metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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Poly[tetra­aqua­(μ8-butane-1,2,3,4-tetra­carboxyl­ato)distrontium]

aDepartment of Chemistry, R&D Center for Membrane Technology, Center for Nanotechnology, Chung-Yuan Christian University, Chung-Li 320, Taiwan, and bDepartment of Chemistry, Chung-Yuan Christian University, Chung-Li 320, Taiwan
*Correspondence e-mail: chiaher@cycu.edu.tw

(Received 28 October 2011; accepted 2 November 2011; online 5 November 2011)

In the title compound, [Sr2(C8H6O8)(H2O)4)]n, the SrII ion is coordinated by six O atoms of four symmetry-related ligands and two water mol­ecules in a distorted bicapped trigonal–prismatic environment. The butane-1,2,3,4-tetra­carboxyl­ate ligands lie on inversion centers and bridge SrII ions, forming a three-dimensional network. Within the three-dimensional structure, there are O—H⋯O hydrogen bonds involving the water mol­ecules and carboxyl­ate O atoms.

Related literature

For general background to coordination polymers, see: Jiang & Xu (2011[Jiang, H.-L. & Xu, Q. (2011). Chem. Commun. 47, 3351-3370.]); Kam et al. (2007[Kam, K. C., Young, K. L. M. & Cheetham, A. K. (2007). Cryst. Growth Des. 7, 1522-1532.]); Kitagawa et al. (2004[Kitagawa, S., Kitaura, R. & Noro, S. (2004). Angew. Chem. Int. Ed. 43, 2334-2375.]); Liu et al. (2009[Liu, H. K., Tsao, T. H., Zhang, Y. T. & Lin, C. H. (2009). CrystEngComm, 11, 1462-1468.]). For related structures, see: Ma & Yan (2009[Ma, C.-H. & Yan, Y.-S. (2009). Acta Cryst. E65, m1555.]); Wu (2009[Wu, L. (2009). Acta Cryst. E65, m1425.]).

[Scheme 1]

Experimental

Crystal data
  • [Sr2(C8H6O8)(H2O)4)]

  • Mr = 477.44

  • Monoclinic, P 21 /n

  • a = 8.7085 (4) Å

  • b = 7.9671 (4) Å

  • c = 10.0697 (4) Å

  • β = 95.409 (2)°

  • V = 695.54 (5) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 7.73 mm−1

  • T = 296 K

  • 0.25 × 0.15 × 0.13 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.248, Tmax = 0.433

  • 7782 measured reflections

  • 1746 independent reflections

  • 1443 reflections with I > 2σ(I)

  • Rint = 0.072

Refinement
  • R[F2 > 2σ(F2)] = 0.028

  • wR(F2) = 0.061

  • S = 0.97

  • 1746 reflections

  • 100 parameters

  • H-atom parameters constrained

  • Δρmax = 0.58 e Å−3

  • Δρmin = −0.46 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1W—H1WA⋯O3i 0.85 1.90 2.729 (3) 164.5
O1W—H1WB⋯O4ii 0.85 2.14 2.944 (3) 159.1
O2W—H2WA⋯O4 0.85 2.06 2.841 (3) 153.1
O2W—H2WB⋯O1Wiii 0.88 1.99 2.864 (3) 170.1
Symmetry codes: (i) -x, -y, -z+1; (ii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (iii) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}].

Data collection: APEX2 (Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg, 2010[Brandenburg, K. (2010). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Supporting information


Comment top

Multicarboxylate ligands, are widely used to construct coordination polymers with interesting properties (Kam, et al., 2007; Liu, et al., 2009, Kitagawa et al., 2004; Jiang & Xu, 2011). The butane-1,2,3,4-tetracarboxylato ligand has already been reported in crystal structures (Ma & Yan, 2009; Wu, 2009). In our continuing investigations on metal coordination polymers we report here the structure of a new Sr coordination polymer based on butane-1,2,3,4-tetracarboxylatic acid.

The asymmetric unit of the title compound consists of one strontium, one half carboxylate ligand and two coordinated water molecules (Fig. 1). The stronium is eight coordinated by six O atoms of four symmetry related ligands and two water molecules. The Sr—O distances range from 2.5491 (18) to 2.688 (2) Å. The ligands bridge the neighboring SrII centers forming a three-dimensional framework structure (Fig. 2). The hydrogen bonds involving the water molecules and the carboxylate O atoms further stabilize the three dimensional structure.

