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In the title compound, [Nd2(C4H4O4)2(C2O4)(H2O)2]n, the flexible succinate anion assumes the gauche conformation and bridges the nine-coordinate Nd atoms to generate two-dimensional layers parallel to (010). The coordination polymer layers are linked into a three-dimensional framework by the rigid oxalate ligands. The oxalate ions are located on a center of inversion.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107045143/sk3164sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107045143/sk3164Isup2.hkl
Contains datablock I

CCDC reference: 669147

Comment top

A great effort has been devoted to the design and synthesis of functional materials, an area of intense activity and tremendous potential significance (Bradshaw et al., 2005; Kitagawa et al., 2004; Rao et al., 2004). Weak intermolecular forces, such as hydrogen bonding, ππ stacking, dipole–dipole attractions and van der Waals interactions, have been studied in depth and can be used in the design of molecular solids with specific supramolecular structures and functions (Fujita et al., 2005; Noveron et al., 2002; Bourne et al., 2001). The self-assemblies of supramolecular complexes can be achieved by controlling the noncovalent interactions among the ligands, which are, in most cases, organic groups (Hunks et al., 2002; Braga et al., 2000).

Utilization of rigid aromatic dicarboxylate ligands has become an interesting strategy to construct neutral nanoporous coordination polymers (Serre et al., 2002; Li et al., 1999; Chui et al., 1999). Unlike the rigid dicarboxylate spacer ligands, saturated aliphatic dicarboxylate ligands exhibit conformational and coordination versatility due to their single-bonded carbon chains, which are viewed as important flexible spacer ligands. Under mild ambient and hydrothermal conditions, self-assembly of metal cations with α,ω-dicarboxylate anions such as succinate afforded a variety of supramolecular motifs, where the discrete metal–oxygen polyhedra could be interconnected by organic linkers into polymeric layers and three-dimensional frameworks. Unfortunately, such three-dimensional frameworks exhibit normally little porosity (Zhang et al., 2006; Guillou et al., 2003; Forster & Cheetham, 2002). To overcome this problem, our recent research has been intensively focused on simultaneous utilization of rigid dicarboxylate and flexible α,ω-dicarboxylate ligands to construct coordination polymers. We report here a novel lanthanide coordination polymer, [Nd2(C4H4O4)2(C2O4)(H2O)2], (I), containing oxalate ligands, one of the simplest rigid dicarboxylate ligands, and flexible succinate ligands.

In (I), the Nd atoms are bridged by flexible succinate ligands to generate two-dimensional layers, which are pillared by rigid oxalate ligands into higher-dimensional frameworks. As shown in Fig. 1, the asymmetric unit consists of one Nd3+ cation, one succinate anion, one-half of an oxalate anion and one aqua ligand. The Nd atoms are each coordinated by nine O atoms of five succinate anions, one oxalate anion and one aqua ligand to complete a distorted tricapped trigonal–prismatic geometry. The succinate anions assume a gauche conformation, in which both carboxylate groups function similarly; each carboxylate group chelates one Nd atom, with one O atom (O1 and O4) additionally bonded to another Nd atom. The Nd1iii—O4 bond distance is 2.925 (5) Å (symmetry code as in Table 1); however, the others Nd1—O bond distances range from 2.372 (5) to 2.580 (5) Å, which means that only very weak coordination interactions exist between atoms O4 and Nd1iii. Through the terminal carboxylate bridging interactions, the polyhedra are edged-shared to generate metal–oxygen chains extending infinitely along the [001] direction, in which the adjacent Nd···Nd distances are 4.447 (2) and 4.190 (1) Å. Along the [100] direction, the chains are linked by the gauche succinate anions into layers parallel to (010) (Fig. 2). Both lengths and angles within the succinate anions exhibit normal values (Seguatni et al., 2004). The oxalate ions are located on a center of inversion and act as double bidentate (tetradentate) ligands in a linear chain that connects two Nd atoms in two different layers to form a three-dimensional framework (Fig. 3). The aqua ligands donate H atoms to carboxylate atoms O2 and O5 to form hydrogen bonds (Table 2), which make a significant contribution to the stabilization of the crystal structure.

