trans-Diaqua­bis­[5-(pyridine-3-carboxamido)­tetra­zolido-κ2O,N1]zinc dihydrate

Li, F.; Ou, X.-P.; Huang, C.-C.

doi:10.1107/S1600536812014997

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 5| May 2012| Pages m653-m654

doi:10.1107/S1600536812014997

Open

access

trans-Diaquabis[5-(pyridine-3-carboxamido)tetrazolido-κ²O,N¹]zinc dihydrate

Fang Li,^a Xiang-Ping Ou ^a and Chang-Cang Huang ^a ^*

^aState Key Laboratory Breeding Base of Photocatalysis, College of Chemistry & Chemical Engineering, Fuzhou University, Fuzhou, Fujian 350108, People's Republic of China
^*Correspondence e-mail: cchuang@fzu.edu.cn

(Received 24 March 2012; accepted 5 April 2012; online 21 April 2012)

The title compound, [Zn(C₇H₅N₆O)₂(H₂O)₂]·2H₂O, consists of one Zn^II ion located on the crystallographic inversion centre, two 5-(pyridine-3-carboxamido)tetrazolide ligands, two coordinated water molecules and two free water molecules. The Zn^II ion adopts a slightly distorted octahedral coordination geometry formed by the N,O-chelating ligands and two O water atoms. The pyridine N atoms are not coordinated. In the crystal, complex molecules are connected by N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds, forming a three-dimensional network.

Related literature

For pharmaceutical applications of amide derivatives, see: Foster et al. (1999 ); Rauko et al. (2001 ); Rowland et al. (2001 , 2002 ). For our recent work on the design and synthesis of amide complexes, see: Wang et al. (2010 ). For the use of nicotinoylamino in building novel complexes, see: Aakeröy et al. (2001 ); Li et al. (2008 ); Moncol et al. (2007 ); Kumar et al. (2005 ). For Zn—N and Zn—O bond lengths in related structures, see: Armstrong et al. (2003 ); Liu et al. (2009 ).

Experimental

Crystal data

[Zn(C₇H₅N₆O)₂(H₂O)₂]·2H₂O
M_r = 515.79
Monoclinic, P 2₁ /n
a = 7.2576 (15) Å
b = 12.008 (2) Å
c = 11.917 (2) Å
β = 97.76 (3)°
V = 1029.1 (3) Å³
Z = 2
Mo Kα radiation
μ = 1.26 mm⁻¹
T = 293 K
0.22 × 0.15 × 0.1 mm

Data collection

Rigaku Saturn 724 CCD area-detector diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2002 ) T_min = 0.819, T_max = 1.000
8464 measured reflections
2374 independent reflections
2188 reflections with I > 2σ(I)
R_int = 0.043

Refinement

R[F² > 2σ(F²)] = 0.045
wR(F²) = 0.100
S = 1.19
2374 reflections
165 parameters
6 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Table 1
Selected bond lengths (Å)

Zn1—N2	2.058 (2)
Zn1—O2	2.131 (2)
Zn1—O1	2.1470 (17)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H6⋯O3	0.86	2.04	2.829 (3)	153
O2—H2A⋯N5ⁱ	0.84 (1)	1.97 (1)	2.795 (3)	165 (3)
O2—H2B⋯N6ⁱⁱ	0.84 (1)	1.89 (1)	2.727 (3)	178 (3)
O3—H3A⋯O2ⁱ	0.84 (1)	2.08 (2)	2.843 (3)	152 (4)
O3—H3B⋯N4ⁱⁱⁱ	0.84 (1)	2.09 (1)	2.907 (3)	164 (4)
Symmetry codes: (i) -x+1, -y, -z; (ii) $[x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iii) $[-x+{\script{3\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: CrystalClear (Rigaku, 2002); cell refinement: CrystalClear; data reduction: CrystalClear; 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 datablocks I, global. DOI: 10.1107/S1600536812014997/hg5200sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812014997/hg5200Isup2.hkl

checkCIF report

Comment top

In recent years, many metal compounds derived from amides, have been prepared and characterized, and have been found to possess a wide variety of pharmic applications (Foster et al., 1999; Rauko et al., 2001; Rowland et al., 2001; Rowland et al., 2002). Amides were used to construct extended frameworks sustained both by hydrogen bonds and coordination bonds owing to the inherent coordination and hydrogenbonding donor/acceptor functionalities (Aakeröy et al., 2001; Li et al., 2008; Moncol et al., 2007; Kumar et al., 2005). In this paper, we report the crystal structure of the zinc-amide complex.

