Poly[[diaqua­tris[μ₄-(p-phenyl­enedi­oxy)­diacetato]dipraseodymium(III)] dihydrate]

The title praseodymium coordination polymer, {[Pr₂(C₁₀H₈O₆)₃(H₂O)₂]·2H₂O}_n, was obtained by the hydro­thermal reaction of Pr(NO₃)₃ with (p-phenyl­enedi­oxy)diacetic acid in alkaline aqueous solution. Each Pr^III atom is coordinated by nine O atoms, eight from four (p-phenyl­enedi­oxy)diacetate ligands and one from a water mol­ecule, displaying a tricapped trigonal prismatic geometry. There is a centre of symmetry at the mid-point of the Pr...Pr vector. The bridging ligands crosslink the metal ions to form a three-dimensional network, with channels running along the c axis in which the uncoordinated water mol­ecules are located. The crystal structure is stabilized by inter­molecular O—H...O hydrogen-bonding inter­actions.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.030
• wR factor = 0.073
• Data-to-parameter ratio = 17.1

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT417_ALERT_2_B Short Inter D-H..H-D       H2W    ..  H4W     ..       1.94 Ang.
PLAT420_ALERT_2_B D-H Without Acceptor       O1W    -   H2W    ...          ?

Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       2.00 Ratio
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         O1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Pr1
PLAT245_ALERT_2_C U(iso) H1W     Smaller than U(eq) O1W     by ...       0.03 AngSq
PLAT245_ALERT_2_C U(iso) H2W     Smaller than U(eq) O1W     by ...       0.03 AngSq
PLAT245_ALERT_2_C U(iso) H3W     Smaller than U(eq) O2W     by ...       0.04 AngSq
PLAT245_ALERT_2_C U(iso) H4W     Smaller than U(eq) O2W     by ...       0.04 AngSq
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.15 Ratio

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT794_ALERT_5_G Check Predicted Bond Valency for Pr1         (3)       3.16
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          6

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

   5 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   8 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

Molecular self-assembly of supramolecular architectures has received much attention during recent decades (Tao et al., 2000; Choi & Jeon, 2003). The structures and properties of such systems depend on the coordination and geometric preferences of both the central metal ions and the bridging building blocks, as well as on the influence of weaker non-covalent interactions, such as hydrogen bonds and π-π stacking interactions. As a building block, (p-phenylenedioxy)diacetic acid (1,4-BDOA) is an excellent candidate for the construction of supramolecular complexes (Qiu et al., 2006). Recently, we obtained the title novel coordination polymer, (I), by the reaction of praseodymium nitrate, (p-phenylenedioxy)diacetic acid in alkaline aqueous solution, and its crystal structure is reported here.

In (I), each Pr^III ion is coordinated by nine oxygen atoms, eight from four 1,4-BDOA^2- ligands and one from a water molecule (Fig. 1). The coordination environment around the Pr^III ion can be described as a tri-capped-trigonal prismatic geometry with O—Pr—O bond angles ranging from 47.76 (8) to 149.67 (8) Å. Pairs of Pr ions are bridged by the dianionic ligands at a distance of 4.188 (3) Å to form helical chains which are further cross-linked by the ligands into a three-dimensional supramolecular network (Fig. 2) with channels running along the c axis hosting the uncoordinated water molecules. The crystal structure is stabilized by intermolecular O—H···O hydrogen bonding interactions.

Related literature

For related literature, see: Choi & Jeon (2003); Qiu et al. (2006); Tao et al. (2000).

S2. Experimental

A mixture of Pr(NO₃)₃ (0.5 mmol), (p-phenylenedioxy)diacetic acid (0.75 mmol), NaOH (1.5 mmol) and H₂O (10 ml) was placed in a 20 ml Teflon reactor, which was heated at 433 K for three days and then cooled to room temperature at a rate of 10 K h^-1. Crystals were obtained after washing with water and drying in air.

S3. Refinement

Carbon-bound H atoms were placed at calculated positions and were treated as riding on the parent C atoms with C—H = 0.93 Å, and with U_iso(H) = 1.2 U_eq(C). Water H atoms were tentatively located in difference Fourier maps and were refined with distance restraints of O–H = 0.82 or 0.85 Å and H···H = 1.29 or 1.39 Å, each within a standard deviation of 0.01 Å.

