supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportsimilar papers Open access

su2263 scheme

Acta Cryst. (2011). E67, m499-m500    [ doi:10.1107/S1600536811009949 ]

catena-Poly[copper(II)-{[mu]3-4,4'-dibromo-2,2'-[butane-1,4-diylbis(nitrilomethanylylidene)]diphenolato-[kappa]4N,O:N',O':O'}]

H. Kargar and R. Kia

Abstract top

The asymmetric unit of the title coordination polymer, [Cu(C18H16Br2N2O2)]n, consists of a Schiff base complex in which a crystallographic twofold rotation axis bisects the central C-C bonds of the n-butyl spacers of the designated Schiff base ligands, making symmetry-related dimer units, which are twisted around CuII atoms in a bis-bidentate coordination mode. In the crystal, these dimeric units are connected through Cu-O bonds, forming one-dimensional coordination polymers, which propagate along [001]. The CuII atom adopts a square-based pyramidal coordination geometry, being coordinated by two N and two O atoms of symmetry-related ligands and by a third O atom of a neighboring complex. Furthermore, intermolecular [pi]-[pi] interactions [centroid-centroid distance = 3.786 (2) Å] and C-H...O interactions stabilize the crystal packing.

Comment top

The design and construction of metal-organic coordination polymers (MOCPs) have attracted considerable attention, not only for their novel topologies but also for their potential in the area of magnetic applications and functional materials (Kido & Okamoto, 2002; Li et al., 2006; Eddaoudi et al., 2001; Dietzel et al., 2005). One of the key strategies in the construction of metal-organic coordination polymers is to select suitable bi- or multi-dentate bridging ligands. Among these, bis-bidentate NN- or NO-donor Schiff base ligands with aliphatic and aromatic spacers (Hannon et al., 1999; Lavalette et al., 2003) have attracted much attention because of the flexibility in their coordination modes and the resulting intermolecular interactions. The long chain aliphatic spacers or rigid aromatic spacers with large bite angles in these ligands favour the bis-bidentate coordination mode and allow the ligands to accomodate metal centers in one unit of the ligand. On the other hand, Schiff bases are one of the most prevalent ligands in coordination chemistry and their complexes are some of the most important stereochemical models in transition metal-organic chemistry, with their ease of preparation and structural variations (Granovski et al., 1993; Elmali et al., 2000).

The crystal structure of the chloro derivative, Poly[N,N'-Bis(5-chlorosalicylidene)-1,4-butanediaminato copper(II)], has been descibed in the previous paper (Kargar & Kia, 2011).

The molecular structure of the title complex (Fig. 1) consists of symmetry-related dimers in which the Schiff base ligands are twisted around CuII centers in a bis-bidentate coordinnation mode, having a crystallographic twofold rotation axis which passes through the central C—C bonds of the n-butyl spacers [C9—C9Ai and C18—C18Ai; symmetry code: (i) -x + 1, y, -z + 1/2].

In the crystal the dimer units are connected through Cu—O bonds, forming one-diensional coordination polymer running along the c axis (Fig. 2), in which the CuII atom adopts a square-based pyramidal coordination geometry. The CuII atoms are supported by the two nitrogen and oxygen atoms of the symmetry-related ligands and a third oxygen atom of neighboring complexes. The lengths of the intermolecular Cu1—O1i bonds [2.394 (3) Å Å; symetry code (i) -x, -y + 1, -z] is significantly shorter than the sum of the van der Waals (vdW) radii of these atoms [Cu, 1.43Å and O, 1.52 Å; Bondi, 1964]. There are different non-bonded internuclear Cu···Cu distances. The longer one is separated by the butyl spacers [4.718 Å], and the shorter one is in the centrosymmetric Cu2O2 rectangular unit [3.314 Å]. Furthermore, intermolecular π-π interactions stabilize the crystal packings with centroid to centroid distances of 3.786 (2)Å [Cg1 and Cg2 are the centroids of the rings (C1–C6) and (C10–C15)]. There are also C—H···O interactions present (Table 1).

