catena-Poly[[bis­(2-hydr­oxy-2-phenyl­acetato-κ2O1,O2)zinc(II)]-μ-1,2-di-4-pyridylethane-κ2N:N′]

Yu, S.M.; Shin, D.H.; Kim, P.-G.; Kim, C.; Kim, Y.

doi:10.1107/S1600536809030281

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 65| Part 9| September 2009| Pages m1045-m1046

doi:10.1107/S1600536809030281

Open

access

catena-Poly[[bis(2-hydroxy-2-phenylacetato-κ²O¹,O²)zinc(II)]-μ-1,2-di-4-pyridylethane-κ²N:N′]

Seung Man Yu,^a Dong Hoon Shin,^a Pan-Gi Kim,^b ^* Cheal Kim ^a and Youngmee Kim ^c ^*

^aDepartment of Fine Chemistry, and Eco-Products and Materials Education Center, Seoul National University of Technology, Seoul 139-743, Republic of Korea, ^bDepartment of Forest & Environmental Resources, Kyungpook National University, Sangju 742-711, Republic of Korea, and ^cDepartment of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Republic of Korea
^*Correspondence e-mail: chealkim@sunt.ac.kr, ymeekim@ewha.ac.kr

(Received 21 July 2009; accepted 30 July 2009; online 8 August 2009)

The title compound, [Zn(C₈H₆O₃)₂(C₁₂H₁₂N₂)]_n, consists of [Zn(Hopa)₂] (H₂opa = 2-hydroxy-2-phenylacetic acid or mandelic acid) units bridged by 1,2-di-4-pyridylethane (bpe) ligands, forming a polymeric chain developing parallel to the b axis. The bridging bpe ligand is arranged around a twofold axis passing through the middle of the ethane C—C bond. The geometry around the Zn^II ion is distorted octahedral, constructed by four O atoms from two Hopa⁻ ligands and two N atoms from two bridging bpe ligands. O—H⋯O hydrogen bonds link the chains, forming a three-dimensional network.

Related literature

Transition metal ions are the major cationic contributors to the inorganic composition of natural water and biological fluids, see: Daniele et al. (2008 ). For related structures, see: Balboa et al. (2008 ); Beghidja et al. (2005 ); Hao et al. (2009 ); Lee et al. (2008 ); Park et al. (2008 ); Shin et al. (2009 ); Wermester et al. (2007 ); Yu et al. (2008 ).

Experimental

Crystal data

[Zn(C₈H₆O₃)₂(C₁₂H₁₂N₂)]
M_r = 551.90
Hexagonal, P 6₁ 22
a = 11.1360 (6) Å
c = 33.110 (3) Å
V = 3555.9 (4) Å³
Z = 6
Mo Kα radiation
μ = 1.09 mm⁻¹
T = 293 K
0.10 × 0.05 × 0.05 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1997 ) T_min = 0.933, T_max = 0.944
17715 measured reflections
2347 independent reflections
2045 reflections with I > 2σ(I)
R_int = 0.077

Refinement

R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.068
S = 1.04
2347 reflections
168 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.21 e Å⁻³
Absolute structure: Flack (1983 ), 870 Friedel pairs
Flack parameter: −0.002 (16)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O13—H13O⋯O12ⁱ	0.85	1.77	2.619 (3)	173
Symmetry code: (i) $[x-y+1, x, z+{\script{1\over 6}}]$ .

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809030281/dn2478sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809030281/dn2478Isup2.hkl

checkCIF report

Comment top

A great attention has been paid to transition metal ions as the major cation contributors to the biologically active molecules such as amino acids, proteins, sugars, nucleotides etc (Daniele, et al., 2008). This interest has driven us to study on the interaction of the transition metal ions with fulvic acids or humic acids. As models to examine the interaction, therefore, we have previously used copper(II) and zinc(II) benzoates as building blocks and reported the structures of copper(II) and zinc(II) benzoates with quinoxaline, 6-methylquinoline, 3-methylquinoline, and di-2-pyridyl ketone(Lee et al., 2008; Yu et al., 2008; Park et al., 2008; Shin et al., 2009).

Mandelic acid (2-hydroxy-2-phenylacetic acid, H₂opa) is also one of the simplest bioactive molecules exhibiting a variety of coordinating and supramolecular interaction abilities (Balboa et al., 2008; Beghidja et al.,2005; Hao et al., 2009; Wermester et al., 2007). In order to study the interaction of the biologically active molecule mandelic acid with zinc(II) ion, in the present work, we have employed zinc(II) mandelate as a building block and 1,2-di-4-pyridylethane (bpe) as a ligand. We report herein the structure of new zinc(II) mandelate with 1,2-di-4-pyridylethane.

