supplementary materials


om2255 scheme

Acta Cryst. (2008). E64, m1171-m1172    [ doi:10.1107/S160053680802583X ]

Bis([mu]-biphenyl-2,2'-dicarboxylato)bis[(2,2'-bipyridine)copper(II)]

H.-X. Guo, M. Liang, B. Lin, Q.-H. Wang and X.-Z. Li

Abstract top

The title compound, [Cu2(C14H8O4)2(C10H8N2)2], is a centrosymmetric binuclear copper(II) complex, with a Cu...Cu separation of 6.136 (16) Å. The Cu atom displays a cis-CuN2O2 square-planar geometry, although two long (> 2.43 Å) Cu...O contacts complete a distorted cis-CuN2O4 octahedron. Extensive C-H...O hydrogen bonds link the molecules into a three-dimensional network.

Comment top

Design and assembly of metal-involved supramolecular architectures are currently of great interest in the field of supramolecular chemistry and crystal engineering because they can provide novel topology and functional materials (Yaghi et al.,2003; Rao et al.,2004). During the past decades, extensive efforts have been focused on the design and assembly of such kinds of supramolecular architectures (Huang et al.,2004; Zhang et al., 2004). By precisely selecting the modular building unit, chemists now have successfully synthesized a great variety of one-dimensional, two-dimensional, and three-dimensional supramolecular architectures (Bu et al., 2004; Ma et al., 2003; Yang et al., 2002; Long et al., 2001). Binuclear copper(II) complexes have been intensely investigated owing to their potential application as magnetic materials and catalysts (Zhu et al., 2001).In this work, we employed H2dpa (dpa = diphenyl-2,2'-dicarboxylato dianion) and 2,2'-bipyridine(bipy) ligands for producing a binuclear complex, [Cu2(C14H8O4)2(C10H8N2)2].

The compound contains a centrosymmetric binuclear complex. The copper(II) atom in the title compound adopts a distorted square geometry (Table 1, Fig. 1). The bipy ligand shows its classical bidentate coordination mode, with a similar Cu—N bond length to that the related complex [Cu2(C14H8O4)2(C10H8N2)2].4H2O (He et al., 2007). The dpa ligand adopts a µ-bridged coordination and the dihedral angle between its aromatic rings is 78.27°. As well as the short Cu—O bonds, two long Cu—O (Cu(1)—O(2): 2.434 (44) Å; Cu(1)—O(3):2.557 (31) Å) contacts that might be regarded as secondary bonds (He & Zhu, 2003) complete a distorted octahedron. The Cu···Cui (i = 1 - x, -y, -z) distance bridged by the dpa ligands is 6.136 (16) Å. Extensive C—H···O hydrogen bonds link molecules into a three-dimensional network.(Table 2, Fig.2).

Related literature top

For related literature, see: Bu et al. (2004); He et al. (2007); Huang et al. (2004); Long et al. (2001); Ma et al. (2003); Rao et al. (2004); Yaghi et al. (2003); Yang et al. (2002); Zhang et al. (2004); Zhu et al. (2001); He & Zhu (2003).

Experimental top

A solution of Cu(NO3)2.6H2O(0.0705 g) in 5 ml of water was added dropwise under continuous stirring to an aqueous solution (5 ml) of diphenyl-2,2'-dicarboxylic acid (0.0734 g) and 2,2'-bipyridine (0.0312 g). The resulting mixture was then transferred into a 25 ml Teflon-lined stainless steel vessel, which was sealed and heated to 423 K for 72 h, then cooled to room temperature. The block blue single crystals were obtained.

