Poly[[tetra­aquadi-μ₃-oxalato-μ₂-oxalato-diprasedymium(III)] dihydrate]

In the title compound, {[Pr₂(C₂O₄)₃(H₂O)₄]·2H₂O}_n, the three-dimensional network structure has the Pr^III ion coordinated by nine O atoms in a distorted tricapped trigonal-prismatic geometry. The coordinated and uncoordinated water mol­ecules inter­act with the carboxyl­ate O atoms to consolidate the network via O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.016
• wR factor = 0.035
• Data-to-parameter ratio = 10.7

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT417_ALERT_2_B Short Inter D-H..H-D       H7A    ..  H9A     ..       2.04 Ang.
PLAT417_ALERT_2_B Short Inter D-H..H-D       H8B    ..  H9A     ..       2.09 Ang.

Alert level C
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Pr1    --  O1      ..       5.14 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Pr1    --  O8      ..       5.11 su
PLAT041_ALERT_1_C Calc. and Reported SumFormula    Strings  Differ          ?
PLAT042_ALERT_1_C Calc. and Reported MoietyFormula Strings  Differ          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       2.00 Ratio
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.847(10) ......       3.00 su-Ra
              O7   -H7A     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.845(10) ......       3.00 su-Ra
              O7   -H7B     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.842(10) ......       3.00 su-Ra
              O8   -H8A     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(4), Rep   0.839(10) ......       4.00 su-Ra
              O9   -H9A     1.555   1.555
PLAT732_ALERT_1_C Angle   Calc      116(4), Rep   115.7(15) ......       2.67 su-Ra
              H8A  -O8   -H8B     1.555   1.555   1.555
PLAT732_ALERT_1_C Angle   Calc      117(4), Rep   117.4(16) ......       2.50 su-Ra
              H9B  -O9   -H9A     1.555   1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.847(10) ......       3.00 su-Ra
              O7   -H7A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.845(10) ......       3.00 su-Ra
              O7   -H7B     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.842(10) ......       3.00 su-Ra
              O8   -H8A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.842(10) ......       3.00 su-Ra
              O8   -H8A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(4), Rep   0.839(10) ......       4.00 su-Ra
              O9   -H9A     1.555   1.555
PLAT736_ALERT_1_C H...A   Calc     1.90(3), Rep   1.892(13) ......       2.31 su-Ra
              H7A  -O9      1.555   1.545
PLAT736_ALERT_1_C H...A   Calc     2.06(3), Rep   2.060(11) ......       2.73 su-Ra
              H8A  -O2      1.555   3.566
PLAT736_ALERT_1_C H...A   Calc     2.05(4), Rep   2.047(14) ......       2.86 su-Ra
              H9A  -O8      1.555   1.555

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          9
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       1.24 Ratio

   0 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
  20 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

  17 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Though complexes including oxalato and praseodymium(III) have been extensively investigated, the crystal structure of praseodymium oxalate with one-dimensional, two-dimensional and three-dimensional topologies and different solvent molecules have constantly being reported recently. In this paper, we would like to report the synthesis and crystal structure of a three-dimensional network complex including oxalato and praseodymium(III) with one lattice water molecule per unsymmetrical unit. The hydrothermal reaction of Pr₆O₁₁ and oxalic acid in H₂O afforded the Pr^III title polymeric complex, [(Pr(C₂O₄)_1.5(H₂O)₂).H₂O]_n. The Pr^III ion is coordinated by nine O atoms from two water molecules and four carboxylate groups of oxalate ligands in an irregular coordination geometry (Figure 1). Two oxalate groups of the oxalate anions bridge two symmetry-related Pr^III atoms, giving rise to a layer-like structure extending along [100] (Figure 2). These parallel layers are further connected via chelating coordination of oxalate anions into a three-dimensional network (Figure 3) along [010] plane. Moreover, the coordinated/non-coordinated water molecules interact with the carboxylate oxygen atoms from the layers via O—H···O hydrogen bonds (Table 1), which contributes to the additional stability of the structure.