The asymmetric unit of complex, (I), contains one Zn^II ion located on an inversion centre, one independent N-(tetrazol-5-yl)-nicotinamide ligand, one coordination water molecule and one free water molecule. The central Zn^II ion adopts a slightly distorted octahedral coordination geometry by two ligands and two coordination water molecules. The equatorial plane is formed by two tetrazole N atoms and two O atoms in bis-N, O-chelating coordination from two N-(tetrazol-5-yl)-nicotinamide ligands, while the axial positions are occupied by two O atoms from two coordination water molecules. The Zn–N bond length is 2.058 (2) Å. The bond lengths of Zn–O are in the range 2.131 (2)–2.147 (1) Å. All the Zn–N or Zn–O bond lengths are comparable to those reported previously for zinc compounds (Armstrong et al., 2003; Liu et al., 2009). The dihedral angle between tetrazole and pyridine groups is 45.988 (1)°.

In the crystal, the complex molecules are connected to a two dimensional layer by intermolecular N–H···O_free (O atoms from free water molecules) hydrogen bonds (Fig. 2, Table 2). The layered strcture form a three-dimensional network via O_free–H···O_coord (O atoms from coordination water molecules), O_free–H···N and O_coord–H···N hydrogen bonds.

Related literature top

For pharmaceutical applications of amide derivatives, see: Foster et al. (1999); Rauko et al. (2001); Rowland et al. (2001, 2002). For our recent work on the design and synthesis of amide complexes, see: Wang et al. (2010). For the use of nicotinoylamino in building novel complexes, see: Aakeröy et al. (2001); Li et al. (2008); Moncol et al. (2007); Kumar et al. (2005). For Zn—N and Zn—O bond lengths in related structures, see: Armstrong et al. (2003); Liu et al. (2009).

Experimental top

The title compound was synthesized by reacting the ligand (N-(1H-tetrazol-5-yl)-nicotinamide) (0.019 g,0.01 mmol) with Zn(CH₃COO)₂^.2H₂O (0.011 g, 0.05 mmol) in 5.0 ml of dimethyl sulfoxide followed by the addition of 4 ml of ethanol. The muddy solution obtained was stirred at room temperature for three hours, filtered and set aside to slowly crystallize at room temperature. The block-like crystals were obtained after about three weeks.

Computing details top

Data collection: CrystalClear (Rigaku, 2002); cell refinement: CrystalClear (Rigaku, 2002); data reduction: CrystalClear (Rigaku, 2002); 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. View of the coordination environment of Zn²⁺ in title compound at 50%. H atoms have been omitted for clarity. [Symmetry codes: (i) -x, -y, -z.]
	Fig. 2. A view of the two-dimensional structure formed via hydrogen bonds.

trans-Diaquabis[5-(pyridine-3-carboxamido)tetrazolido- κ²O,N¹]zinc dihydrate top

Crystal data top

[Zn(C₇H₅N₆O)₂(H₂O)₂]·2H₂O	F(000) = 528
M_r = 515.79	D_x = 1.665 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3552 reflections
a = 7.2576 (15) Å	θ = 3.1–27.5°
b = 12.008 (2) Å	µ = 1.26 mm⁻¹
c = 11.917 (2) Å	T = 293 K
β = 97.76 (3)°	Prism, colorless
V = 1029.1 (3) Å³	0.22 × 0.15 × 0.1 mm
Z = 2

Data collection top

Rigaku Saturn 724 CCD area-detector diffractometer	2374 independent reflections
Radiation source: fine-focus sealed tube	2188 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.043
scintillation counter scans	θ_max = 27.6°, θ_min = 3.3°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2002)	h = −9→7
T_min = 0.819, T_max = 1.000	k = −15→14
8464 measured reflections	l = −15→15

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.100	H atoms treated by a mixture of independent and constrained refinement
S = 1.19	w = 1/[σ²(F_o²) + (0.0354P)² + 0.6596P] where P = (F_o² + 2F_c²)/3
2374 reflections	(Δ/σ)_max = 0.042
165 parameters	Δρ_max = 0.24 e Å⁻³
6 restraints	Δρ_min = −0.33 e Å⁻³

Crystal data top

[Zn(C₇H₅N₆O)₂(H₂O)₂]·2H₂O	V = 1029.1 (3) Å³
M_r = 515.79	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 7.2576 (15) Å	µ = 1.26 mm⁻¹
b = 12.008 (2) Å	T = 293 K
c = 11.917 (2) Å	0.22 × 0.15 × 0.1 mm
β = 97.76 (3)°