The crystal structure contains [Zn(Hopa)₂] units bridged by bpe ligands forming a polymeric chain developping parallel to the b axis. The bridging 1,2-di-4-pyridylethane (bpe) ligand is arranged around a two fold axis going through the middle of C26—C26ⁱⁱ bond (symmetry code: (ii) x, x-y+2, -z+1/6). The geometry around the Zn^II ion is distorted octahedral constructed by four oxygen atoms from two Hopa^- and two nitrogen atoms from two bridging bpe ligands (Fig. 1). The occurence of O-H···O hydrogen bonds links the chains to form a three dimensionnal network.

Related literature top

Transition metal ions are the major cationic contributors to the inorganic composition of natural water and biological fluids, see: Daniele et al. (2008). For related structures, see: Balboa et al. (2008); Beghidja et al. (2005); Hao et al. (2009); Lee et al. (2008); Park et al. (2008); Shin et al. (2009); Wermester et al. (2007); Yu et al. (2008).

Experimental top

38.0 mg (0.125 mmol) of Zn(NO₃)₂^.6H₂O and 38.4 mg (0.25 mmol) of 2-hydroxy-2-phenylacetic acid were dissolved in 4 ml water and carefully layered by 4 ml solution of a mixture of acetone, methanol and ethanol (2/2/2) of 1,2-di-4-pyridylethane ligand (46.0 mg, 0.25 mmol). Suitable crystals of the title compoundfor X-ray analysis were obtained in a few weeks.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

Fig. 1. View of compound I with the atom labeling scheme. Displacement ellipsoids are drawn at the 30° probability level. H atoms have been omitted for clarity. [Symmetry codes: (i) x, x-y+1, -z+1/6; (ii) x, x-y+2, -z+1/6].

catena-Poly[[bis(2-hydroxy-2-phenylacetato- κ²O¹,O²)zinc(II)]- µ-1,2-di-4-pyridylethane-κ²N:N'] top

Crystal data top

[Zn(C₈H₆O₃)₂(C₁₂H₁₂N₂)]	D_x = 1.546 Mg m⁻³
M_r = 551.90	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6₁22	Cell parameters from 1751 reflections
Hall symbol: P 61 2 (0 0 -1)	θ = 2.2–18.9°
a = 11.1360 (6) Å	µ = 1.09 mm⁻¹
c = 33.110 (3) Å	T = 293 K
V = 3555.9 (4) Å³	Rod, colorless
Z = 6	0.10 × 0.05 × 0.05 mm
F(000) = 1716

Data collection top

Bruker SMART CCD diffractometer	2347 independent reflections
Radiation source: fine-focus sealed tube	2045 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.077
ϕ and ω scans	θ_max = 26.0°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −13→13
T_min = 0.933, T_max = 0.944	k = −11→13
17715 measured reflections	l = −40→28

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)] = 0.032	H-atom parameters constrained
wR(F²) = 0.068	w = 1/[σ²(F_o²) + (0.016P)² + 1.0575P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
2347 reflections	Δρ_max = 0.22 e Å⁻³
168 parameters	Δρ_min = −0.21 e Å⁻³
1 restraint	Absolute structure: Flack (1983), 870 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.002 (16)

Crystal data top

[Zn(C₈H₆O₃)₂(C₁₂H₁₂N₂)]	Z = 6
M_r = 551.90	Mo Kα radiation
Hexagonal, P6₁22	µ = 1.09 mm⁻¹
a = 11.1360 (6) Å	T = 293 K
c = 33.110 (3) Å	0.10 × 0.05 × 0.05 mm
V = 3555.9 (4) Å³

Data collection top

Bruker SMART CCD diffractometer	2347 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1997)	2045 reflections with I > 2σ(I)
T_min = 0.933, T_max = 0.944	R_int = 0.077
17715 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	H-atom parameters constrained
wR(F²) = 0.068	Δρ_max = 0.22 e Å⁻³
S = 1.04	Δρ_min = −0.21 e Å⁻³
2347 reflections	Absolute structure: Flack (1983), 870 Friedel pairs
168 parameters	Absolute structure parameter: −0.002 (16)
1 restraint