Related literature

For general background, see Benson et al. (2000).

S2. Experimental

A suspension of praseodymium oxide (205 mg, 0.20 mmol) in in water (20 ml) was slowly added to a solution of oxalic acid (0.10 mmol) in water (10 ml). The resultant mixture was sealed in a 50 cm³ stainless steel reactor with Teflon liner and kept under autogenous pressure at 100 ° for 78 h, and then cooled to room temperature at a rate of 0.5 °. min^-1. Colorless block crystals of the compound suited for single-crystal X-ray diffraction analyses formed with a yield of approximate 65%. The assigned structure was substantiated by elemental analysis; calculated for C₃H₆O₉Pr: C 11.01, H 1.83%; found: C 10.96, H 1.95%.

S3. Refinement

The structure was solved using direct methods followed by Fourier synthesis. Non-H atoms were refined anisotropically. The water H atoms were located in a difference Fourier map, and were refined with distance restraints of O—H = 0.84(0.01) and H···H 1.428 (0.002) |%A, but their U_iso values were set equal to 1.5 U_eq(parent atom O).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); 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

	Fig. 1. The structure of the title compound (I) with 30% probability ellipsoids. Symmetry code a: 1 - x,-y,1 - z; b: -x,-1/2 + y,0.5 - z; c: -x,-y,1 - z; d: x,0.5 - y,1/2 + z.
	Fig. 2. A view of one-dimensional chain constructed by hydrogen bonding interactions. Symmetry code a: x - 1,y,z.

Poly[[tetraaquadi-µ₃-oxalato-µ₂-oxalato-diprasedymium(III)] dihydrate]

Crystal data

[Pr2(C2O4)3(H2O)4]·2H2O	F(000) = 620
Mr = 653.98	Dx = 2.639 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.8834 (5) Å	Cell parameters from 3328 reflections
b = 8.2811 (4) Å	θ = 3.2–28.6°
c = 10.1818 (5) Å	µ = 5.95 mm^−1
β = 99.053 (1)°	T = 298 K
V = 822.95 (7) Å^3	Block, yellow
Z = 2	0.26 × 0.22 × 0.16 mm

Data collection

Bruker SMART diffractometer	1487 independent reflections
Radiation source: fine-focus sealed tube	1397 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ϕ and ω scans	θmax = 25.3°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −11→11
Tmin = 0.307, Tmax = 0.450	k = −9→9
4111 measured reflections	l = −12→7