Related literature top

For related literature, see: Bourne et al. (2001); Bradshaw et al. (2005); Braga et al. (2000); Chui et al. (1999); Forster & Cheetham (2002); Fujita et al. (2005); Guillou et al. (2003); Hunks et al. (2002); Kitagawa et al. (2004); Li et al. (1999); Noveron et al. (2002); Rao et al. (2004); Seguatni et al. (2004); Serre et al. (2002); Zhang et al. (2006).

Experimental top

A mixture of NdCl3·6H2O (1.00 mmol, 0.36 g), oxalic acid (0.50 mmol, 0.05 g), succinic acid (0.50 mmol, 0.06 g), NaOH (2.00 mmol, 0.08 g) and water (10.0 ml) was heated in a 23 ml stainless steel reactor with a Teflon liner at 443 K for 48 h. The orange plate-like crystals were filtered off, and washed with water and acetone (yield 46% based on Nd).

Refinement top

H atoms attached to C atoms were included at calculated positions and treated as riding atoms [C—H = 0.97 Å and Uiso(H) = 1.2Ueq(C)]. The water H atoms were found in a diffrence map, relocated in idealized positions (O—H = 0.85 Å) and refined as riding atoms [Uiso(H) = 1.2Ueq(O)].

Computing details top

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2004); software used to prepare material for publication: SHELXTL (Bruker, 2004).