Data collection top

Rigaku Saturn 724 CCD area-detector diffractometer	2374 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku, 2002)	2188 reflections with I > 2σ(I)
T_min = 0.819, T_max = 1.000	R_int = 0.043
8464 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	6 restraints
wR(F²) = 0.100	H atoms treated by a mixture of independent and constrained refinement
S = 1.19	Δρ_max = 0.24 e Å⁻³
2374 reflections	Δρ_min = −0.33 e Å⁻³
165 parameters

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
Zn1	0.0000	0.0000	0.0000	0.02817 (14)
O1	0.1128 (2)	0.16405 (14)	−0.01319 (16)	0.0348 (4)
C5	0.2633 (3)	0.3319 (2)	0.0481 (2)	0.0274 (5)
C7	0.3943 (3)	0.0364 (2)	0.1181 (2)	0.0259 (5)
C6	0.2446 (3)	0.2086 (2)	0.0460 (2)	0.0281 (5)
N4	0.5071 (3)	−0.12357 (19)	0.1550 (2)	0.0364 (5)
N5	0.5487 (3)	−0.01344 (18)	0.1645 (2)	0.0342 (5)
N6	0.3527 (3)	0.49961 (18)	0.1502 (2)	0.0370 (5)
C4	0.3380 (4)	0.3890 (2)	0.1451 (2)	0.0333 (6)
H12	0.3799	0.3480	0.2097	0.040*
C3	0.1991 (4)	0.3936 (2)	−0.0474 (2)	0.0349 (6)
H13	0.1448	0.3584	−0.1132	0.042*
C1	0.2944 (4)	0.5576 (2)	0.0566 (2)	0.0377 (6)
H15	0.3064	0.6347	0.0586	0.045*
C2	0.2168 (4)	0.5077 (2)	−0.0436 (3)	0.0415 (7)
H16	0.1772	0.5506	−0.1072	0.050*
N1	0.3798 (3)	0.15158 (17)	0.11143 (18)	0.0309 (5)
H6	0.4637	0.1899	0.1523	0.037*
N3	0.3383 (3)	−0.13789 (18)	0.1054 (2)	0.0344 (5)
N2	0.2617 (3)	−0.03656 (18)	0.08075 (18)	0.0279 (4)
O2	0.0833 (3)	−0.05113 (17)	−0.15682 (16)	0.0340 (4)
H2A	0.186 (2)	−0.025 (3)	−0.169 (3)	0.066 (12)*
H2B	0.011 (3)	−0.037 (3)	−0.2160 (16)	0.061 (11)*
O3	0.7255 (3)	0.25284 (18)	0.1891 (2)	0.0517 (6)
H3A	0.801 (4)	0.208 (3)	0.166 (3)	0.078*
H3B	0.787 (4)	0.287 (3)	0.243 (2)	0.078*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Zn1	0.0224 (2)	0.0244 (2)	0.0352 (2)	−0.00194 (15)	−0.00520 (16)	−0.00004 (16)
O1	0.0314 (10)	0.0247 (9)	0.0444 (11)	−0.0060 (7)	−0.0087 (8)	0.0033 (8)
C5	0.0270 (12)	0.0251 (12)	0.0292 (12)	−0.0025 (9)	0.0006 (10)	−0.0005 (10)
C7	0.0250 (12)	0.0264 (11)	0.0248 (11)	−0.0005 (9)	−0.0015 (9)	0.0007 (9)
C6	0.0298 (13)	0.0257 (12)	0.0284 (12)	−0.0027 (10)	0.0020 (10)	0.0018 (10)
N4	0.0299 (12)	0.0346 (12)	0.0426 (13)	0.0043 (9)	−0.0025 (10)	0.0052 (10)
N5	0.0297 (12)	0.0320 (12)	0.0382 (13)	−0.0006 (9)	−0.0055 (9)	0.0048 (9)
N6	0.0414 (14)	0.0302 (12)	0.0374 (12)	−0.0022 (10)	−0.0019 (10)	−0.0053 (9)
C4	0.0377 (15)	0.0295 (13)	0.0313 (13)	−0.0005 (11)	−0.0007 (11)	−0.0019 (10)
C3	0.0400 (15)	0.0312 (13)	0.0312 (13)	−0.0004 (11)	−0.0030 (11)	−0.0018 (10)
C1	0.0411 (16)	0.0248 (13)	0.0466 (17)	−0.0026 (11)	0.0042 (13)	−0.0005 (11)
C2	0.0529 (18)	0.0323 (15)	0.0372 (15)	0.0014 (12)	−0.0014 (13)	0.0083 (11)
N1	0.0290 (11)	0.0254 (10)	0.0348 (11)	−0.0046 (9)	−0.0083 (9)	−0.0016 (9)
N3	0.0317 (12)	0.0257 (11)	0.0437 (13)	0.0020 (9)	−0.0026 (10)	0.0036 (9)
N2	0.0253 (11)	0.0243 (10)	0.0325 (11)	−0.0001 (8)	−0.0023 (9)	0.0008 (8)
O2	0.0280 (10)	0.0396 (11)	0.0332 (10)	−0.0005 (8)	−0.0005 (8)	−0.0006 (8)
O3	0.0387 (12)	0.0347 (12)	0.0765 (17)	−0.0038 (9)	−0.0109 (11)	−0.0120 (10)

