2,2′-[1,1′-(Propane-1,3-diyldioxy­dinitrilo)diethyl­idyne]diphenol

Dong, W.-K.; He, X.-N.; Zhong, J.-K.; Chen, X.; Yu, T.-Z.

doi:10.1107/S1600536808012701

organic compounds

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Volume 64| Part 6| June 2008| Page o1098

doi:10.1107/S1600536808012701

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2,2′-[1,1′-(Propane-1,3-diyldioxydinitrilo)diethylidyne]diphenol

Wen-Kui Dong,^a ^* Xue-Ni He,^a Jin-Kui Zhong,^a Xiao Chen ^a and Tian-Zhi Yu ^b

^aSchool of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, People's Republic of China, and ^bKey Laboratory of Opto-Electronic Technology and Intelligent Control, Ministry of Education, Lanzhou 730070, People's Republic of China
^*Correspondence e-mail: dongwk@mail.lzjtu.cn

(Received 21 March 2008; accepted 30 April 2008; online 17 May 2008)

The title compound, C₁₉H₂₂N₂O₄, was synthesized by the reaction of 2′-hydroxyacetophenone with 1,3-bis(aminooxy)propane in ethanol. Intramolecular O—H⋯N and weak C—H⋯O hydrogen bonds stabilize the three-dimensional structure. A twofold rotation axis passes through the molecule.

Related literature

For related literature, see: Atkins et al. (1985 ); Atwood (1997 ); Costes et al. (2000 ); Dong & Feng (2006 ); Dong et al. (2006a ,b , 2007a ,b ,c ,d ); Duan et al. (2007 ); Katsuki (1995 ); Lacroix (2001 ); Venkataramanan et al. (2005 ); Yu et al. (2008 ); Zhang et al. (2007 ).

Experimental

Crystal data

C₁₉H₂₂N₂O₄
M_r = 342.39
Orthorhombic, P b a 2
a = 7.4595 (15) Å
b = 25.459 (2) Å
c = 4.5938 (8) Å
V = 872.4 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 (2) K
0.40 × 0.19 × 0.17 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.964, T_max = 0.985
3761 measured reflections
880 independent reflections
601 reflections with I > 2σ(I)
R_int = 0.080

Refinement

R[F² > 2σ(F²)] = 0.052
wR(F²) = 0.162
S = 1.12
880 reflections
114 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯N1	0.82	1.85	2.570 (5)	146
C3—H3A⋯O1	0.96	2.17	2.603 (6)	106

Data collection: SMART (Siemens, 1996 ); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; 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: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808012701/hg2386sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808012701/hg2386Isup2.hkl

checkCIF report

Comment top

Salen-type compounds have been intensively used as versatile chelating ligands in the formation of transition metal complexes (Yu et al., 2008). Some of them or their metal complexes are used in various organic reaction processes as catalysts (Venkataramanan et al., 2005), models of reaction centers of metalloenzymes (Katsuki et al., 1995), have fascinating magnetic properties (Costes et al., 2000) and are nonlinear optical materials (Lacroix et al., 2001). They can also be used as biological models in understanding the structure of biomolecules and biological processes (Atkins et al., 1985, Atwood et al., 1997). Most of their important features of these compounds are their preparative accessibility, diversity and structural variability, which make them more attractive.

In recent years, we have been very much interested in the synthesis and study of salen-type bisoxime derivatives, such as 2,2'-[(1,4-butylene)dioxybis(nitrilomethylidyne)]dinaphthol (Dong et al., 2006a), 4,4'-dibromo-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol (Dong & Feng, 2006), 4,4'-dibromo-2,2'-[(1,3-propylene) dioxybis(nitrilomethylidyne)]diphenol (Dong et al., 2006b), 2,2'-[(1,4-butylene)dioxybis(nitrilomethylidyne)]diphenol (Dong et al., 2007a), 4,4'-dichloro-2,2'-[(1,4-butylene)dioxybis(nitrilomethylidyne)]diphenol (Dong et al., 2007b), 4,4'6,6'-tetra(tert-butyl)-2,2'-[(1,4-butylene)dioxybis (nitrilomethylidyne)]diphenol (Dong et al., 2007c), 2,2'-[(1,4-butylene)dioxybis(nitriloethylidyne)]diphenol (Dong et al., 2007d), 2,2'-[(propane-1,3-diyldioxy)bis(nitrilomethylidyne)]diphenol (Duan et al., 2007), and 5,5'-bis(diethylamino)-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol (Zhang et al., 2007). In this paper, a novel bisoxime ligand, 2,2'-[(propane-1,3-diyldioxy)bis(nitriloethylidyne)]diphenol (I) was designed and synthesized, and shown in Fig. 1.