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 > 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	0.73603 (4)	0.86802 (2)	0.0833	0.01944 (12)
O11	0.76202 (18)	0.84579 (18)	0.02239 (5)	0.0216 (4)
O12	0.89644 (18)	0.82448 (18)	−0.02384 (5)	0.0245 (5)
O13	0.89365 (17)	0.81243 (17)	0.08319 (5)	0.0233 (4)
H13O	0.9568	0.8433	0.1013	0.035*
N21	0.5928 (2)	0.9386 (2)	0.07376 (7)	0.0223 (5)
C11	0.8619 (3)	0.8302 (2)	0.01183 (8)	0.0191 (6)
C12	0.9540 (3)	0.8194 (3)	0.04470 (8)	0.0179 (6)
H12	1.0448	0.9043	0.0438	0.022*
C13	0.9761 (3)	0.6975 (3)	0.03869 (8)	0.0201 (6)
C14	1.1078 (3)	0.7159 (3)	0.03588 (9)	0.0284 (7)
H14	1.1839	0.8052	0.0368	0.034*
C15	1.1293 (4)	0.6038 (4)	0.03167 (10)	0.0394 (8)
H15	1.2189	0.6185	0.0295	0.047*
C16	1.0181 (4)	0.4716 (4)	0.03078 (10)	0.0423 (9)
H16	1.0316	0.3960	0.0283	0.051*
C17	0.8862 (4)	0.4520 (3)	0.03359 (9)	0.0382 (8)
H17	0.8105	0.3624	0.0328	0.046*
C18	0.8639 (3)	0.5636 (3)	0.03754 (8)	0.0280 (6)
H18	0.7741	0.5486	0.0394	0.034*
C21	0.6235 (3)	1.0429 (3)	0.04786 (9)	0.0310 (8)
H21	0.7018	1.0742	0.0317	0.037*
C22	0.5445 (3)	1.1057 (3)	0.04412 (10)	0.0357 (8)
H22	0.5682	1.1757	0.0252	0.043*
C23	0.4294 (3)	1.0642 (3)	0.06862 (10)	0.0289 (7)
C24	0.4001 (3)	0.9599 (3)	0.09618 (9)	0.0288 (7)
H24	0.3251	0.9299	0.1136	0.035*
C25	0.4832 (3)	0.9009 (3)	0.09751 (8)	0.0252 (6)
H25	0.4613	0.8304	0.1161	0.030*
C26	0.3364 (3)	1.1263 (3)	0.06523 (12)	0.0520 (11)
H26A	0.2422	1.0517	0.0607	0.062*
H26B	0.3641	1.1857	0.0416	0.062*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Zn1	0.0209 (2)	0.01972 (17)	0.0181 (2)	0.01044 (12)	0.000	−0.00108 (18)
O11	0.0248 (10)	0.0247 (10)	0.0185 (10)	0.0148 (8)	−0.0010 (8)	0.0008 (8)
O12	0.0311 (12)	0.0325 (11)	0.0154 (10)	0.0200 (9)	0.0007 (9)	0.0017 (8)
O13	0.0270 (10)	0.0352 (10)	0.0135 (9)	0.0198 (9)	−0.0050 (9)	−0.0048 (8)
N21	0.0218 (12)	0.0224 (12)	0.0213 (14)	0.0101 (10)	0.0011 (10)	0.0006 (10)
C11	0.0231 (13)	0.0141 (14)	0.0176 (15)	0.0074 (12)	−0.0024 (13)	−0.0004 (11)
C12	0.0190 (13)	0.0189 (13)	0.0142 (14)	0.0083 (10)	−0.0012 (11)	−0.0025 (11)
C13	0.0274 (15)	0.0231 (15)	0.0113 (13)	0.0137 (12)	−0.0034 (11)	0.0004 (12)
C14	0.0297 (17)	0.0309 (16)	0.0296 (18)	0.0189 (14)	−0.0055 (13)	−0.0065 (14)
C15	0.048 (2)	0.057 (2)	0.0319 (19)	0.040 (2)	−0.0055 (17)	−0.0054 (17)
C16	0.080 (3)	0.049 (2)	0.0260 (18)	0.053 (2)	−0.0044 (18)	−0.0044 (16)
C17	0.062 (2)	0.0242 (17)	0.0226 (17)	0.0172 (17)	−0.0001 (16)	−0.0020 (14)
C18	0.0350 (16)	0.0237 (16)	0.0215 (15)	0.0117 (14)	−0.0015 (14)	−0.0003 (13)
C21	0.0241 (16)	0.0359 (18)	0.0286 (18)	0.0118 (14)	0.0005 (13)	0.0089 (14)
C22	0.0329 (18)	0.0310 (18)	0.0393 (19)	0.0131 (16)	−0.0083 (15)	0.0094 (14)
C23	0.0298 (17)	0.0265 (15)	0.0344 (19)	0.0172 (14)	−0.0179 (14)	−0.0153 (14)
C24	0.0275 (17)	0.0359 (18)	0.0293 (17)	0.0206 (14)	0.0010 (13)	−0.0039 (14)
C25	0.0306 (16)	0.0239 (16)	0.0219 (15)	0.0143 (12)	0.0033 (13)	0.0018 (12)
C26	0.039 (2)	0.0319 (17)	0.093 (3)	0.0242 (16)	−0.0356 (19)	−0.0234 (19)