Geometric parameters (Å, º) top

Zn1—N2	2.058 (2)	N4—N5	1.358 (3)
Zn1—N2ⁱ	2.058 (2)	N6—C4	1.333 (3)
Zn1—O2ⁱ	2.131 (2)	N6—C1	1.334 (4)
Zn1—O2	2.131 (2)	C4—H12	0.9300
Zn1—O1	2.1470 (17)	C3—C2	1.376 (4)
Zn1—O1ⁱ	2.1470 (17)	C3—H13	0.9300
O1—C6	1.232 (3)	C1—C2	1.386 (4)
C5—C3	1.385 (4)	C1—H15	0.9300
C5—C4	1.389 (3)	C2—H16	0.9300
C5—C6	1.487 (3)	N1—H6	0.8600
C7—N5	1.323 (3)	N3—N2	1.353 (3)
C7—N2	1.332 (3)	O2—H2A	0.840 (5)
C7—N1	1.389 (3)	O2—H2B	0.839 (5)
C6—N1	1.354 (3)	O3—H3A	0.837 (5)
N4—N3	1.298 (3)	O3—H3B	0.838 (5)

N2—Zn1—N2ⁱ	180.00 (16)	C7—N5—N4	103.8 (2)
N2—Zn1—O2ⁱ	90.26 (8)	C4—N6—C1	117.9 (2)
N2ⁱ—Zn1—O2ⁱ	89.74 (8)	N6—C4—C5	123.3 (2)
N2—Zn1—O2	89.74 (8)	N6—C4—H12	118.3
N2ⁱ—Zn1—O2	90.26 (8)	C5—C4—H12	118.3
O2ⁱ—Zn1—O2	180.0	C2—C3—C5	119.0 (3)
N2—Zn1—O1	83.86 (8)	C2—C3—H13	120.5
N2ⁱ—Zn1—O1	96.14 (8)	C5—C3—H13	120.5
O2ⁱ—Zn1—O1	87.47 (8)	N6—C1—C2	122.7 (2)
O2—Zn1—O1	92.53 (8)	N6—C1—H15	118.6
N2—Zn1—O1ⁱ	96.14 (8)	C2—C1—H15	118.6
N2ⁱ—Zn1—O1ⁱ	83.86 (8)	C3—C2—C1	119.0 (3)
O2ⁱ—Zn1—O1ⁱ	92.53 (8)	C3—C2—H16	120.5
O2—Zn1—O1ⁱ	87.47 (8)	C1—C2—H16	120.5
O1—Zn1—O1ⁱ	180.00 (11)	C6—N1—C7	125.5 (2)
C6—O1—Zn1	129.12 (16)	C6—N1—H6	117.3
C3—C5—C4	118.1 (2)	C7—N1—H6	117.3
C3—C5—C6	120.0 (2)	N4—N3—N2	108.3 (2)
C4—C5—C6	122.0 (2)	C7—N2—N3	105.2 (2)
N5—C7—N2	112.0 (2)	C7—N2—Zn1	126.55 (18)
N5—C7—N1	121.8 (2)	N3—N2—Zn1	128.27 (16)
N2—C7—N1	126.1 (2)	Zn1—O2—H2A	114 (2)
O1—C6—N1	123.8 (2)	Zn1—O2—H2B	117 (2)
O1—C6—C5	120.3 (2)	H2A—O2—H2B	104.1 (12)
N1—C6—C5	115.9 (2)	H3A—O3—H3B	104.7 (13)
N3—N4—N5	110.7 (2)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H6···O3	0.86	2.04	2.829 (3)	153
O2—H2A···N5ⁱⁱ	0.84 (1)	1.97 (1)	2.795 (3)	165 (3)
O2—H2B···N6ⁱⁱⁱ	0.84 (1)	1.89 (1)	2.727 (3)	178 (3)
O3—H3A···O2ⁱⁱ	0.84 (1)	2.08 (2)	2.843 (3)	152 (4)
O3—H3B···N4^iv	0.84 (1)	2.09 (1)	2.907 (3)	164 (4)