Related literature top

For van der Waals radii, see: Bondi (1964). For background to coordination polymers, see: Kido & Okamoto (2002); Li et al. (2006); Eddaoudi et al. (2001); Dietzel et al. (2005). For background to bis-bidentate Schiff base complexes, see: Hannon et al. (1999); Lavalette et al. (2003). For the synthesis and structural variations of Schiff base complexes see: Granovski et al. (1993); Elmali et al. (2000). For the crystal structure of the chloro derivative, see: Kargar & Kia (2011).

Experimental top

The title complex was synthesized by the template method of mixing an ethanolic solution (50 ml) of 5-bromosalicylaldeyde (4 mmol), 1,4-butanediamine (2 mmol), and CuCl2.4H2O (2.1 mmol). After stirring at reflux conditions for 2 h, the solution was filtered and the resulting green solid was crystallized from ethanol, giving single crystals suitable for X-ray diffraction.

Refinement top

All H-atoms were positioned geometrically and constrained to ride on the parent atoms using the riding-model approximation: C—H = 0.93 - 0.97 Å with Uiso(H) = 1.2Ueq(C). In case of the large maximum residual density, located < 1 Å from the Br atoms, it was not possible to find any sign of twinning or missed atoms.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title complex, showing 40% probability displacement ellipsoids and the atomic numbering [H-atoms have been omitted for clarity; symmetry code for A suffix: -x + 1, -y, -z + 1].
[Figure 2] Fig. 2. The crystal packing, viewed down the b-axis, of the title complex, showing the one-dimensional coordination chain propagating along [001] (H-atoms have been omitted for clarity).
catena-Poly[copper(II)-{µ3-4,4'-dibromo-2,2'-[butane-1,4- diylbis(nitrilomethanylylidene)]diphenolato- κ4N,O:N',O':O'}] top
Crystal data top
[Cu(C18H16Br2N2O2)]F(000) = 2024
Mr = 515.69Dx = 1.969 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 9961 reflections
a = 24.0964 (9) Åθ = 2.4–34.8°
b = 10.5885 (3) ŵ = 5.86 mm−1
c = 15.3528 (5) ÅT = 100 K
β = 117.354 (3)°Block, green
V = 3479.2 (2) Å30.41 × 0.32 × 0.17 mm
Z = 8
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		6017 independent reflections
Radiation source: fine-focus sealed tube4887 reflections with I > 2σ(I)
graphiteRint = 0.037
φ and ω scansθmax = 32.0°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)		h = −35→35
Tmin = 0.197, Tmax = 0.439k = −15→15
36229 measured reflectionsl = −22→22
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.139H-atom parameters constrained
S = 1.19 w = 1/[σ2(Fo2) + (0.0486P)2 + 32.1161P]
where P = (Fo2 + 2Fc2)/3
6017 reflections(Δ/σ)max = 0.001
226 parametersΔρmax = 2.19 e Å−3
0 restraintsΔρmin = −0.73 e Å−3
Crystal data top
[Cu(C18H16Br2N2O2)]V = 3479.2 (2) Å3
Mr = 515.69Z = 8