Refinement top

The phenyl H atoms were positioned geometrically and allowed to ride during subsequent refinement, with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: SMART (Siemens, 1994); cell refinement: SAINT (Siemens, 1994); data reduction: SAINT (Siemens, 1994); 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
[Figure 1] Fig. 1. View of the structure of compound (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 35% probability level; H-atoms are shown as small spheres of arbitrary radius.
[Figure 2] Fig. 2. View of the 3D hydrogen-bonded network in the packing of the title compound.The packing is viewed along the b axis; C—H···O interactions are shown as dashed lines.
Bis(µ-biphenyl-2,2'-dicarboxylato)bis[(2,2'-bipyridine)copper(II)] top
Crystal data top
[Cu2(C14H8O4)2(C10H8N2)2]F000 = 940
Mr = 1839.75Dx = 1.561 Mg m3
Monoclinic, P21/cMo Kα radiation
λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 19150 reflections
a = 11.234 (2) Åθ = 3.1–27.4º
b = 13.336 (3) ŵ = 1.15 mm1
c = 15.431 (6) ÅT = 293 (2) K
β = 122.16 (2)ºBlock, blue
V = 1957.1 (9) Å30.40 × 0.26 × 0.23 mm
Z = 2
Data collection top
Siemens SMART CCD area-detector
diffractometer
4472 independent reflections
Radiation source: fine-focus sealed tube3708 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.046
T = 293(2) Kθmax = 27.4º
ω scansθmin = 3.1º
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 14→14
Tmin = 0.708, Tmax = 0.771k = 17→17
18687 measured reflectionsl = 18→19
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.118  w = 1/[σ2(Fo2) + (0.08P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
4472 reflectionsΔρmax = 0.29 e Å3
280 parametersΔρmin = 0.60 e Å3
Primary atom site location: structure-invariant direct methodsExtinction correction: none
Crystal data top
[Cu2(C14H8O4)2(C10H8N2)2]V = 1957.1 (9) Å3
Mr = 1839.75Z = 2
Monoclinic, P21/cMo Kα
a = 11.234 (2) ŵ = 1.15 mm1
b = 13.336 (3) ÅT = 293 (2) K
c = 15.431 (6) Å0.40 × 0.26 × 0.23 mm
β = 122.16 (2)º
Data collection top
Siemens SMART CCD area-detector
diffractometer
4472 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
3708 reflections with I > 2σ(I)
Tmin = 0.708, Tmax = 0.771Rint = 0.046
18687 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.036280 parameters
wR(F2) = 0.118H-atom parameters constrained
S = 1.04Δρmax = 0.29 e Å3
4472 reflectionsΔρmin = 0.60 e Å3
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
xyzUiso*/Ueq
Cu10.63909 (3)0.160660 (19)0.059678 (18)0.02914 (12)
O10.70349 (16)0.04363 (11)0.03157 (11)0.0354 (4)
O20.8638 (2)0.16096 (12)0.10287 (15)0.0530 (5)
O30.62962 (19)0.15631 (14)0.16045 (14)0.0480 (5)
O40.47467 (16)0.21452 (12)0.00754 (11)0.0374 (4)