Figures top
[Figure 1] Fig. 1. The structure of the title compound, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. [Symmetry codes: (i) x + 1, y, z + 1; (ii) −x + 1, −y, −z; (iii) −x + 2, −y, −z; (iv) −x + 2, −y + 1, −z + 1; (v) x − 1, y, z − 1.]
[Figure 2] Fig. 2. The two-dimensional layer structure formed by the connectivity between the Nd atoms and the succinate ligands present in the title compound. H atoms attached to C atoms have been omitted for clarity.
[Figure 3] Fig. 3. The three-dimensional framework of the title compound.
Poly[bis[aquaneodymium(III)]-µ2-oxalato-di-µ4-succinato] top
Crystal data top
[Nd2(C4H4O4)2(C2O4)(H2O)2]Z = 2
Mr = 322.34F(000) = 304
Triclinic, P1Dx = 2.779 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.8792 (4) ÅCell parameters from 255 reflections
b = 7.6203 (5) Åθ = 1.9–27.1°
c = 8.0401 (5) ŵ = 6.74 mm1
α = 102.281 (2)°T = 291 K
β = 104.125 (1)°Plate, orange
γ = 101.422 (1)°0.23 × 0.17 × 0.06 mm
V = 385.23 (4) Å3
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
1572 independent reflections
Radiation source: fine-focus sealed tube1487 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.027
ϕ and ω scansθmax = 27.8°, θmin = 2.7°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
h = 88
Tmin = 0.259, Tmax = 0.662k = 79
2232 measured reflectionsl = 109
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)] = 0.045H-atom parameters constrained
wR(F2) = 0.113 w = 1/[σ2(Fo2) + (0.0895P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.10(Δ/σ)max = 0.001
1572 reflectionsΔρmax = 0.40 e Å3
119 parametersΔρmin = 0.85 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.124 (8)
Crystal data top
[Nd2(C4H4O4)2(C2O4)(H2O)2]γ = 101.422 (1)°
Mr = 322.34V = 385.23 (4) Å3
Triclinic, P1Z = 2
a = 6.8792 (4) ÅMo Kα radiation
b = 7.6203 (5) ŵ = 6.74 mm1
c = 8.0401 (5) ÅT = 291 K
α = 102.281 (2)°0.23 × 0.17 × 0.06 mm
β = 104.125 (1)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
1572 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
1487 reflections with I > 2σ(I)
Tmin = 0.259, Tmax = 0.662Rint = 0.027
2232 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.113H-atom parameters constrained
S = 1.10Δρmax = 0.40 e Å3
1572 reflectionsΔρmin = 0.85 e Å3
119 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
xyzUiso*/Ueq
Nd11.03773 (3)0.10965 (3)0.28857 (3)0.0157 (3)
O10.2017 (7)0.1049 (7)0.4071 (6)0.0230 (11)
O20.3237 (7)0.1005 (7)0.1324 (6)0.0258 (11)
O30.8557 (10)0.1832 (9)0.2685 (7)0.0421 (15)
O40.9428 (7)0.1762 (8)0.0093 (7)0.0325 (13)
O50.8025 (6)0.2993 (6)0.3751 (6)0.0220 (11)
O60.7872 (7)0.5637 (7)0.5514 (7)0.0237 (11)
O71.3735 (6)0.1833 (7)0.2274 (6)0.0315 (12)
H7B1.49160.22990.30590.038*
H7A1.35460.15390.11550.038*
C10.3427 (8)0.1700 (8)0.2575 (8)0.0166 (13)
C20.5217 (9)0.3333 (9)0.2330 (9)0.0272 (15)
H2A0.47350.44530.21800.033*
H2B0.56290.31640.34120.033*
C30.7104 (10)0.3626 (10)0.0777 (9)0.0233 (16)
H3A0.79370.49010.04640.028*
H3B0.66570.34450.02440.028*
C40.8424 (10)0.2328 (10)0.1164 (9)0.0211 (15)
C50.8817 (10)0.4613 (10)0.4791 (9)0.0202 (15)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Nd10.0126 (3)0.0161 (3)0.0179 (3)0.00272 (17)0.00379 (16)0.00555 (17)
O10.016 (2)0.028 (3)0.019 (2)0.0007 (18)0.0006 (15)0.0066 (18)
O20.024 (2)0.024 (3)0.025 (2)0.0038 (18)0.0044 (17)0.0097 (19)
O30.063 (4)0.040 (3)0.039 (3)0.032 (3)0.025 (3)0.014 (2)
O40.024 (2)0.039 (3)0.038 (3)0.009 (2)0.003 (2)0.025 (2)
O50.0148 (18)0.017 (2)0.027 (2)0.0000 (16)0.0007 (16)0.0015 (17)
O60.017 (2)0.015 (2)0.041 (3)0.0024 (17)0.0114 (18)0.0077 (19)
O70.0160 (19)0.048 (3)0.021 (2)0.002 (2)0.0056 (15)0.0023 (19)
C10.016 (2)0.014 (3)0.019 (3)0.005 (2)0.0030 (19)0.004 (2)
C20.019 (3)0.024 (3)0.040 (4)0.003 (2)0.006 (2)0.018 (3)
C30.018 (3)0.022 (3)0.024 (3)0.002 (2)0.005 (2)0.001 (2)