The single-crystal structure of (I) is built up by discrete C₁₉H₂₂N₂O₄ molecules (Fig. 1), in which all bond lengths are in normal ranges. There is a crystallographic twofold rotation axis passing through the middle point (symmetry code: -x, -y, z) of the C—C—C unit. The molecule adopts a trans conguration in which two phenoldoxime moieties adopts an extended form, where the oxime, methyl groups and phenolic alcohols lie in trans positions relative to the C2 atom in the N—-O—CH₂—CH₂—CH₂—O—N linkage, which is similar to what is observed in our previously reported salen-type bisoxime of 2,2'-[(propane-1,3-diyldioxy)bis(nitrilomethylidyne)]diphenol (Duan et al., 2007). There is an intramolecular O—H···N hydrogen bond between the N1 atom and the hydroxy proton (Table 1) generating a six membered ring, which with weak C—H···O intermolecular hydrogen bonds, stabilizes the three-dimensional structure of (I).

Related literature top

For related literature, see: Atkins et al. (1985); Atwood (1997); Costes et al. (2000); Dong & Feng (2006); Dong et al. (2006a,b, 2007a,b,c,d); Duan et al. (2007); Katsuki (1995); Lacroix (2001); Venkataramanan et al. (2005); Yu et al. (2008); Zhang et al. (2007).

Experimental top

2,2'-[(Propane-1,3-diyldioxy)bis(nitriloethylidyne)]diphenol was synthesized according to an analogous method reported earlier (Dong et al., 2007d). To an ethanol solution (5 ml) of 2'-hydroxyacetophenone (280.9 mg, 2.01 mmol) was added an ethanol (3 ml) solution of 1,3-bis(aminooxy)propane (105.5 mg, 1.00 mmol). The mixture solution was stirred at 328 K for 3 h. After cool to room temperature, the precipitate was formed, which was filtered, and washed successively with ethanol and ethanol/hexane (1:4), respectively. The product was dried under vacuum and to yield 64.90 mg of the title compound. Yield, 19.1%. mp. 363–363.5 K. Anal. Calc. for C₁₉H₂₂N₂O₄: C, 66.65; H, 6.48; N, 8.18. Found: C, 66.76; H, 6.39; N, 7.97. Colorless needle-shaped single crystals suitable for X-ray diffraction studies were obtained after three months by slow evaporation from an ethanol solution (10 ml) of 2,2'-[(propane-1,3-diyldioxy)bis(nitriloethylidyne)]diphenol.

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); 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: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. Molecule structure of (I) possessing a crystallographic twofold rotation axis passing through the middle point of the C—C—C unit (symmetry code: -x+1, -y, z), Displacement ellipsoids for non-hydrogen atoms are drawn at the 30% probability level.

2,2'-[1,1'-(Propane-1,3-diyldioxydinitrilo)diethylidyne]diphenol top

Crystal data top

C₁₉H₂₂N₂O₄	F(000) = 364
M_r = 342.39	D_x = 1.303 Mg m⁻³
Orthorhombic, Pba2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 -2ab	Cell parameters from 1047 reflections
a = 7.4595 (15) Å	θ = 2.4–22.9°
b = 25.459 (2) Å	µ = 0.09 mm⁻¹
c = 4.5938 (8) Å	T = 298 K
V = 872.4 (2) Å³	Needle-shaped, colorless
Z = 2	0.40 × 0.19 × 0.17 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	880 independent reflections
Radiation source: fine-focus sealed tube	601 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.080
ϕ and ω scans	θ_max = 25.0°, θ_min = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→4
T_min = 0.964, T_max = 0.985	k = −30→28
3761 measured reflections	l = −5→5