Monoclinic, C2/cMo Kα radiation
a = 24.0964 (9) ŵ = 5.86 mm−1
b = 10.5885 (3) ÅT = 100 K
c = 15.3528 (5) Å0.41 × 0.32 × 0.17 mm
β = 117.354 (3)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		6017 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)		4887 reflections with I > 2σ(I)
Tmin = 0.197, Tmax = 0.439Rint = 0.037
36229 measured reflectionsθmax = 32.0°
Refinement top
R[F2 > 2σ(F2)] = 0.049 w = 1/[σ2(Fo2) + (0.0486P)2 + 32.1161P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.139Δρmax = 2.19 e Å−3
S = 1.19Δρmin = −0.73 e Å−3
6017 reflectionsAbsolute structure: ?
226 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
H-atom parameters constrained
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
Cu10.47745 (2)−0.03938 (5)0.38413 (4)0.01976 (11)
Br10.819293 (19)0.00198 (4)0.58443 (3)0.02766 (11)
Br20.134787 (18)0.00911 (4)0.11824 (3)0.02394 (10)
O10.54761 (13)0.0506 (3)0.4822 (2)0.0236 (6)
O20.40617 (13)−0.1341 (3)0.2998 (2)0.0252 (6)
N10.53131 (15)−0.1956 (3)0.4080 (2)0.0198 (6)
N20.43372 (16)0.1252 (3)0.3280 (3)0.0217 (6)
C10.60593 (18)0.0376 (4)0.4980 (3)0.0218 (7)
C20.64637 (19)0.1423 (4)0.5324 (3)0.0249 (8)
H2A0.63100.21950.54050.030*
C30.70866 (19)0.1318 (4)0.5542 (3)0.0247 (8)
H3A0.73470.20210.57550.030*
C40.73222 (18)0.0156 (4)0.5442 (3)0.0213 (7)
C50.69348 (17)−0.0878 (4)0.5073 (3)0.0209 (7)
H5A0.7094−0.16400.49870.025*
C60.62944 (17)−0.0775 (4)0.4828 (3)0.0194 (7)
C70.59134 (18)−0.1902 (4)0.4466 (3)0.0209 (7)
H7A0.6123−0.26570.45170.025*
C80.50307 (18)−0.3230 (4)0.3790 (3)0.0214 (7)
H8A0.4702−0.33230.39840.026*
H8B0.5347−0.38630.41380.026*
C90.47575 (17)−0.3465 (4)0.2686 (3)0.0208 (7)
H9A0.4544−0.42730.25330.025*
H9B0.4449−0.28170.23410.025*
C100.34829 (17)−0.0968 (4)0.2555 (3)0.0204 (7)
C110.30077 (18)−0.1890 (4)0.2123 (3)0.0223 (7)
H11A0.3120−0.27280.21150.027*
C120.23841 (18)−0.1575 (4)0.1715 (3)0.0224 (7)
H12A0.2080−0.21990.14500.027*
C130.22092 (17)−0.0308 (4)0.1703 (3)0.0194 (7)
C140.26555 (18)0.0625 (4)0.2037 (3)0.0218 (7)
H14A0.25340.14670.19800.026*
C150.32968 (18)0.0317 (4)0.2466 (3)0.0209 (7)
C160.37388 (19)0.1347 (4)0.2777 (3)0.0225 (7)
H16A0.35760.21570.25970.027*
C170.47047 (19)0.2436 (4)0.3495 (3)0.0229 (7)
H17A0.49370.25430.42000.028*
H17B0.44210.31450.32330.028*
C180.51627 (19)0.2440 (4)0.3057 (3)0.0243 (8)
H18A0.54270.31810.32890.029*
H18B0.54290.17010.32890.029*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.01465 (19)0.0223 (2)0.0209 (2)0.00107 (16)0.00695 (16)−0.00268 (18)
Br10.01623 (17)0.0374 (2)0.0292 (2)−0.00192 (15)0.01023 (15)−0.00306 (17)
Br20.01591 (17)0.0263 (2)0.0279 (2)0.00093 (13)0.00856 (15)0.00019 (15)
O10.0168 (12)0.0281 (15)0.0256 (14)−0.0010 (11)0.0096 (11)−0.0052 (12)
O20.0177 (12)0.0233 (14)0.0292 (15)0.0028 (10)0.0062 (11)−0.0047 (12)