Geometric parameters (Å, º) top

Zn1—O11	2.0707 (17)	C15—C16	1.371 (5)
Zn1—O11ⁱ	2.0707 (17)	C15—H15	0.9300
Zn1—N21	2.125 (2)	C16—C17	1.376 (5)
Zn1—N21ⁱ	2.125 (2)	C16—H16	0.9300
Zn1—O13ⁱ	2.1332 (17)	C17—C18	1.390 (4)
Zn1—O13	2.1332 (17)	C17—H17	0.9300
O11—C11	1.258 (3)	C18—H18	0.9300
O12—C11	1.254 (3)	C21—C22	1.376 (4)
O13—C12	1.425 (3)	C21—H21	0.9300
O13—H13O	0.8543	C22—C23	1.386 (4)
N21—C25	1.332 (3)	C22—H22	0.9300
N21—C21	1.344 (3)	C23—C24	1.381 (4)
C11—C12	1.541 (4)	C23—C26	1.511 (4)
C12—C13	1.509 (4)	C24—C25	1.378 (4)
C12—H12	0.9800	C24—H24	0.9300
C13—C14	1.379 (4)	C25—H25	0.9300
C13—C18	1.387 (4)	C26—C26ⁱⁱ	1.519 (7)
C14—C15	1.390 (4)	C26—H26A	0.9700
C14—H14	0.9300	C26—H26B	0.9700

O11—Zn1—O11ⁱ	166.10 (10)	C13—C14—H14	119.3
O11—Zn1—N21	94.27 (8)	C15—C14—H14	119.3
O11ⁱ—Zn1—N21	94.75 (8)	C16—C15—C14	119.8 (3)
O11—Zn1—N21ⁱ	94.75 (8)	C16—C15—H15	120.1
O11ⁱ—Zn1—N21ⁱ	94.27 (8)	C14—C15—H15	120.1
N21—Zn1—N21ⁱ	98.92 (11)	C15—C16—C17	119.3 (3)
O11—Zn1—O13ⁱ	92.80 (7)	C15—C16—H16	120.4
O11ⁱ—Zn1—O13ⁱ	77.21 (7)	C17—C16—H16	120.4
N21—Zn1—O13ⁱ	86.60 (7)	C16—C17—C18	121.2 (3)
N21ⁱ—Zn1—O13ⁱ	170.28 (8)	C16—C17—H17	119.4
O11—Zn1—O13	77.21 (7)	C18—C17—H17	119.4
O11ⁱ—Zn1—O13	92.80 (7)	C13—C18—C17	119.8 (3)
N21—Zn1—O13	170.28 (8)	C13—C18—H18	120.1
N21ⁱ—Zn1—O13	86.60 (7)	C17—C18—H18	120.1
O13ⁱ—Zn1—O13	89.11 (9)	N21—C21—C22	123.1 (3)
C11—O11—Zn1	118.26 (16)	N21—C21—H21	118.5
C12—O13—Zn1	114.85 (15)	C22—C21—H21	118.5
C12—O13—H13O	109.5	C21—C22—C23	119.8 (3)
Zn1—O13—H13O	120.8	C21—C22—H22	120.1
C25—N21—C21	116.5 (2)	C23—C22—H22	120.1
C25—N21—Zn1	122.35 (18)	C24—C23—C22	117.2 (3)
C21—N21—Zn1	120.11 (19)	C24—C23—C26	120.4 (3)
O12—C11—O11	125.7 (3)	C22—C23—C26	122.4 (3)
O12—C11—C12	115.4 (2)	C25—C24—C23	119.3 (3)
O11—C11—C12	118.9 (2)	C25—C24—H24	120.4
O13—C12—C13	110.7 (2)	C23—C24—H24	120.4
O13—C12—C11	108.8 (2)	N21—C25—C24	124.0 (3)
C13—C12—C11	113.0 (2)	N21—C25—H25	118.0
O13—C12—H12	108.1	C24—C25—H25	118.0
C13—C12—H12	108.1	C23—C26—C26ⁱⁱ	115.7 (3)
C11—C12—H12	108.1	C23—C26—H26A	108.4
C14—C13—C18	118.5 (3)	C26ⁱⁱ—C26—H26A	108.4
C14—C13—C12	121.0 (3)	C23—C26—H26B	108.4
C18—C13—C12	120.4 (2)	C26ⁱⁱ—C26—H26B	108.4
C13—C14—C15	121.4 (3)	H26A—C26—H26B	107.4