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)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.162	H-atom parameters constrained
S = 1.12	w = 1/[σ²(F_o²) + (0.09P)²] where P = (F_o² + 2F_c²)/3
880 reflections	(Δ/σ)_max < 0.001
114 parameters	Δρ_max = 0.18 e Å⁻³
1 restraint	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₁₉H₂₂N₂O₄	V = 872.4 (2) Å³
M_r = 342.39	Z = 2
Orthorhombic, Pba2	Mo Kα radiation
a = 7.4595 (15) Å	µ = 0.09 mm⁻¹
b = 25.459 (2) Å	T = 298 K
c = 4.5938 (8) Å	0.40 × 0.19 × 0.17 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	880 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	601 reflections with I > 2σ(I)
T_min = 0.964, T_max = 0.985	R_int = 0.080
3761 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.052	1 restraint
wR(F²) = 0.162	H-atom parameters constrained
S = 1.12	Δρ_max = 0.18 e Å⁻³
880 reflections	Δρ_min = −0.20 e Å⁻³
114 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	Occ. (<1)
N1	0.7665 (5)	0.07883 (13)	0.2794 (9)	0.0424 (10)
O1	0.6235 (4)	0.06405 (11)	0.0997 (8)	0.0497 (10)
O2	1.0675 (4)	0.06514 (11)	0.5410 (10)	0.0613 (12)
H2	0.9857	0.0579	0.4284	0.092*
C1	0.6621 (6)	0.01443 (16)	−0.0329 (12)	0.0447 (13)
H1A	0.6845	−0.0120	0.1148	0.054*
H1B	0.7671	0.0171	−0.1564	0.054*
C2	0.5000	0.0000	−0.2107 (16)	0.0479 (18)
H2A	0.5305	−0.0294	−0.3353	0.058*	0.50
H2B	0.4695	0.0294	−0.3353	0.058*	0.50
C3	0.5696 (7)	0.15361 (18)	0.3585 (17)	0.0660 (17)
H3A	0.5088	0.1406	0.1891	0.099*
H3B	0.5989	0.1900	0.3308	0.099*
H3C	0.4931	0.1500	0.5254	0.099*
C4	0.7390 (6)	0.12265 (17)	0.4060 (10)	0.0406 (12)
C5	0.8802 (6)	0.14197 (16)	0.5999 (11)	0.0380 (11)
C6	1.0350 (6)	0.11254 (15)	0.6663 (11)	0.0396 (12)
C7	1.1585 (6)	0.1310 (2)	0.8622 (13)	0.0540 (15)
H7	1.2586	0.1107	0.9065	0.065*
C8	1.1363 (6)	0.1787 (2)	0.9934 (16)	0.0582 (15)
H8	1.2207	0.1908	1.1263	0.070*
C9	0.9884 (8)	0.2086 (2)	0.9277 (16)	0.0649 (18)
H9	0.9733	0.2414	1.0135	0.078*
C10	0.8645 (7)	0.19013 (18)	0.7369 (13)	0.0521 (15)
H10	0.7646	0.2108	0.6966	0.063*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.038 (2)	0.047 (2)	0.043 (2)	−0.0020 (17)	−0.005 (2)	0.002 (2)
O1	0.0458 (18)	0.0516 (19)	0.052 (2)	−0.0039 (14)	−0.0123 (19)	−0.0063 (18)
O2	0.053 (2)	0.054 (2)	0.077 (3)	0.0138 (15)	−0.018 (2)	−0.0045 (19)
C1	0.048 (3)	0.041 (2)	0.045 (3)	−0.004 (2)	0.005 (3)	−0.001 (2)
C2	0.068 (5)	0.046 (3)	0.030 (4)	−0.007 (3)	0.000	0.000
C3	0.051 (3)	0.060 (3)	0.087 (5)	0.009 (2)	−0.021 (4)	−0.015 (3)
C4	0.038 (2)	0.042 (2)	0.042 (3)	0.000 (2)	−0.005 (2)	0.004 (2)
C5	0.035 (2)	0.045 (2)	0.034 (3)	−0.001 (2)	−0.001 (2)	0.004 (2)
C6	0.035 (2)	0.042 (2)	0.042 (3)	−0.002 (2)	−0.002 (2)	0.010 (2)
C7	0.036 (3)	0.066 (3)	0.060 (4)	0.002 (2)	−0.015 (3)	0.009 (3)
C8	0.046 (3)	0.072 (3)	0.057 (4)	−0.015 (3)	−0.011 (3)	−0.001 (3)
C9	0.057 (3)	0.056 (3)	0.082 (5)	−0.003 (3)	−0.017 (4)	−0.016 (3)
C10	0.043 (3)	0.056 (3)	0.057 (4)	0.006 (2)	−0.004 (3)	0.003 (3)