N10.68794 (18)0.10223 (14)0.15551 (13)0.0320 (4)
N20.63566 (18)0.28542 (14)0.13069 (14)0.0331 (4)
C10.7186 (2)0.00573 (19)0.15928 (18)0.0406 (5)
H1A0.72270.03900.11150.049*
C20.7441 (3)0.0289 (2)0.2320 (2)0.0504 (7)
H2A0.76640.09590.23270.060*
C30.7361 (3)0.0368 (2)0.3032 (2)0.0531 (7)
H3A0.75140.01450.35360.064*
C40.7051 (3)0.1367 (2)0.29961 (19)0.0462 (6)
H4A0.70020.18230.34700.055*
C50.6486 (3)0.3529 (2)0.2682 (2)0.0487 (7)
H5A0.65660.34290.32460.058*
C60.6319 (3)0.4472 (2)0.2420 (3)0.0585 (8)
H6A0.62960.50220.28000.070*
C70.6184 (3)0.4608 (2)0.1591 (2)0.0540 (7)
H7A0.60970.52480.13920.065*
C80.6181 (3)0.37789 (19)0.1068 (2)0.0444 (6)
H8A0.60530.38650.05250.053*
C90.6815 (2)0.16746 (17)0.22479 (17)0.0332 (5)
C100.6534 (2)0.27237 (17)0.20994 (17)0.0337 (5)
C110.8922 (2)0.08967 (16)0.20040 (15)0.0278 (4)
C120.8946 (2)0.01519 (16)0.20175 (15)0.0281 (4)
C130.9639 (2)0.06631 (17)0.29523 (16)0.0346 (5)
H13A0.96810.13600.29590.042*
C141.0260 (2)0.0142 (2)0.38647 (16)0.0405 (5)
H14A1.07030.04860.44840.049*
C151.0221 (2)0.0895 (2)0.38529 (17)0.0419 (6)
H15A1.06360.12490.44660.050*
C160.9568 (2)0.14064 (17)0.29350 (18)0.0365 (5)
H16A0.95590.21040.29370.044*
C170.8383 (2)0.14901 (14)0.10351 (17)0.0282 (4)
C180.7102 (2)0.19898 (15)0.04996 (16)0.0292 (4)
C190.6773 (2)0.25507 (18)0.03716 (18)0.0369 (5)
H19A0.59200.28900.07270.044*
C200.7682 (3)0.26123 (18)0.07140 (19)0.0412 (5)
H20A0.74460.29910.12900.049*
C210.8951 (2)0.21017 (18)0.01881 (19)0.0400 (5)
H21A0.95730.21310.04120.048*
C220.9287 (3)0.15476 (17)0.06719 (19)0.0366 (5)
H22A1.01370.12040.10180.044*
C230.8187 (2)0.07766 (15)0.10614 (16)0.0300 (4)
C240.5999 (2)0.18908 (16)0.07706 (17)0.0309 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.03431 (18)0.02951 (18)0.02666 (17)0.00125 (10)0.01828 (13)0.00287 (9)
O10.0386 (8)0.0330 (8)0.0287 (8)0.0015 (7)0.0138 (7)0.0053 (6)
O20.0586 (12)0.0359 (10)0.0433 (10)0.0155 (8)0.0128 (9)0.0077 (7)
O30.0446 (10)0.0630 (12)0.0467 (11)0.0160 (8)0.0313 (9)0.0260 (8)
O40.0328 (8)0.0494 (10)0.0328 (8)0.0021 (7)0.0193 (7)0.0047 (7)
N10.0321 (9)0.0371 (10)0.0286 (9)0.0026 (8)0.0174 (8)0.0026 (8)
N20.0323 (9)0.0339 (10)0.0325 (9)0.0008 (8)0.0168 (8)0.0031 (8)
C10.0441 (13)0.0396 (13)0.0410 (13)0.0049 (11)0.0247 (11)0.0004 (10)
C20.0523 (15)0.0506 (16)0.0521 (16)0.0115 (13)0.0304 (13)0.0044 (12)
C30.0485 (15)0.075 (2)0.0423 (14)0.0104 (14)0.0288 (12)0.0046 (13)
C40.0412 (13)0.0684 (17)0.0339 (12)0.0086 (12)0.0233 (11)0.0095 (12)
C50.0477 (15)0.0549 (17)0.0515 (16)0.0021 (12)0.0317 (13)0.0170 (12)
C60.0578 (17)0.0476 (16)0.074 (2)0.0064 (13)0.0380 (16)0.0293 (15)
C70.0522 (16)0.0322 (13)0.076 (2)0.0053 (12)0.0327 (15)0.0113 (12)