Symmetry codes: (i) x, x−y+1, −z+1/6; (ii) x, x−y+2, −z+1/6.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O13—H13O···O12ⁱⁱⁱ	0.85	1.77	2.619 (3)	173

Symmetry code: (iii) x−y+1, x, z+1/6.

Experimental details

Crystal data
Chemical formula	[Zn(C₈H₆O₃)₂(C₁₂H₁₂N₂)]
M_r	551.90
Crystal system, space group	Hexagonal, P6₁22
Temperature (K)	293
a, c (Å)	11.1360 (6), 33.110 (3)
V (Å³)	3555.9 (4)
Z	6
Radiation type	Mo Kα
µ (mm⁻¹)	1.09
Crystal size (mm)	0.10 × 0.05 × 0.05

Data collection
Diffractometer	Bruker SMART CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 1997)
T_min, T_max	0.933, 0.944
No. of measured, independent and observed [I > 2σ(I)] reflections	17715, 2347, 2045
R_int	0.077
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.068, 1.04
No. of reflections	2347
No. of parameters	168
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.21
Absolute structure	Flack (1983), 870 Friedel pairs
Absolute structure parameter	−0.002 (16)

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O13—H13O···O12ⁱ	0.85	1.77	2.619 (3)	173.3

Symmetry code: (i) x−y+1, x, z+1/6.

Acknowledgements

Financial support from the Korea Ministry of the Environment `ET-Human Resource Development Project' and the Cooperative Research Program for Agricultural Science & Technology Development (20070301–036-019–02) is gratefully acknowledged.

References

Balboa, S., Carballo, R., Castineiras, A., Gonzalez-Perez, J. M. & Niclos-Gutierrez, J. (2008). Polyhedron, 27, 2921–2930. Web of Science CSD CrossRef CAS Google Scholar
Beghidja, A., Hallynck, S., Welter, R. & Rabu, P. (2005). Eur. J. Inorg. Chem. pp. 662–669. Web of Science CSD CrossRef Google Scholar
Bruker (1997). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Daniele, P. G., Foti, C., Gianguzza, A., Prenesti, E. & Sammartano, S. (2008). Coord. Chem. Rev. 252, 1093–1107. Web of Science CrossRef CAS Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Hao, H.-Q., Liu, W.-T., Tan, W., Lin, Z.-J. & Tong, M.-L. (2009). CrystEngComm, 11, 967–971. Web of Science CSD CrossRef CAS Google Scholar
Lee, E. Y., Park, B. K., Kim, C., Kim, S.-J. & Kim, Y. (2008). Acta Cryst. E64, m286. Web of Science CSD CrossRef IUCr Journals Google Scholar
Park, B. K., Jang, K.-H., Kim, P.-G., Kim, C. & Kim, Y. (2008). Acta Cryst. E64, m1141. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Shin, D. H., Han, S.-H., Kim, P.-G., Kim, C. & Kim, Y. (2009). Acta Cryst. E65, m658–m659. Web of Science CSD CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wermester, N., Aubin, E., Pauchet, M., Coste, S. & Coquerel, G. (2007). Tetrahedron Asymmetry, 18, 821–831. Web of Science CSD CrossRef CAS Google Scholar
Yu, S. M., Park, C.-H., Kim, P.-G., Kim, C. & Kim, Y. (2008). Acta Cryst. E64, m881–m882. Web of Science CSD CrossRef 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.