C40.017 (3)0.021 (3)0.022 (3)0.002 (2)0.003 (2)0.007 (2)
C50.022 (3)0.017 (3)0.023 (3)0.007 (3)0.005 (2)0.009 (2)
Geometric parameters (Å, º) top
Nd1—O1i2.443 (4)O5—C51.262 (8)
Nd1—O1ii2.580 (5)O6—C51.249 (8)
Nd1—O2ii2.523 (5)O7—H7B0.8512
Nd1—O3iii2.469 (5)O7—H7A0.8500
Nd1—O42.372 (5)C1—C21.508 (9)
Nd1—O4iii2.925 (5)C2—C31.507 (9)
Nd1—O52.498 (4)C2—H2A0.9700
Nd1—O6iv2.449 (5)C2—H2B0.9700
Nd1—O72.460 (5)C3—C41.504 (8)
O1—C11.273 (7)C3—H3A0.9700
O2—C11.254 (9)C3—H3B0.9700
O3—C41.233 (9)C5—C5iv1.542 (14)
O4—C41.283 (9)
O4—Nd1—O1i166.8 (2)O7—Nd1—C4iii66.4 (2)
O4—Nd1—O6iv92.94 (19)O3iii—Nd1—C4iii22.9 (2)
O1i—Nd1—O6iv75.38 (17)O5—Nd1—C4iii157.23 (16)
O4—Nd1—O777.84 (17)O2ii—Nd1—C4iii81.86 (16)
O1i—Nd1—O792.55 (16)O1ii—Nd1—C4iii87.78 (18)
O6iv—Nd1—O772.63 (16)O4iii—Nd1—C4iii24.72 (17)
O4—Nd1—O3iii112.95 (17)C1ii—Nd1—C4iii82.68 (17)
O1i—Nd1—O3iii72.80 (17)C1—O1—Nd1v152.4 (5)
O6iv—Nd1—O3iii133.94 (19)C1—O1—Nd1ii93.7 (4)
O7—Nd1—O3iii76.4 (2)Nd1v—O1—Nd1ii113.04 (16)
O4—Nd1—O585.96 (16)C1—O2—Nd1ii96.9 (3)
O1i—Nd1—O594.53 (15)C4—O3—Nd1iii105.9 (5)
O6iv—Nd1—O565.49 (14)C4—O4—Nd1158.9 (5)
O7—Nd1—O5134.01 (16)C4—O4—Nd1iii83.0 (4)
O3iii—Nd1—O5148.5 (2)Nd1—O4—Nd1iii113.80 (19)
O4—Nd1—O2ii75.66 (19)C5—O5—Nd1118.9 (4)
O1i—Nd1—O2ii117.27 (18)C5—O6—Nd1iv120.5 (5)
O6iv—Nd1—O2ii140.03 (14)Nd1—O7—H7B125.5
O7—Nd1—O2ii138.15 (15)Nd1—O7—H7A109.9
O3iii—Nd1—O2ii84.8 (2)H7B—O7—H7A124.6
O5—Nd1—O2ii75.45 (14)O2—C1—O1118.6 (6)
O4—Nd1—O1ii125.73 (14)O2—C1—C2122.0 (5)
O1i—Nd1—O1ii66.96 (16)O1—C1—C2119.4 (6)
O6iv—Nd1—O1ii123.04 (16)O2—C1—Nd1ii58.1 (3)
O7—Nd1—O1ii146.29 (15)O1—C1—Nd1ii60.8 (4)
O3iii—Nd1—O1ii72.1 (2)C2—C1—Nd1ii171.9 (4)
O5—Nd1—O1ii76.38 (15)C3—C2—C1115.3 (6)
O2ii—Nd1—O1ii50.39 (15)C3—C2—H2A108.5
O4—Nd1—O4iii66.20 (19)C1—C2—H2A108.5
O1i—Nd1—O4iii118.86 (16)C3—C2—H2B108.5
O6iv—Nd1—O4iii138.51 (17)C1—C2—H2B108.5
O7—Nd1—O4iii68.20 (14)H2A—C2—H2B107.5
O3iii—Nd1—O4iii46.79 (16)C4—C3—C2112.9 (5)
O5—Nd1—O4iii141.01 (12)C4—C3—H3A109.0
O2ii—Nd1—O4iii71.66 (14)C2—C3—H3A109.0
O1ii—Nd1—O4iii97.57 (16)C4—C3—H3B109.0
O4—Nd1—C1ii100.61 (18)C2—C3—H3B109.0
O1i—Nd1—C1ii92.30 (16)H3A—C3—H3B107.8
O6iv—Nd1—C1ii138.02 (15)O3—C4—O4120.3 (6)
O7—Nd1—C1ii149.00 (15)O3—C4—C3119.7 (6)
O3iii—Nd1—C1ii75.9 (2)O4—C4—C3120.0 (6)
O5—Nd1—C1ii75.98 (14)O3—C4—Nd1iii51.2 (4)
O2ii—Nd1—C1ii24.97 (17)O4—C4—Nd1iii72.3 (4)
O1ii—Nd1—C1ii25.51 (15)C3—C4—Nd1iii159.7 (4)
O4iii—Nd1—C1ii82.71 (15)O6—C5—O5126.3 (6)
O4—Nd1—C4iii90.32 (19)O6—C5—C5iv117.3 (7)
O1i—Nd1—C4iii94.15 (17)O5—C5—C5iv116.4 (7)
O6iv—Nd1—C4iii137.21 (17)
O1i—Nd1—O4—C4104.1 (14)Nd1v—O1—C1—O2172.6 (5)
O6iv—Nd1—O4—C476.7 (14)Nd1ii—O1—C1—O26.5 (5)
O7—Nd1—O4—C4148.2 (14)Nd1v—O1—C1—C24.6 (11)
O3iii—Nd1—O4—C4142.4 (14)Nd1ii—O1—C1—C2170.7 (4)
O5—Nd1—O4—C411.5 (14)Nd1v—O1—C1—Nd1ii166.1 (8)
O2ii—Nd1—O4—C464.5 (14)O2—C1—C2—C321.2 (8)
O1ii—Nd1—O4—C458.5 (14)O1—C1—C2—C3161.7 (5)
O4iii—Nd1—O4—C4140.5 (15)C1—C2—C3—C479.1 (9)
C1ii—Nd1—O4—C463.4 (14)Nd1iii—O3—C4—O423.0 (9)
C4iii—Nd1—O4—C4146.0 (13)Nd1iii—O3—C4—C3157.9 (6)
O4—Nd1—O5—C5104.9 (6)Nd1—O4—C4—O3162.7 (10)
O1i—Nd1—O5—C561.9 (5)Nd1iii—O4—C4—O318.6 (7)
O6iv—Nd1—O5—C59.8 (5)Nd1—O4—C4—C318.2 (18)
O7—Nd1—O5—C536.1 (6)Nd1iii—O4—C4—C3162.2 (7)
O3iii—Nd1—O5—C5125.9 (6)Nd1—O4—C4—Nd1iii144.1 (14)
O2ii—Nd1—O5—C5178.9 (6)C2—C3—C4—O333.3 (11)
O1ii—Nd1—O5—C5126.8 (6)C2—C3—C4—O4147.6 (7)
O4iii—Nd1—O5—C5148.0 (5)Nd1iv—O6—C5—O5170.5 (6)
C1ii—Nd1—O5—C5153.1 (6)Nd1iv—O6—C5—C5iv9.9 (11)
C4iii—Nd1—O5—C5173.9 (5)Nd1—O5—C5—O6170.6 (6)
Nd1ii—O2—C1—O16.7 (5)Nd1—O5—C5—C5iv9.0 (11)
Nd1ii—O2—C1—C2170.4 (4)
Symmetry codes: (i) x+1, y, z+1; (ii) x+1, y, z; (iii) x+2, y, z; (iv) x+2, y+1, z+1; (v) x1, y, z1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O7—H7A···O2vi0.851.902.745 (6)177
O7—H7B···O5vi0.852.002.777 (6)151
Symmetry code: (vi) x+1, y, z.