C80.0475 (14)0.0354 (13)0.0500 (15)0.0028 (11)0.0259 (12)0.0028 (11)
C90.0253 (10)0.0467 (13)0.0273 (11)0.0003 (9)0.0138 (9)0.0040 (9)
C100.0268 (10)0.0414 (13)0.0313 (11)0.0001 (9)0.0144 (9)0.0076 (9)
C110.0261 (9)0.0282 (10)0.0298 (10)0.0002 (8)0.0154 (8)0.0003 (8)
C120.0282 (10)0.0304 (11)0.0269 (10)0.0008 (8)0.0154 (8)0.0001 (8)
C130.0383 (12)0.0330 (11)0.0337 (11)0.0039 (9)0.0199 (10)0.0056 (9)
C140.0416 (13)0.0515 (14)0.0261 (11)0.0053 (11)0.0166 (10)0.0062 (10)
C150.0418 (12)0.0521 (15)0.0258 (11)0.0020 (11)0.0139 (10)0.0096 (10)
C160.0386 (12)0.0322 (11)0.0365 (12)0.0003 (9)0.0184 (10)0.0055 (9)
C170.0328 (11)0.0243 (10)0.0302 (11)0.0037 (8)0.0186 (9)0.0015 (8)
C180.0345 (11)0.0242 (10)0.0320 (11)0.0024 (9)0.0198 (9)0.0004 (8)
C190.0403 (12)0.0332 (12)0.0382 (12)0.0040 (10)0.0215 (10)0.0099 (10)
C200.0530 (14)0.0362 (12)0.0422 (13)0.0049 (11)0.0305 (11)0.0083 (10)
C210.0462 (13)0.0398 (13)0.0487 (14)0.0066 (11)0.0352 (12)0.0014 (11)
C220.0339 (12)0.0389 (13)0.0394 (13)0.0010 (9)0.0211 (10)0.0007 (9)
C230.0357 (11)0.0280 (11)0.0294 (10)0.0010 (9)0.0194 (9)0.0010 (8)
C240.0346 (11)0.0257 (10)0.0360 (11)0.0013 (9)0.0211 (9)0.0030 (9)
Geometric parameters (Å, °) top
Cu1—O11.9640 (15)C6—H6A0.9300
Cu1—O4i1.9725 (16)C7—C81.370 (4)
Cu1—N21.9814 (19)C7—H7A0.9300
Cu1—N11.9897 (19)C8—H8A0.9300
Cu1—O22.434 (2)C9—C101.479 (3)
Cu1—C232.519 (2)C11—C161.394 (3)
Cu1—O3i2.557 (2)C11—C121.399 (3)
Cu1—C24i2.580 (2)C11—C171.505 (3)
O1—C231.273 (2)C12—C131.399 (3)
O2—C231.233 (3)C12—C231.503 (3)
O3—C241.225 (3)C13—C141.381 (3)
O3—Cu1i2.5567 (19)C13—H13A0.9300
O4—C241.280 (3)C14—C151.383 (4)
O4—Cu1i1.9725 (16)C14—H14A0.9300
N1—C11.342 (3)C15—C161.380 (3)
N1—C91.350 (3)C15—H15A0.9300
N2—C81.331 (3)C16—H16A0.9300
N2—C101.351 (3)C17—C181.390 (3)
C1—C21.377 (3)C17—C221.399 (3)
C1—H1A0.9300C18—C191.405 (3)
C2—C31.372 (4)C18—C241.509 (3)
C2—H2A0.9300C19—C201.379 (3)
C3—C41.385 (4)C19—H19A0.9300
C3—H3A0.9300C20—C211.387 (3)
C4—C91.377 (3)C20—H20A0.9300
C4—H4A0.9300C21—C221.384 (3)
C5—C61.365 (4)C21—H21A0.9300
C5—C101.383 (3)C22—H22A0.9300
C5—H5A0.9300C24—Cu1i2.580 (2)
C6—C71.378 (5)
O1—Cu1—O4i93.92 (7)C6—C7—H7A120.8
O1—Cu1—N2162.77 (7)N2—C8—C7122.5 (3)
O4i—Cu1—N295.38 (8)N2—C8—H8A118.8
O1—Cu1—N194.56 (7)C7—C8—H8A118.8
O4i—Cu1—N1160.15 (7)N1—C9—C4121.3 (2)
N2—Cu1—N181.35 (8)N1—C9—C10114.4 (2)
O1—Cu1—O258.55 (6)C4—C9—C10124.3 (2)
O4i—Cu1—O296.94 (8)N2—C10—C5121.0 (2)
N2—Cu1—O2105.83 (7)N2—C10—C9114.12 (19)
N1—Cu1—O2102.80 (8)C5—C10—C9124.9 (2)
O1—Cu1—C2329.83 (6)C16—C11—C12118.49 (19)
O4i—Cu1—C2395.07 (7)C16—C11—C17118.75 (19)
N2—Cu1—C23134.42 (7)C12—C11—C17122.34 (18)
N1—Cu1—C23101.19 (7)C11—C12—C13119.90 (19)
O2—Cu1—C2328.76 (6)C11—C12—C23122.91 (18)
O1—Cu1—O3i106.45 (7)C13—C12—C23117.11 (19)