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.016	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.035	w = 1/[σ^2(Fo^2) + (0.0087P)^2 + 0.7364P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.007
1487 reflections	Δρmax = 0.44 e Å^−3
139 parameters	Δρmin = −0.54 e Å^−3
9 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0127 (4)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Pr1	0.185002 (15)	0.098389 (18)	0.437068 (15)	0.01483 (9)
O1	0.0042 (2)	0.3167 (2)	0.4302 (2)	0.0210 (5)
O2	−0.1229 (2)	0.4945 (3)	0.2991 (2)	0.0249 (5)
O3	0.1838 (2)	0.3092 (3)	0.2610 (2)	0.0229 (5)
O4	0.0564 (2)	0.4802 (3)	0.12614 (19)	0.0196 (5)
O5	0.4011 (2)	0.0665 (3)	0.3529 (2)	0.0275 (5)
O6	0.6199 (2)	−0.0090 (3)	0.3924 (2)	0.0287 (5)
O7	0.1928 (2)	−0.2047 (3)	0.4324 (3)	0.0357 (6)
H7A	0.255 (3)	−0.260 (3)	0.406 (4)	0.054*
H7B	0.153 (3)	−0.250 (4)	0.490 (3)	0.054*
O8	0.3072 (3)	0.3550 (3)	0.5421 (2)	0.0296 (5)
H8A	0.252 (3)	0.393 (4)	0.589 (3)	0.044*
O9	0.3963 (3)	0.5983 (3)	0.3724 (3)	0.0353 (6)
H9B	0.393 (4)	0.566 (5)	0.2945 (16)	0.053*
C1	−0.0222 (3)	0.4050 (3)	0.3291 (3)	0.0172 (6)
C2	0.0829 (3)	0.3968 (3)	0.2319 (3)	0.0162 (6)
C3	0.5054 (3)	0.0165 (4)	0.4261 (3)	0.0200 (7)
H8B	0.3907 (13)	0.358 (8)	0.576 (4)	0.13 (3)*
H9A	0.370 (7)	0.534 (5)	0.427 (3)	0.13 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pr1	0.01116 (11)	0.01772 (12)	0.01591 (11)	0.00145 (6)	0.00305 (7)	0.00222 (6)
O1	0.0236 (11)	0.0229 (11)	0.0185 (11)	0.0044 (9)	0.0094 (9)	0.0063 (9)
O2	0.0248 (12)	0.0312 (12)	0.0191 (11)	0.0126 (10)	0.0051 (10)	0.0018 (9)
O3	0.0186 (11)	0.0244 (11)	0.0274 (12)	0.0049 (9)	0.0090 (10)	0.0067 (10)
O4	0.0179 (11)	0.0261 (11)	0.0149 (11)	0.0013 (9)	0.0033 (9)	0.0049 (9)
O5	0.0183 (12)	0.0451 (14)	0.0198 (12)	0.0077 (10)	0.0052 (10)	0.0090 (10)
O6	0.0195 (12)	0.0478 (14)	0.0204 (12)	0.0121 (10)	0.0078 (10)	0.0095 (11)
O7	0.0351 (14)	0.0252 (13)	0.0533 (17)	0.0080 (11)	0.0273 (13)	0.0110 (11)
O8	0.0303 (14)	0.0317 (13)	0.0272 (13)	−0.0058 (11)	0.0057 (11)	−0.0034 (10)
O9	0.0397 (15)	0.0410 (15)	0.0274 (14)	0.0031 (12)	0.0118 (13)	−0.0034 (12)
C1	0.0182 (16)	0.0162 (14)	0.0170 (15)	−0.0001 (12)	0.0023 (13)	−0.0043 (12)
C2	0.0188 (16)	0.0156 (14)	0.0141 (15)	−0.0066 (12)	0.0022 (12)	−0.0034 (12)
C3	0.0170 (16)	0.0257 (16)	0.0183 (16)	0.0030 (13)	0.0064 (13)	0.0042 (13)

Geometric parameters (Å, º)