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; 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.

Figures

	Fig. 1. The molecular structure of (I), showing the atomic-numbering scheme and displacement ellipsoids drawn at the 50% probability level. Unlabelled atoms are related to the labelled atoms by the symmetry operator (1 - x, -y, 2 - z).
	Fig. 2. The molecular packing of (I), showing the intermolecular hydrogen bonding interactions as the broken lines.

Poly[[diaquatris[µ₄-(p-phenylenedioxy)diacetato]dipraseodymium(III)] dihydrate]

Crystal data

[Pr2(C10H8O6)3(H2O)2]·2H2O	F(000) = 1012
Mr = 1026.38	Dx = 1.959 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3500 reflections
a = 12.1685 (3) Å	θ = 1.7–28.0°
b = 16.9339 (4) Å	µ = 2.86 mm^−1
c = 8.9299 (2) Å	T = 293 K
β = 108.956 (1)°	Block, colourless
V = 1740.30 (7) Å^3	0.18 × 0.15 × 0.12 mm
Z = 2

Data collection

Bruker APEXII area-detector diffractometer	4182 independent reflections
Radiation source: fine-focus sealed tube	3381 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
φ and ω scans	θmax = 28.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −16→16
Tmin = 0.607, Tmax = 0.715	k = −17→22
14677 measured reflections	l = −11→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.073	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0304P)^2 + 2.8471P] where P = (Fo^2 + 2Fc^2)/3
4182 reflections	(Δ/σ)max = 0.001
244 parameters	Δρmax = 0.62 e Å^−3
6 restraints	Δρmin = −0.81 e Å^−3