Symmetry codes: (ii) −x+1, −y, −z; (iii) x−1/2, −y+1/2, z−1/2; (iv) −x+3/2, y+1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	[Zn(C₇H₅N₆O)₂(H₂O)₂]·2H₂O
M_r	515.79
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	293
a, b, c (Å)	7.2576 (15), 12.008 (2), 11.917 (2)
β (°)	97.76 (3)
V (Å³)	1029.1 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	1.26
Crystal size (mm)	0.22 × 0.15 × 0.1

Data collection
Diffractometer	Rigaku Saturn 724 CCD area-detector diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku, 2002)
T_min, T_max	0.819, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	8464, 2374, 2188
R_int	0.043
(sin θ/λ)_max (Å⁻¹)	0.651

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.100, 1.19
No. of reflections	2374
No. of parameters	165
No. of restraints	6
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.24, −0.33

Computer programs: CrystalClear (Rigaku, 2002), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top

Zn1—N2	2.058 (2)	Zn1—O1	2.1470 (17)
Zn1—O2	2.131 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H6···O3	0.86	2.04	2.829 (3)	152.8
O2—H2A···N5ⁱ	0.840 (5)	1.974 (9)	2.795 (3)	165 (3)
O2—H2B···N6ⁱⁱ	0.839 (5)	1.889 (6)	2.727 (3)	178 (3)
O3—H3A···O2ⁱ	0.837 (5)	2.08 (2)	2.843 (3)	152 (4)
O3—H3B···N4ⁱⁱⁱ	0.838 (5)	2.092 (13)	2.907 (3)	164 (4)

Symmetry codes: (i) −x+1, −y, −z; (ii) x−1/2, −y+1/2, z−1/2; (iii) −x+3/2, y+1/2, −z+1/2.

References

Aakeröy, C. B., Beatty, A. M. & Helfrich, B. A. (2001). Angew. Chem. Int. Ed. 40, 3240–3242. Web of Science CrossRef CAS Google Scholar
Armstrong, C. M., Bernhardt, P. V., Chin, P. & Richardson, D. R. (2003). Eur. J. Inorg. Chem. pp. 1145–1156. CSD CrossRef Google Scholar
Foster, J. E., Nicholson, J. M., Butcher, R., Stables, J. P., Edafiogho, I. O., Goodwin, A. M., Henson, M. C., Smith, C. A. & Scott, K. R. (1999). Bioorg. Med. Chem. 7, 2415–2425. Web of Science CSD CrossRef PubMed CAS Google Scholar
Kumar, D. K., Jose, D. A., Das, A. & Dastidar, P. (2005). Inorg. Chem. 44, 6933–6935. Web of Science CSD CrossRef PubMed CAS Google Scholar
Li, C., Chen, M. & Shao, C. (2008). Acta Cryst. E64, m424. Web of Science CSD CrossRef IUCr Journals Google Scholar
Liu, D.-S., Huang, G.-S., Huang, C.-C., Huang, X.-H., Chen, J.-Z. & You, X.-Z. (2009). Cryst. Growth Des. 9, 5117–5127. Web of Science CSD CrossRef CAS Google Scholar
Moncol, J., Mudra, M., Lönnecke, P., Hewitt, M., Valko, M., Morris, H., Svorec, J., Melnik, M., Mazur, M. & Koman, M. (2007). Inorg. Chim. Acta, 360, 3213–3225. Web of Science CSD CrossRef CAS Google Scholar
Rauko, P., Novotny, L., Dovinova, I., Hunakova, L., Szekeres, T. & Jayaram, H. N. (2001). Eur. J. Pharm. Sci. 12, 387–394. Web of Science CrossRef PubMed CAS Google Scholar
Rigaku (2002). CrystalClear. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rowland, J. M., Olmstead, M. & Mascharak, P. K. (2001). Inorg. Chem. 40, 2810–2817. Web of Science CSD CrossRef PubMed CAS Google Scholar
Rowland, J. M., Olmstead, M. & Mascharak, P. K. (2002). Inorg. Chim. Acta, 332, 37–40. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wang, Y.-B., Liu, D.-S., Pan, T.-H., Liang, Q., Huang, X.-H., Wu, S.-T. & Huang, C.-C. (2010). CrystEngComm, 12, 3886–3893. Web of Science CSD CrossRef CAS 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.