Related literature top

For general background to coordination polymers, see: Jiang & Xu (2011); Kam et al. (2007); Kitagawa et al. (2004); Liu et al. (2009). For related structures, see: Ma & Yan (2009); Wu (2009).

Experimental top

Solvothermal reactions were carriedout at 363 K for 2 d in a Teflon-lined acid digestion bomb with an internal volume of 23 ml followed by slow cooling at 6 K/h to room temperature. A single-phase product consisting of colorless crystals of was obtained from a mixture of butane-1,2,3,4-tetracarboxylatic acid (C8H10O8, 0.0468 g, 0.2 mmol), Sr(NO3)2 (0.0847 g, 0.4 mmol), and ethanol(5.0 ml) and H2O (1.0 ml).

Refinement top

H atoms were constrained to ideal geometries, with C—H = 0.96-0.98 Å, O—H = 0.85-0.88Å and Uiso(H) = 1.2Ueq(C);Uiso(H) = 1.5Ueq(O).

Structure description top

Multicarboxylate ligands, are widely used to construct coordination polymers with interesting properties (Kam, et al., 2007; Liu, et al., 2009, Kitagawa et al., 2004; Jiang & Xu, 2011). The butane-1,2,3,4-tetracarboxylato ligand has already been reported in crystal structures (Ma & Yan, 2009; Wu, 2009). In our continuing investigations on metal coordination polymers we report here the structure of a new Sr coordination polymer based on butane-1,2,3,4-tetracarboxylatic acid.

The asymmetric unit of the title compound consists of one strontium, one half carboxylate ligand and two coordinated water molecules (Fig. 1). The stronium is eight coordinated by six O atoms of four symmetry related ligands and two water molecules. The Sr—O distances range from 2.5491 (18) to 2.688 (2) Å. The ligands bridge the neighboring SrII centers forming a three-dimensional framework structure (Fig. 2). The hydrogen bonds involving the water molecules and the carboxylate O atoms further stabilize the three dimensional structure.

For general background to coordination polymers, see: Jiang & Xu (2011); Kam et al. (2007); Kitagawa et al. (2004); Liu et al. (2009). For related structures, see: Ma & Yan (2009); Wu (2009).