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
C1	0.3882 (3)	0.2982 (2)	1.0544 (4)	0.0214 (7)
C2	0.2921 (3)	0.2998 (2)	0.8969 (4)	0.0230 (8)
H2A	0.2219	0.3214	0.9097	0.028*
H2B	0.3144	0.3329	0.8229	0.028*
C3	0.1633 (3)	0.2069 (2)	0.7228 (4)	0.0198 (7)
C4	0.1125 (3)	0.2595 (2)	0.6019 (5)	0.0274 (8)
H4	0.1479	0.3077	0.5967	0.033*
C5	0.0081 (3)	0.2397 (2)	0.4888 (5)	0.0289 (9)
H5	−0.0268	0.2749	0.4075	0.035*
C6	−0.0447 (3)	0.1683 (2)	0.4949 (4)	0.0218 (8)
C7	0.0062 (3)	0.1167 (2)	0.6184 (4)	0.0262 (8)
H7	−0.0295	0.0687	0.6244	0.031*
C8	0.1099 (3)	0.1363 (2)	0.7325 (4)	0.0240 (8)
H8	0.1437	0.1019	0.8159	0.029*
C9	−0.1944 (3)	0.0758 (2)	0.3755 (4)	0.0270 (8)
H9A	−0.2151	0.0695	0.4709	0.032*
H9B	−0.1353	0.0369	0.3781	0.032*
C10	−0.3006 (3)	0.0605 (2)	0.2326 (4)	0.0227 (8)
C11	0.3538 (3)	0.0272 (2)	1.1574 (4)	0.0254 (8)
C12	0.3027 (4)	−0.0132 (3)	1.2703 (5)	0.0414 (11)
H12A	0.2934	−0.0690	1.2443	0.050*
H12B	0.3569	−0.0086	1.3770	0.050*
C13	0.1003 (4)	0.0075 (3)	1.1304 (5)	0.0352 (10)
C14	0.0010 (4)	0.0502 (3)	1.1204 (5)	0.0368 (10)
H14	0.0016	0.0842	1.2024	0.044*
C15	0.0980 (4)	−0.0433 (3)	1.0079 (5)	0.0377 (10)
H15	0.1636	−0.0727	1.0126	0.045*
O1	0.4518 (3)	0.23847 (17)	1.0882 (3)	0.0385 (8)
O2	0.3992 (2)	0.35833 (16)	1.1385 (3)	0.0284 (6)
O3	0.2716 (2)	0.22057 (15)	0.8373 (3)	0.0241 (6)
O4	−0.1475 (2)	0.15296 (16)	0.3742 (3)	0.0272 (6)
O5	−0.3176 (2)	−0.01103 (16)	0.2027 (3)	0.0281 (6)
O6	−0.3610 (2)	0.11699 (16)	0.1607 (3)	0.0312 (6)
O7	0.3150 (2)	0.09148 (16)	1.0965 (3)	0.0318 (6)
O8	0.4394 (2)	−0.00571 (16)	1.1333 (3)	0.0282 (6)
O9	0.1936 (3)	0.0180 (2)	1.2671 (3)	0.0414 (8)
O1W	0.6001 (3)	0.2096 (2)	0.8741 (4)	0.0525 (10)
O2W	0.7480 (3)	0.2822 (2)	0.1433 (4)	0.0648 (11)
Pr1	0.451486 (16)	0.116370 (11)	0.92970 (2)	0.01832 (7)
H1W	0.6202	0.2263	0.7986	0.022*
H2W	0.5562	0.2409	0.8926	0.022*
H3W	0.7894	0.2456	0.1300	0.022*
H4W	0.6805	0.2807	0.0727	0.022*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0247 (19)	0.019 (2)	0.0184 (16)	0.0007 (15)	0.0038 (14)	0.0004 (15)
C2	0.027 (2)	0.0151 (19)	0.0206 (17)	−0.0004 (15)	−0.0008 (15)	−0.0047 (14)
C3	0.0137 (16)	0.0204 (19)	0.0200 (16)	0.0001 (14)	−0.0021 (13)	−0.0060 (14)
C4	0.023 (2)	0.021 (2)	0.031 (2)	−0.0068 (16)	−0.0009 (16)	0.0024 (16)
C5	0.023 (2)	0.026 (2)	0.0268 (19)	−0.0029 (17)	−0.0073 (16)	0.0071 (16)
C6	0.0156 (17)	0.022 (2)	0.0199 (16)	−0.0023 (15)	−0.0047 (13)	−0.0043 (15)
C7	0.0225 (19)	0.023 (2)	0.0248 (18)	−0.0062 (16)	−0.0034 (15)	0.0009 (16)
C8	0.0203 (18)	0.022 (2)	0.0217 (17)	−0.0001 (15)	−0.0038 (14)	0.0033 (15)
C9	0.0236 (19)	0.020 (2)	0.0262 (19)	−0.0056 (16)	−0.0076 (15)	0.0021 (16)
C10	0.0204 (18)	0.025 (2)	0.0185 (17)	−0.0065 (16)	0.0009 (14)	0.0007 (15)
C11	0.0240 (19)	0.027 (2)	0.0238 (18)	−0.0021 (16)	0.0052 (15)	−0.0027 (16)
C12	0.040 (3)	0.044 (3)	0.042 (2)	0.001 (2)	0.016 (2)	0.018 (2)
C13	0.037 (2)	0.033 (3)	0.043 (2)	−0.007 (2)	0.024 (2)	0.005 (2)
C14	0.042 (3)	0.031 (2)	0.047 (3)	−0.007 (2)	0.028 (2)	−0.007 (2)
C15	0.036 (2)	0.031 (3)	0.056 (3)	0.0017 (19)	0.028 (2)	0.002 (2)
O1	0.0356 (17)	0.0254 (17)	0.0343 (16)	0.0095 (13)	−0.0166 (13)	−0.0140 (13)
O2	0.0379 (16)	0.0199 (15)	0.0197 (12)	0.0014 (12)	−0.0012 (11)	−0.0079 (11)
O3	0.0192 (13)	0.0168 (14)	0.0249 (13)	−0.0007 (10)	−0.0084 (10)	−0.0051 (10)
O4	0.0201 (13)	0.0207 (15)	0.0271 (13)	−0.0082 (11)	−0.0110 (11)	0.0041 (11)
O5	0.0237 (14)	0.0196 (15)	0.0321 (14)	−0.0063 (11)	−0.0032 (12)	−0.0030 (11)
O6	0.0239 (14)	0.0246 (16)	0.0300 (14)	−0.0006 (12)	−0.0122 (12)	0.0044 (12)
O7	0.0388 (16)	0.0234 (15)	0.0392 (16)	0.0103 (13)	0.0208 (13)	0.0093 (13)
O8	0.0252 (14)	0.0282 (16)	0.0279 (14)	0.0072 (12)	0.0039 (12)	0.0005 (12)
O9	0.0360 (17)	0.055 (2)	0.0406 (17)	−0.0066 (15)	0.0231 (15)	0.0001 (15)
O1W	0.050 (2)	0.065 (3)	0.0345 (17)	−0.0256 (18)	0.0027 (15)	0.0144 (16)
O2W	0.053 (2)	0.067 (3)	0.056 (2)	−0.012 (2)	−0.0079 (18)	0.011 (2)
Pr1	0.01760 (11)	0.01524 (11)	0.01758 (10)	−0.00029 (8)	−0.00054 (7)	0.00020 (8)