Geometric parameters (Å, º) top

N1—C4	1.275 (5)	C3—H3B	0.9600
N1—O1	1.400 (5)	C3—H3C	0.9600
O1—C1	1.432 (5)	C4—C5	1.464 (6)
O2—C6	1.359 (5)	C5—C10	1.383 (6)
O2—H2	0.8200	C5—C6	1.410 (6)
C1—C2	1.505 (6)	C6—C7	1.370 (7)
C1—H1A	0.9700	C7—C8	1.366 (7)
C1—H1B	0.9700	C7—H7	0.9300
C2—C1ⁱ	1.505 (6)	C8—C9	1.374 (7)
C2—H2A	0.9700	C8—H8	0.9300
C2—H2B	0.9700	C9—C10	1.358 (8)
C3—C4	1.505 (6)	C9—H9	0.9300
C3—H3A	0.9600	C10—H10	0.9300

C4—N1—O1	112.4 (3)	N1—C4—C5	117.1 (4)
N1—O1—C1	109.5 (3)	N1—C4—C3	121.8 (4)
C6—O2—H2	109.5	C5—C4—C3	121.1 (4)
O1—C1—C2	106.5 (3)	C10—C5—C6	116.2 (4)
O1—C1—H1A	110.4	C10—C5—C4	120.9 (4)
C2—C1—H1A	110.4	C6—C5—C4	122.8 (4)
O1—C1—H1B	110.4	O2—C6—C7	117.6 (4)
C2—C1—H1B	110.4	O2—C6—C5	121.7 (4)
H1A—C1—H1B	108.6	C7—C6—C5	120.7 (4)
C1—C2—C1ⁱ	114.3 (6)	C8—C7—C6	120.8 (5)
C1—C2—H2A	108.7	C8—C7—H7	119.6
C1ⁱ—C2—H2A	108.7	C6—C7—H7	119.6
C1—C2—H2B	108.7	C7—C8—C9	119.6 (5)
C1ⁱ—C2—H2B	108.7	C7—C8—H8	120.2
H2A—C2—H2B	107.6	C9—C8—H8	120.2
C4—C3—H3A	109.5	C10—C9—C8	119.7 (5)
C4—C3—H3B	109.5	C10—C9—H9	120.1
H3A—C3—H3B	109.5	C8—C9—H9	120.1
C4—C3—H3C	109.5	C9—C10—C5	122.9 (5)
H3A—C3—H3C	109.5	C9—C10—H10	118.5
H3B—C3—H3C	109.5	C5—C10—H10	118.5

C4—N1—O1—C1	−179.4 (4)	C4—C5—C6—O2	3.6 (7)
N1—O1—C1—C2	177.5 (4)	C10—C5—C6—C7	1.7 (7)
O1—C1—C2—C1ⁱ	−70.3 (3)	C4—C5—C6—C7	−176.2 (4)
O1—N1—C4—C5	180.0 (3)	O2—C6—C7—C8	178.9 (5)
O1—N1—C4—C3	−0.3 (7)	C5—C6—C7—C8	−1.3 (8)
N1—C4—C5—C10	177.4 (5)	C6—C7—C8—C9	−0.1 (9)
C3—C4—C5—C10	−2.3 (7)	C7—C8—C9—C10	1.1 (10)
N1—C4—C5—C6	−4.9 (6)	C8—C9—C10—C5	−0.7 (9)
C3—C4—C5—C6	175.4 (5)	C6—C5—C10—C9	−0.7 (8)
C10—C5—C6—O2	−178.6 (4)	C4—C5—C10—C9	177.2 (5)

Symmetry code: (i) −x+1, −y, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···N1	0.82	1.85	2.570 (5)	146
C3—H3A···O1	0.96	2.17	2.603 (6)	106