N10.0179 (14)0.0220 (15)0.0194 (14)0.0005 (11)0.0086 (12)0.0001 (12)
N20.0222 (15)0.0200 (15)0.0246 (16)−0.0012 (12)0.0123 (13)−0.0036 (13)
C10.0171 (15)0.0266 (19)0.0196 (16)−0.0004 (14)0.0066 (13)−0.0041 (15)
C20.0224 (17)0.0256 (19)0.0271 (19)−0.0002 (15)0.0117 (16)−0.0049 (16)
C30.0213 (17)0.0268 (19)0.0262 (19)−0.0051 (14)0.0111 (15)−0.0053 (16)
C40.0159 (15)0.031 (2)0.0174 (16)−0.0006 (14)0.0083 (13)−0.0012 (14)
C50.0178 (15)0.0236 (18)0.0198 (16)0.0000 (13)0.0075 (13)−0.0022 (14)
C60.0174 (15)0.0227 (17)0.0169 (15)0.0002 (13)0.0068 (13)−0.0002 (13)
C70.0199 (16)0.0220 (17)0.0196 (16)0.0022 (13)0.0080 (14)−0.0004 (14)
C80.0186 (16)0.0206 (17)0.0245 (18)−0.0019 (13)0.0095 (14)0.0003 (14)
C90.0165 (15)0.0222 (17)0.0234 (17)−0.0019 (13)0.0089 (14)−0.0014 (14)
C100.0187 (16)0.0234 (18)0.0183 (16)0.0015 (13)0.0078 (13)−0.0005 (14)
C110.0186 (16)0.0224 (18)0.0223 (18)0.0013 (13)0.0062 (14)−0.0005 (14)
C120.0184 (16)0.0235 (18)0.0222 (17)0.0007 (13)0.0067 (14)0.0004 (15)
C130.0141 (14)0.0234 (17)0.0177 (16)0.0025 (12)0.0047 (12)0.0018 (13)
C140.0179 (16)0.0194 (17)0.0268 (18)0.0008 (13)0.0091 (14)0.0011 (14)
C150.0196 (16)0.0221 (17)0.0188 (16)0.0018 (13)0.0070 (13)−0.0004 (14)
C160.0219 (17)0.0210 (17)0.0254 (18)0.0002 (14)0.0115 (15)−0.0023 (15)
C170.0221 (17)0.0208 (18)0.0286 (19)−0.0033 (14)0.0140 (15)−0.0034 (15)
C180.0213 (17)0.0277 (19)0.0270 (19)−0.0019 (14)0.0138 (15)−0.0010 (15)
Geometric parameters (Å, °) top
Cu1—O21.894 (3)C7—H7A0.9300
Cu1—O11.922 (3)C8—C91.530 (6)
Cu1—N22.014 (4)C8—H8A0.9700
Cu1—N12.029 (3)C8—H8B0.9700
Cu1—O1i2.393 (3)C9—C9ii1.519 (7)
Br1—C41.901 (4)C9—H9A0.9700
Br2—C131.898 (4)C9—H9B0.9700
O1—C11.319 (5)C10—C111.416 (5)
O1—Cu1i2.393 (3)C10—C151.420 (6)
O2—C101.301 (5)C11—C121.377 (5)
N1—C71.288 (5)C11—H11A0.9300
N1—C81.484 (5)C12—C131.404 (6)
N2—C161.289 (5)C12—H12A0.9300
N2—C171.481 (5)C13—C141.374 (5)
C1—C61.408 (6)C14—C151.412 (5)
C1—C21.409 (6)C14—H14A0.9300
C2—C31.384 (6)C15—C161.444 (6)
C2—H2A0.9300C16—H16A0.9300
C3—C41.393 (6)C17—C181.534 (5)
C3—H3A0.9300C17—H17A0.9700
C4—C51.380 (6)C17—H17B0.9700
C5—C61.414 (5)C18—C18ii1.519 (8)
C5—H5A0.9300C18—H18A0.9700
C6—C71.451 (6)C18—H18B0.9700
O2—Cu1—O1173.11 (14)C9—C8—H8A109.1
O2—Cu1—N291.94 (13)N1—C8—H8B109.1
O1—Cu1—N290.31 (14)C9—C8—H8B109.1
O2—Cu1—N189.76 (13)H8A—C8—H8B107.8
O1—Cu1—N190.18 (13)C9ii—C9—C8113.8 (4)
N2—Cu1—N1161.46 (14)C9ii—C9—H9A108.8
O2—Cu1—O1i93.04 (12)C8—C9—H9A108.8
O1—Cu1—O1i80.22 (12)C9ii—C9—H9B108.8
N2—Cu1—O1i96.98 (12)C8—C9—H9B108.8
N1—Cu1—O1i101.37 (12)H9A—C9—H9B107.7
C1—O1—Cu1124.9 (3)O2—C10—C11118.6 (4)
C1—O1—Cu1i120.3 (3)O2—C10—C15123.8 (4)
Cu1—O1—Cu1i99.78 (12)C11—C10—C15117.6 (3)
C10—O2—Cu1127.9 (3)C12—C11—C10121.7 (4)
C7—N1—C8116.2 (3)C12—C11—H11A119.2
C7—N1—Cu1122.4 (3)C10—C11—H11A119.2
C8—N1—Cu1121.3 (2)C11—C12—C13119.7 (4)