Geometric parameters (Å, º)

C1—O2	1.246 (4)	C12—H12A	0.9700
C1—O1	1.250 (4)	C12—H12B	0.9700
C1—C2	1.509 (5)	C13—O9	1.383 (5)
C2—O3	1.435 (4)	C13—C15	1.385 (6)
C2—H2A	0.9700	C13—C14	1.385 (6)
C2—H2B	0.9700	C14—C15^i	1.372 (6)
C3—C8	1.377 (5)	C14—H14	0.9300
C3—C4	1.382 (5)	C15—C14^i	1.372 (6)
C3—O3	1.400 (4)	C15—H15	0.9300
C4—C5	1.382 (5)	O1—Pr1	2.505 (3)
C4—H4	0.9300	O2—Pr1^ii	2.505 (2)
C5—C6	1.378 (5)	O3—Pr1	2.723 (2)
C5—H5	0.9300	O5—Pr1^iii	2.446 (3)
C6—O4	1.385 (4)	O6—Pr1^iv	2.531 (3)
C6—C7	1.386 (5)	O7—Pr1	2.600 (3)
C7—C8	1.380 (5)	O8—Pr1^v	2.465 (3)
C7—H7	0.9300	O8—Pr1	2.788 (3)
C8—H8	0.9300	O1W—Pr1	2.568 (3)
C9—O4	1.427 (4)	O1W—H1W	0.8374
C9—C10	1.514 (5)	O1W—H2W	0.8059
C9—H9A	0.9700	O2W—H3W	0.8319
C9—H9B	0.9700	O2W—H4W	0.8582
C10—O5	1.244 (4)	Pr1—O5^iii	2.446 (3)
C10—O6	1.249 (4)	Pr1—O8^v	2.465 (3)
C11—O7	1.241 (5)	Pr1—O2^vi	2.505 (2)
C11—O8	1.260 (4)	Pr1—O6^vii	2.531 (3)
C11—C12	1.510 (5)	Pr1—H2W	2.5404
C12—O9	1.420 (5)
O2—C1—O1	125.3 (3)	C2—O3—Pr1	117.86 (19)
O2—C1—C2	116.5 (3)	C6—O4—C9	115.3 (3)
O1—C1—C2	118.1 (3)	C10—O5—Pr1^iii	148.5 (2)
O3—C2—C1	108.5 (3)	C10—O6—Pr1^iv	129.8 (2)
O3—C2—H2A	110.0	C11—O7—Pr1	99.8 (2)
C1—C2—H2A	110.0	C11—O8—Pr1^v	155.7 (3)
O3—C2—H2B	110.0	C11—O8—Pr1	90.3 (2)
C1—C2—H2B	110.0	Pr1^v—O8—Pr1	105.58 (9)
H2A—C2—H2B	108.4	C13—O9—C12	117.6 (3)
C8—C3—C4	120.6 (3)	Pr1—O1W—H1W	140.5
C8—C3—O3	116.7 (3)	Pr1—O1W—H2W	79.0
C4—C3—O3	122.7 (3)	H1W—O1W—H2W	109.3
C3—C4—C5	119.0 (4)	H3W—O2W—H4W	110.7
C3—C4—H4	120.5	O5^iii—Pr1—O8^v	70.05 (9)
C5—C4—H4	120.5	O5^iii—Pr1—O1	138.91 (10)
C6—C5—C4	120.9 (3)	O8^v—Pr1—O1	148.69 (9)
C6—C5—H5	119.5	O5^iii—Pr1—O2^vi	73.65 (9)
C4—C5—H5	119.5	O8^v—Pr1—O2^vi	82.36 (9)
C5—C6—O4	116.7 (3)	O1—Pr1—O2^vi	113.49 (9)
C5—C6—C7	119.4 (3)	O5^iii—Pr1—O6^vii	132.82 (9)
O4—C6—C7	123.9 (3)	O8^v—Pr1—O6^vii	77.26 (9)