Experimental details

Crystal data
Chemical formula	C₁₉H₂₂N₂O₄
M_r	342.39
Crystal system, space group	Orthorhombic, Pba2
Temperature (K)	298
a, b, c (Å)	7.4595 (15), 25.459 (2), 4.5938 (8)
V (Å³)	872.4 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.40 × 0.19 × 0.17

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.964, 0.985
No. of measured, independent and observed [I > 2σ(I)] reflections	3761, 880, 601
R_int	0.080
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.052, 0.162, 1.12
No. of reflections	880
No. of parameters	114
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.20

Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), 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
O2—H2···N1	0.8200	1.8500	2.570 (5)	146.00
C3—H3A···O1	0.9600	2.1700	2.603 (6)	106.00

Acknowledgements

Support of this work by the Foundation of the Education Department of Gansu Province (No. 0604–01) and the `Qing Lan' Talent Engineering Funds of Lanzhou Jiaotong University (No. QL-03–01 A) is gratefully acknowledged.

References

Atkins, R., Brewer, G., Kokot, E., Mockler, G. M. & Sinn, E. (1985). Inorg. Chem. 24, 127–134. CSD CrossRef CAS Web of Science Google Scholar
Atwood, D. A. (1997). Coord. Chem. Rev. 165, 267–296. CrossRef CAS Google Scholar
Costes, J.-P., Dahan, F. & Dupuis, A. (2000). Inorg. Chem. 39, 165–168. Web of Science CSD CrossRef PubMed CAS Google Scholar
Dong, W. K., Duan, J. G., Dong, C. M., Ren, Z. L. & Shi, J. Y. (2007a). Z. Kristallogr. New Cryst. Struct. 222, 327–328. CAS Google Scholar
Dong, W. K., Duan, J. G., Wu, H. L., Shi, J. Y. & Yu, T. Z. (2006a). Z. Kristallogr. New Cryst. Struct. 221, 555–556. CAS Google Scholar
Dong, W.-K. & Feng, J.-H. (2006). Acta Cryst. E62, o3577–o3578. Web of Science CSD CrossRef IUCr Journals Google Scholar
Dong, W. K., Feng, J. H. & Yang, X. Q. (2006b). Z. Kristallogr. New Cryst. Struct. 221, 447–448. CAS Google Scholar
Dong, W. K., Feng, J. H. & Yang, X. Q. (2007c). Z. Kristallogr. New Cryst. Struct. 222, 50–52. CAS Google Scholar
Dong, W. K., He, X. N., Dong, C. M., Wang, L., Zhong, J. K., Chen, X. & Yu, T. Z. (2007d). Z. Kristallogr. New Cryst. Struct. 222, 289–290. CAS Google Scholar
Dong, W. K., Shi, J. Y., Sun, Y. X., Wang, L., Duan, J. G., Zhong, J. K. & Xu, L. (2007b). Anal. Sci. 23, x167–x168. CAS Google Scholar
Duan, J.-G., Dong, C.-M., Shi, J.-Y., Wu, L. & Dong, W.-K. (2007). Acta Cryst. E63, o2704–o2705. Web of Science CSD CrossRef IUCr Journals Google Scholar
Katsuki, T. (1995). Coord. Chem. Rev. 140, 189–214. CrossRef CAS Web of Science Google Scholar
Lacroix, P. G. (2001). Eur. J. Inorg. Chem. pp. 339–348. CrossRef Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Siemens (1996). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar
Venkataramanan, N. S., Kuppuraj, G. & Rajagopal, S. (2005). Coord. Chem. Rev. 249, 1249–1268. Web of Science CrossRef CAS Google Scholar
Yu, T. Z., Zhang, K., Zhao, Y., Yang, C. H., Zhang, H., Qian, L., Fan, D. W., Dong, W. K., Chen, L. L. & Qiu, Y. Q. (2008). Inorg. Chim. Acta, 361, 233–240. Web of Science CSD CrossRef CAS Google Scholar
Zhang, Y.-P., Chen, X., Shi, J.-Y., Xu, L. & Dong, W.-K. (2007). Acta Cryst. E63, o3852. Web of Science CSD CrossRef IUCr Journals Google Scholar