C16—N2—C17117.2 (4)C11—C12—H12A120.2
C16—N2—Cu1123.0 (3)C13—C12—H12A120.2
C17—N2—Cu1119.7 (3)C14—C13—C12120.2 (3)
O1—C1—C6122.4 (4)C14—C13—Br2120.9 (3)
O1—C1—C2118.8 (4)C12—C13—Br2118.8 (3)
C6—C1—C2118.8 (4)C13—C14—C15120.6 (4)
C3—C2—C1121.0 (4)C13—C14—H14A119.7
C3—C2—H2A119.5C15—C14—H14A119.7
C1—C2—H2A119.5C14—C15—C10119.7 (4)
C2—C3—C4119.7 (4)C14—C15—C16117.6 (4)
C2—C3—H3A120.2C10—C15—C16122.7 (3)
C4—C3—H3A120.2N2—C16—C15126.2 (4)
C5—C4—C3120.9 (4)N2—C16—H16A116.9
C5—C4—Br1120.7 (3)C15—C16—H16A116.9
C3—C4—Br1118.4 (3)N2—C17—C18112.4 (3)
C4—C5—C6119.9 (4)N2—C17—H17A109.1
C4—C5—H5A120.1C18—C17—H17A109.1
C6—C5—H5A120.1N2—C17—H17B109.1
C1—C6—C5119.7 (4)C18—C17—H17B109.1
C1—C6—C7122.9 (3)H17A—C17—H17B107.9
C5—C6—C7117.4 (4)C18ii—C18—C17113.0 (4)
N1—C7—C6126.3 (4)C18ii—C18—H18A109.0
N1—C7—H7A116.8C17—C18—H18A109.0
C6—C7—H7A116.8C18ii—C18—H18B109.0
N1—C8—C9112.6 (3)C17—C18—H18B109.0
N1—C8—H8A109.1H18A—C18—H18B107.8
N2—Cu1—O1—C1−124.9 (3)O1—C1—C6—C5−175.7 (4)
N1—Cu1—O1—C136.6 (3)C2—C1—C6—C53.5 (6)
O1i—Cu1—O1—C1138.1 (4)O1—C1—C6—C71.4 (6)
N2—Cu1—O1—Cu1i97.03 (13)C2—C1—C6—C7−179.3 (4)
N1—Cu1—O1—Cu1i−101.51 (13)C4—C5—C6—C1−1.3 (6)
O1i—Cu1—O1—Cu1i0.0C4—C5—C6—C7−178.6 (4)
N2—Cu1—O2—C10−21.9 (4)C8—N1—C7—C6−178.3 (4)
N1—Cu1—O2—C10176.6 (4)Cu1—N1—C7—C63.4 (6)
O1i—Cu1—O2—C1075.2 (4)C1—C6—C7—N113.1 (6)
O2—Cu1—N1—C7164.8 (3)C5—C6—C7—N1−169.7 (4)
O1—Cu1—N1—C7−22.1 (3)C7—N1—C8—C9−101.6 (4)
N2—Cu1—N1—C769.4 (6)Cu1—N1—C8—C976.7 (4)
O1i—Cu1—N1—C7−102.2 (3)N1—C8—C9—C9ii64.2 (3)
O2—Cu1—N1—C8−13.5 (3)Cu1—O2—C10—C11−167.0 (3)
O1—Cu1—N1—C8159.6 (3)Cu1—O2—C10—C1513.7 (6)
N2—Cu1—N1—C8−108.9 (5)O2—C10—C11—C12174.4 (4)
O1i—Cu1—N1—C879.6 (3)C15—C10—C11—C12−6.3 (6)
O2—Cu1—N2—C1617.4 (3)C10—C11—C12—C131.5 (6)
O1—Cu1—N2—C16−156.1 (3)C11—C12—C13—C144.2 (6)
N1—Cu1—N2—C16112.4 (5)C11—C12—C13—Br2−177.6 (3)
O1i—Cu1—N2—C16−75.9 (3)C12—C13—C14—C15−4.9 (6)
O2—Cu1—N2—C17−166.6 (3)Br2—C13—C14—C15177.0 (3)
O1—Cu1—N2—C1719.9 (3)C13—C14—C15—C10−0.1 (6)
N1—Cu1—N2—C17−71.6 (5)C13—C14—C15—C16178.4 (4)
O1i—Cu1—N2—C17100.1 (3)O2—C10—C15—C14−175.2 (4)
Cu1—O1—C1—C6−31.8 (6)C11—C10—C15—C145.6 (6)
Cu1i—O1—C1—C698.5 (4)O2—C10—C15—C166.4 (6)
Cu1—O1—C1—C2148.9 (3)C11—C10—C15—C16−172.8 (4)
Cu1i—O1—C1—C2−80.7 (4)C17—N2—C16—C15178.4 (4)
O1—C1—C2—C3177.1 (4)Cu1—N2—C16—C15−5.6 (6)
C6—C1—C2—C3−2.2 (6)C14—C15—C16—N2171.5 (4)
C1—C2—C3—C4−1.4 (7)C10—C15—C16—N2−10.1 (7)
C2—C3—C4—C53.8 (6)C16—N2—C17—C18−118.7 (4)
C2—C3—C4—Br1−175.2 (3)Cu1—N2—C17—C1865.1 (4)
C3—C4—C5—C6−2.5 (6)N2—C17—C18—C18ii65.9 (3)
Br1—C4—C5—C6176.6 (3)
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+1, y, −z+1/2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C9—H9B···O20.972.282.973 (5)128
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C9—H9B···O20.972.282.973 (5)128
Acknowledgements top