Pr1—O5	2.438 (2)	O4—Pr1^v	2.552 (2)
Pr1—O6^i	2.495 (2)	O4—Pr1^iv	2.566 (2)
Pr1—O3	2.501 (2)	O5—C3	1.244 (4)
Pr1—O7	2.512 (2)	O6—C3	1.251 (4)
Pr1—O1	2.535 (2)	O6—Pr1^i	2.495 (2)
Pr1—O2^ii	2.537 (2)	O7—H7A	0.847 (10)
Pr1—O4^iii	2.552 (2)	O7—H7B	0.845 (10)
Pr1—O4^ii	2.566 (2)	O8—H8A	0.842 (10)
Pr1—O8	2.590 (2)	O8—H8B	0.844 (10)
O1—C1	1.257 (4)	O9—H9B	0.832 (10)
O2—C1	1.240 (4)	O9—H9A	0.839 (10)
O2—Pr1^iv	2.537 (2)	C1—C2	1.545 (4)
O3—C2	1.231 (4)	C3—C3^i	1.549 (6)
O4—C2	1.271 (4)
O5—Pr1—O6^i	65.72 (7)	O3—Pr1—O8	70.89 (8)
O5—Pr1—O3	74.28 (7)	O7—Pr1—O8	144.46 (8)
O6^i—Pr1—O3	128.45 (7)	O1—Pr1—O8	72.97 (8)
O5—Pr1—O7	81.61 (7)	O2^ii—Pr1—O8	134.18 (7)
O6^i—Pr1—O7	72.19 (8)	O4^iii—Pr1—O8	98.79 (7)
O3—Pr1—O7	132.90 (8)	O4^ii—Pr1—O8	140.47 (7)
O5—Pr1—O1	136.09 (7)	C1—O1—Pr1	119.53 (18)
O6^i—Pr1—O1	134.01 (7)	C1—O2—Pr1^iv	120.07 (19)
O3—Pr1—O1	63.82 (6)	C2—O3—Pr1	119.75 (18)
O7—Pr1—O1	137.35 (7)	C2—O4—Pr1^v	116.09 (18)
O5—Pr1—O2^ii	74.00 (7)	C2—O4—Pr1^iv	118.63 (18)
O6^i—Pr1—O2^ii	127.17 (7)	Pr1^v—O4—Pr1^iv	117.51 (8)
O3—Pr1—O2^ii	65.42 (7)	C3—O5—Pr1	120.94 (18)
O7—Pr1—O2^ii	69.33 (8)	C3—O6—Pr1^i	119.5 (2)
O1—Pr1—O2^ii	98.71 (7)	Pr1—O7—H7A	125 (2)
O5—Pr1—O4^iii	143.64 (7)	Pr1—O7—H7B	114 (2)
O6^i—Pr1—O4^iii	79.71 (7)	H7A—O7—H7B	115.0 (15)
O3—Pr1—O4^iii	140.53 (7)	Pr1—O8—H8A	104 (2)
O7—Pr1—O4^iii	77.27 (7)	Pr1—O8—H8B	124 (4)
O1—Pr1—O4^iii	76.71 (6)	H8A—O8—H8B	115.7 (15)
O2^ii—Pr1—O4^iii	123.63 (6)	H9B—O9—H9A	117.4 (16)
O5—Pr1—O4^ii	134.60 (7)	O2—C1—O1	127.3 (3)
O6^i—Pr1—O4^ii	130.37 (7)	O2—C1—C2	117.6 (3)
O3—Pr1—O4^ii	100.79 (7)	O1—C1—C2	115.1 (3)
O7—Pr1—O4^ii	69.15 (7)	O3—C2—O4	125.1 (3)
O1—Pr1—O4^ii	68.99 (7)	O3—C2—C1	118.2 (3)
O2^ii—Pr1—O4^ii	63.66 (6)	O4—C2—C1	116.7 (3)
O4^iii—Pr1—O4^ii	62.49 (8)	O5—C3—O6	126.3 (3)
O5—Pr1—O8	81.77 (8)	O5—C3—C3^i	117.6 (3)
O6^i—Pr1—O8	72.37 (8)	O6—C3—C3^i	116.1 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O7—H7A···O9^vi	0.85 (1)	1.89 (1)	2.732 (3)	171 (3)
O7—H7B···O1^vii	0.85 (1)	1.94 (2)	2.732 (3)	155 (4)
O8—H8A···O2^viii	0.84 (1)	2.06 (1)	2.900 (3)	175 (4)
O8—H8A···O3^iii	0.84 (1)	2.59 (4)	3.026 (3)	114 (3)
O8—H8B···O9^ix	0.84 (1)	2.12 (2)	2.949 (4)	167 (6)
O9—H9B···O6^x	0.83 (1)	1.99 (1)	2.820 (3)	178 (4)
O9—H9A···O8	0.84 (1)	2.05 (1)	2.881 (4)	173 (4)

Symmetry codes: (iii) x, −y+1/2, z+1/2; (vi) x, y−1, z; (vii) −x, −y, −z+1; (viii) −x, −y+1, −z+1; (ix) −x+1, −y+1, −z+1; (x) −x+1, y+1/2, −z+1/2.