O4i—Cu1—O3i56.28 (6)C14—C13—C12120.5 (2)
N2—Cu1—O3i90.78 (7)C14—C13—H13A119.7
N1—Cu1—O3i104.04 (7)C12—C13—H13A119.7
O2—Cu1—O3i150.22 (7)C13—C14—C15119.7 (2)
C23—Cu1—O3i130.98 (7)C13—C14—H14A120.2
O1—Cu1—C24i99.04 (7)C15—C14—H14A120.2
O4i—Cu1—C24i28.92 (6)C16—C15—C14120.2 (2)
N2—Cu1—C24i96.11 (7)C16—C15—H15A119.9
N1—Cu1—C24i131.58 (7)C14—C15—H15A119.9
O2—Cu1—C24i123.91 (8)C15—C16—C11121.2 (2)
C23—Cu1—C24i113.37 (7)C15—C16—H16A119.4
O3i—Cu1—C24i27.59 (6)C11—C16—H16A119.4
C23—O1—Cu1100.02 (13)C18—C17—C22118.57 (19)
C23—O2—Cu179.48 (13)C18—C17—C11125.76 (19)
C24—O3—Cu1i77.28 (13)C22—C17—C11115.66 (19)
C24—O4—Cu1i102.92 (13)C17—C18—C19119.05 (19)
C1—N1—C9119.4 (2)C17—C18—C24122.42 (19)
C1—N1—Cu1125.93 (16)C19—C18—C24118.37 (19)
C9—N1—Cu1114.61 (15)C20—C19—C18121.8 (2)
C8—N2—C10119.0 (2)C20—C19—H19A119.1
C8—N2—Cu1125.93 (17)C18—C19—H19A119.1
C10—N2—Cu1115.06 (15)C19—C20—C21119.1 (2)
N1—C1—C2121.8 (2)C19—C20—H20A120.4
N1—C1—H1A119.1C21—C20—H20A120.4
C2—C1—H1A119.1C22—C21—C20119.6 (2)
C3—C2—C1119.0 (3)C22—C21—H21A120.2
C3—C2—H2A120.5C20—C21—H21A120.2
C1—C2—H2A120.5C21—C22—C17121.9 (2)
C2—C3—C4119.5 (2)C21—C22—H22A119.1
C2—C3—H3A120.2C17—C22—H22A119.1
C4—C3—H3A120.2O2—C23—O1121.8 (2)
C9—C4—C3119.0 (2)O2—C23—C12120.6 (2)
C9—C4—H4A120.5O1—C23—C12117.53 (18)
C3—C4—H4A120.5O2—C23—Cu171.76 (13)
C6—C5—C10119.1 (3)O1—C23—Cu150.14 (10)
C6—C5—H5A120.4C12—C23—Cu1165.85 (15)
C10—C5—H5A120.4O3—C24—O4122.5 (2)
C5—C6—C7119.8 (2)O3—C24—C18121.2 (2)
C5—C6—H6A120.1O4—C24—C18116.28 (18)
C7—C6—H6A120.1O3—C24—Cu1i75.13 (13)
C8—C7—C6118.5 (3)O4—C24—Cu1i48.16 (10)
C8—C7—H7A120.8C18—C24—Cu1i161.10 (15)
Symmetry codes: (i) −x+1, −y, −z.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O10.932.583.081 (3)114
C4—H4A···O4ii0.932.593.378 (3)143
C5—H5A···O4ii0.932.513.304 (4)144
C6—H6A···O3iii0.932.253.162 (3)166
C16—H16A···O2iv0.932.483.192 (3)133
C19—H19A···O40.932.452.761 (3)100
Symmetry codes: (ii) −x+1, y−1/2, −z−1/2; (iii) x, −y−1/2, z−1/2; (iv) −x+2, y+1/2, −z+1/2.
Table 1
Selected geometric parameters (Å, °)
top
Cu1—O11.9640 (15)Cu1—O22.434 (2)
Cu1—O4i1.9725 (16)Cu1—C232.519 (2)
Cu1—N21.9814 (19)Cu1—O3i2.557 (2)
Cu1—N11.9897 (19)
O1—Cu1—O4i93.92 (7)O1—Cu1—N194.56 (7)
O1—Cu1—N2162.77 (7)O4i—Cu1—N1160.15 (7)
O4i—Cu1—N295.38 (8)N2—Cu1—N181.35 (8)
Symmetry codes: (i) −x+1, −y, −z.
Table 2
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O10.932.583.081 (3)114
C4—H4A···O4ii0.932.593.378 (3)143
C5—H5A···O4ii0.932.513.304 (4)144
C6—H6A···O3iii0.932.253.162 (3)166
C16—H16A···O2iv0.932.483.192 (3)133
C19—H19A···O40.932.452.761 (3)100
Symmetry codes: (ii) −x+1, y−1/2, −z−1/2; (iii) x, −y−1/2, z−1/2; (iv) −x+2, y+1/2, −z+1/2.
Acknowledgements top