HK thans PNU for support of this work. RK thanks the Science and Research Branch, Islamic Azad University.

references
References top

Bondi, A. (1964). J. Phys. Chem. 68, 441–451.

Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Dietzel, P. D. C., Morita, Y., Blom, R. & Fjellvag, H. (2005). Angew. Chem. Int. Ed. 44, 1483–1492.

Eddaoudi, M., Moler, D., Li, H., Reineke, T. M., O'Keeffe, M. & Yaghi, O. M. (2001). Acc. Chem. Res. 34, 319–330.

Elmali, A., Zeyrek, C. T., Elerman, Y. & Svoboda, I. (2000). Acta Cryst. C56, 1302–1304.

Granovski, A. D., Nivorozhkin, A. L. & Minkin, V. I. (1993). Coord. Chem. Rev. 126, 1–69.

Hannon, M. J., Painting, L. C. & Alcock, N. W. (1999). Chem. Commun. pp. 2023–2024.

Kargar, H. & Kia, R. (2011). Acta Cryst. E67, [SU2262]

Kido, J. & Okamoto, Y. (2002). Chem. Rev. 102, 2357–2368.

Lavalette, A., Tuna, F., Clarkson, G., Alcock, N. W. & Hannon, M. J. (2003). Chem. Commun. pp. 2666–2667.

Li, Y., Zheng, F.-K., Liu, X., Zou, W.-Q., Guo, G.-C., Lu, C.-Z. & Huang, J.-S. (2006). Inorg. Chem. 45, 6308–6316.

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

Spek, A. L. (2009). Acta Cryst. D65, 148–155.