Experimental details

Crystal data
Chemical formula[Nd2(C4H4O4)2(C2O4)(H2O)2]
Mr322.34
Crystal system, space groupTriclinic, P1
Temperature (K)291
a, b, c (Å)6.8792 (4), 7.6203 (5), 8.0401 (5)
α, β, γ (°)102.281 (2), 104.125 (1), 101.422 (1)
V3)385.23 (4)
Z2
Radiation typeMo Kα
µ (mm1)6.74
Crystal size (mm)0.23 × 0.17 × 0.06
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.259, 0.662
No. of measured, independent and
observed [I > 2σ(I)] reflections
2232, 1572, 1487
Rint0.027
(sin θ/λ)max1)0.656
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.113, 1.10
No. of reflections1572
No. of parameters119
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.40, 0.85

Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2004).

Selected bond lengths (Å) top
Nd1—O1i2.443 (4)Nd1—O4iii2.925 (5)
Nd1—O1ii2.580 (5)Nd1—O52.498 (4)
Nd1—O2ii2.523 (5)Nd1—O6iv2.449 (5)
Nd1—O3iii2.469 (5)Nd1—O72.460 (5)
Nd1—O42.372 (5)
Symmetry codes: (i) x+1, y, z+1; (ii) x+1, y, z; (iii) x+2, y, z; (iv) x+2, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O7—H7A···O2v0.851.902.745 (6)177
O7—H7B···O5v0.852.002.777 (6)151
Symmetry code: (v) x+1, y, z.
 

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