This work was supported by a Project of Fujian Science and Technology Committee (grant No. 2006F5067), the Natural Science Foundation of Fujian Province (grant Nos. 2008J0172 and 2008J0237) and a Student Innovation Project of Zhangzhou Normal University (grant No. 08xscxxsyxm25).

references
References top

Bu, X. H., Tong, M. L., Chang, H. C., Kitagawa, S. & Batten, S. R. (2004). Angew. Chem. Int. Ed. 43, 192–195.

He, H.-Y., Zhou, Y.-L. & Gao, J. (2007). Acta Cryst. E63, m2007.

He, H.-Y. & Zhu, L.-G. (2003). Acta Cryst. E59, o174–o176.

Huang, X. C., Zhang, J. P., Lin, Y. Y., Yu, X. L. & Chen, X. M. (2004). Chem. Commun. pp. 1100–1101.

Long, L. S., Chen, X. M., Tong, M. L., Sun, Z. G., Ren, Y. P., Huang, R. B. & Zheng, L. S. (2001). J. Chem. Soc. Dalton Trans. pp. 2888–2890.

Ma, B. Q., Sun, H. L. & Gao, S. (2003). Chem. Commun. pp. 2164–2165.

Rao, C. N. R., Natarajan, S. & Vaidhyanathan, R. (2004). Angew. Chem. Int. Ed. 43, 1466–1496.

Sheldrick, G. M. (1996). SADABS. University of Göttingen,Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Siemens (1994). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.

Yaghi, O. M., O'Keeffe, M., Ockwig, N. W., Chae, H. K., Eddaoudi, M. & Kim, J. (2003). Nature (London), 423, 705–714.

Yang, S. Y., Long, L. S., Jiang, Y. B., Huang, R. B. & Zheng, L. S. (2002). Chem. Mater. 14, 3229–3230.

Zhang, J. P., Zheng, S. L., Huang, X. C. & Chen, X. M. (2004). Angew. Chem. Int. Ed. 43, 206–209.

Zhu, H. L., Tong, Y. X. & Chen, X. M. (2001). Transition Met. Chem. 26, 528–531.