 (2)	0.0539 (2)	0.04392 (19)	0.00186 (12)	0.00688 (10)	0.01025 (11)
I3	0.0430 (3)	0.0383 (2)	0.0508 (2)	0.00445 (16)	0.000	0.000
N1	0.101 (4)	0.046 (2)	0.0349 (18)	−0.001 (2)	0.0029 (19)	0.0039 (16)
N2	0.059 (3)	0.072 (3)	0.054 (2)	−0.008 (2)	−0.0031 (17)	0.022 (2)
C1	0.077 (4)	0.049 (3)	0.051 (2)	0.002 (3)	−0.018 (2)	−0.009 (2)
C2	0.048 (3)	0.044 (2)	0.048 (2)	−0.002 (2)	−0.0030 (19)	−0.0044 (18)
C3	0.047 (3)	0.033 (2)	0.042 (2)	0.0019 (17)	0.0029 (16)	0.0002 (16)
C4	0.048 (3)	0.056 (3)	0.061 (3)	0.002 (2)	0.008 (2)	0.006 (2)
C5	0.071 (4)	0.061 (3)	0.056 (3)	0.000 (3)	0.023 (3)	0.001 (2)
OW1	0.067 (3)	0.051 (3)	0.047 (2)	0.001 (2)	0.000	0.000

Geometric parameters (Å, º) top

Cd1—I1	2.7771 (6)	C1—C2	1.363 (6)
Cd1—I3	2.7849 (6)	C1—H1A	0.9300
Cd1—I2ⁱ	2.7852 (4)	C2—C3	1.394 (6)
Cd1—I2	2.7852 (4)	C2—H2C	0.9300
N1—C5	1.317 (7)	C3—C4	1.400 (6)
N1—C1	1.345 (7)	C4—C5	1.341 (7)
N1—H1B	0.8600	C4—H4A	0.9300
N2—C3	1.333 (5)	C5—H5A	0.9300
N2—H2A	0.8600	OW1—HW1A	0.83 (2)
N2—H2B	0.8600	OW1—HW1B	0.85 (2)

I1—Cd1—I3	111.805 (18)	C2—C1—H1A	119.8
I1—Cd1—I2ⁱ	106.423 (13)	C1—C2—C3	119.1 (5)
I3—Cd1—I2ⁱ	109.129 (13)	C1—C2—H2C	120.5
I1—Cd1—I2	106.423 (13)	C3—C2—H2C	120.5
I3—Cd1—I2	109.129 (13)	N2—C3—C2	120.8 (4)
I2ⁱ—Cd1—I2	113.94 (2)	N2—C3—C4	121.0 (4)
C5—N1—C1	121.2 (4)	C2—C3—C4	118.3 (4)
C5—N1—H1B	119.4	C5—C4—C3	119.3 (5)
C1—N1—H1B	119.4	C5—C4—H4A	120.3
C3—N2—H2A	120.0	C3—C4—H4A	120.3
C3—N2—H2B	120.0	N1—C5—C4	121.7 (5)
H2A—N2—H2B	120.0	N1—C5—H5A	119.1
N1—C1—C2	120.3 (5)	C4—C5—H5A	119.1
N1—C1—H1A	119.8	HW1A—OW1—HW1B	108 (3)

Symmetry code: (i) x, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···OW1ⁱⁱ	0.86	2.03	2.886 (5)	173
N2—H2A···I2ⁱⁱⁱ	0.86	3.12	3.938 (4)	161
N2—H2B···I2	0.86	3.04	3.843 (4)	157
OW1—HW1A···I2ⁱⁱⁱ	0.83 (2)	3.24 (1)	3.828 (4)	130 (1)
OW1—HW1A···I2^iv	0.83 (2)	3.24 (1)	3.828 (4)	130 (1)
OW1—HW1A···I1	0.83 (2)	3.27 (4)	3.704 (5)	116 (3)
OW1—HW1B···I3^v	0.85 (2)	2.99 (2)	3.761 (5)	152 (4)
OW1—HW1A···I1	0.83 (2)	3.27 (4)	3.704 (5)	116 (3)

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

Experimental details

Crystal data
Chemical formula	(C₅H₇N₂)₂[CdI₄]·H₂O
M_r	828.27
Crystal system, space group	Orthorhombic, Pbcm
Temperature (K)	293
a, b, c (Å)	7.3987 (2), 14.7348 (4), 18.7286 (4)
V (Å³)	2041.76 (9)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	7.12
Crystal size (mm)	0.40 × 0.24 × 0.20

Data collection
Diffractometer	Bruker SMART CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.145, 0.340
No. of measured, independent and observed [I > 2σ(I)] reflections	11964, 1860, 1755
R_int	0.052
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.064, 1.02
No. of reflections	1860
No. of parameters	102
No. of restraints	3
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.91, −0.72

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···OW1ⁱ	0.86	2.03	2.886 (5)	173.2
N2—H2A···I2ⁱⁱ	0.86	3.12	3.938 (4)	160.5
N2—H2B···I2	0.86	3.04	3.843 (4)	157.2
OW1—HW1A···I2ⁱⁱ	0.83 (2)	3.236 (14)	3.828 (4)	130.4 (12)
OW1—HW1A···I2ⁱⁱⁱ	0.83 (2)	3.236 (14)	3.828 (4)	130.4 (12)
OW1—HW1A···I1	0.83 (2)	3.27 (4)	3.704 (5)	116 (3)
OW1—HW1B···I3^iv	0.85 (2)	2.99 (2)	3.761 (5)	152 (4)
OW1—HW1A···I1	0.83 (2)	3.27 (4)	3.704 (5)	116 (3)

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

Acknowledgements

The authors acknowledge financial support from the Postdoctoral Science Foundation of Central South University and the Fundamental Research Funds for the Central Universities.

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