C8—C7—C6	120.0 (4)	O1—Pr1—O6^vii	72.56 (9)
C8—C7—H7	120.0	O2^vi—Pr1—O6^vii	134.67 (10)
C6—C7—H7	120.0	O5^iii—Pr1—O1W	139.07 (10)
C3—C8—C7	120.0 (3)	O8^v—Pr1—O1W	87.60 (11)
C3—C8—H8	120.0	O1—Pr1—O1W	74.31 (12)
C7—C8—H8	120.0	O2^vi—Pr1—O1W	69.60 (9)
O4—C9—C10	112.6 (3)	O6^vii—Pr1—O1W	69.51 (10)
O4—C9—H9A	109.1	O5^iii—Pr1—O7	73.11 (9)
C10—C9—H9A	109.1	O8^v—Pr1—O7	119.94 (9)
O4—C9—H9B	109.1	O1—Pr1—O7	72.20 (10)
C10—C9—H9B	109.1	O2^vi—Pr1—O7	128.92 (9)
H9A—C9—H9B	107.8	O6^vii—Pr1—O7	96.22 (9)
O5—C10—O6	127.3 (3)	O1W—Pr1—O7	146.24 (11)
O5—C10—C9	112.6 (3)	O5^iii—Pr1—O3	88.99 (8)
O6—C10—C9	120.0 (3)	O8^v—Pr1—O3	149.67 (8)
O7—C11—O8	122.1 (4)	O1—Pr1—O3	59.33 (8)
O7—C11—C12	120.6 (4)	O2^vi—Pr1—O3	70.52 (8)
O8—C11—C12	117.2 (4)	O6^vii—Pr1—O3	131.89 (8)
O9—C12—C11	113.8 (4)	O1W—Pr1—O3	95.18 (10)
O9—C12—H12A	108.8	O7—Pr1—O3	71.23 (8)
C11—C12—H12A	108.8	O5^iii—Pr1—O8	66.83 (8)
O9—C12—H12B	108.8	O8^v—Pr1—O8	74.42 (9)
C11—C12—H12B	108.8	O1—Pr1—O8	103.55 (9)
H12A—C12—H12B	107.7	O2^vi—Pr1—O8	138.96 (8)
O9—C13—C15	125.3 (4)	O6^vii—Pr1—O8	72.30 (8)
O9—C13—C14	116.0 (4)	O1W—Pr1—O8	140.50 (9)
C15—C13—C14	118.7 (4)	O7—Pr1—O8	47.76 (8)
C15^i—C14—C13	121.4 (4)	O3—Pr1—O8	118.08 (8)
C15^i—C14—H14	119.3	O5^iii—Pr1—H2W	145.7
C13—C14—H14	119.3	O8^v—Pr1—H2W	105.7
C14^i—C15—C13	119.9 (4)	O1—Pr1—H2W	58.7
C14^i—C15—H15	120.1	O2^vi—Pr1—H2W	72.0
C13—C15—H15	120.1	O6^vii—Pr1—H2W	75.2
C1—O1—Pr1	130.1 (2)	O1W—Pr1—H2W	18.1
C1—O2—Pr1^ii	135.0 (2)	O7—Pr1—H2W	130.5
C3—O3—C2	115.8 (3)	O3—Pr1—H2W	79.1
C3—O3—Pr1	126.0 (2)	O8—Pr1—H2W	146.6

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W···O2W^ii	0.84	2.40	3.149 (5)	149
O1W—H2W···O1	0.81	2.47	3.064 (5)	131
O2W—H3W···O4^viii	0.83	2.59	2.992 (5)	111
O2W—H4W···O1W^ix	0.86	2.10	2.778 (5)	135

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