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of part of the title structure, showing 50% probability displacement ellipsoids. [symmetry codes: (i) 1 - x, -y, 1 - z; (ii) –x + 1/2, y + 1/2, -z + 1/2; (iii) x - 1/2, -y - 1/2, z + 1/2].
[Figure 2] Fig. 2. Part of the crystal structure of the title compound viewed along the a axis.
Poly[tetraaqua(µ8-butane-1,2,3,4-tetracarboxylato)distrontium] top
Crystal data top
[Sr2(C8H6O8)(H2O)4)]F(000) = 468
Mr = 477.44Dx = 2.280 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 4783 reflections
a = 8.7085 (4) Åθ = 3.0–28.5°
b = 7.9671 (4) ŵ = 7.73 mm1
c = 10.0697 (4) ÅT = 296 K
β = 95.409 (2)°Tabular, colourless
V = 695.54 (5) Å30.25 × 0.15 × 0.13 mm
Z = 2
Data collection top
Bruker APEXII CCD
diffractometer
1746 independent reflections
Radiation source: fine-focus sealed tube1443 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.072
Detector resolution: 8.3333 pixels mm-1θmax = 28.7°, θmin = 3.0°
φ and ω scansh = 1111
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
k = 810
Tmin = 0.248, Tmax = 0.433l = 1313
7782 measured reflections
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)] = 0.028Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.061H-atom parameters constrained
S = 0.97 w = 1/[σ2(Fo2) + (0.0282P)2]
where P = (Fo2 + 2Fc2)/3
1746 reflections(Δ/σ)max = 0.001
100 parametersΔρmax = 0.58 e Å3
0 restraintsΔρmin = 0.46 e Å3
Crystal data top
[Sr2(C8H6O8)(H2O)4)]V = 695.54 (5) Å3
Mr = 477.44Z = 2
Monoclinic, P21/nMo Kα radiation
a = 8.7085 (4) ŵ = 7.73 mm1
b = 7.9671 (4) ÅT = 296 K
c = 10.0697 (4) Å0.25 × 0.15 × 0.13 mm
β = 95.409 (2)°
Data collection top
Bruker APEXII CCD
diffractometer
1746 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
1443 reflections with I > 2σ(I)
Tmin = 0.248, Tmax = 0.433Rint = 0.072
7782 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0280 restraints
wR(F2) = 0.061H-atom parameters constrained
S = 0.97Δρmax = 0.58 e Å3
1746 reflectionsΔρmin = 0.46 e Å3
100 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
Sr10.22086 (2)0.04306 (3)0.60530 (2)0.01806 (9)
O30.2772 (2)0.0137 (3)0.36082 (19)0.0333 (5)
O1W0.0092 (2)0.0561 (3)0.7699 (2)0.0285 (5)
H1WA0.08570.04340.74370.043*
H1WB0.01080.14830.81220.043*
O2W0.4040 (2)0.2833 (3)0.5536 (2)0.0405 (6)
H2WA0.46240.22270.51040.061*
H2WB0.44200.36230.60890.061*
O10.5067 (2)0.3138 (2)0.03110 (18)0.0249 (4)
O20.69087 (19)0.2208 (3)0.17764 (18)0.0249 (4)
O40.5123 (2)0.0870 (3)0.34605 (19)0.0281 (5)
C10.3872 (3)0.0252 (4)0.2949 (2)0.0194 (5)
C20.3645 (3)0.0043 (4)0.1447 (2)0.0202 (6)
H2A0.31070.10130.10750.024*
H2B0.30010.09200.12430.024*
C30.5739 (3)0.1966 (4)0.0963 (2)0.0183 (5)
C40.5134 (3)0.0185 (4)0.0755 (2)0.0174 (5)
H4A0.59140.05970.11560.021*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sr10.01577 (12)0.01900 (17)0.01883 (12)0.00105 (10)0.00146 (8)0.00014 (10)
O30.0215 (9)0.0593 (17)0.0201 (9)0.0077 (9)0.0072 (8)0.0053 (9)
O1W0.0222 (9)0.0352 (14)0.0281 (10)0.0005 (8)0.0025 (8)0.0077 (9)
O2W0.0443 (12)0.0363 (15)0.0418 (12)0.0080 (11)0.0088 (10)0.0065 (11)
O10.0272 (9)0.0188 (12)0.0268 (9)0.0009 (8)0.0074 (8)0.0012 (8)
O20.0249 (9)0.0185 (11)0.0295 (10)0.0031 (8)0.0080 (8)0.0007 (8)
O40.0196 (9)0.0405 (15)0.0237 (9)0.0016 (8)0.0004 (7)0.0038 (9)
C10.0171 (11)0.0219 (16)0.0193 (12)0.0025 (11)0.0027 (9)0.0002 (11)
C20.0157 (11)0.0272 (17)0.0177 (11)0.0007 (10)0.0016 (9)0.0003 (11)
C30.0181 (11)0.0195 (16)0.0176 (11)0.0007 (10)0.0029 (9)0.0026 (10)
C40.0182 (11)0.0195 (16)0.0144 (11)0.0016 (10)0.0016 (9)0.0024 (10)
Geometric parameters (Å, º) top
Sr1—O4i2.5491 (18)O1—Sr1iv2.5689 (17)
Sr1—O1ii2.5690 (17)O1—Sr1v2.6666 (18)
Sr1—O2W2.576 (2)O2—C31.260 (3)
Sr1—O1W2.5946 (19)O2—Sr1i2.6565 (18)
Sr1—O32.5948 (19)O2—Sr1v2.688 (2)
Sr1—O2i2.6565 (18)O4—C11.260 (3)
Sr1—O1iii2.6666 (18)O4—Sr1i2.5492 (18)
Sr1—O2iii2.688 (2)C1—C21.516 (3)
Sr1—C3iii3.040 (3)C2—C41.540 (3)
Sr1—H2WA2.7869C2—H2A0.9615
O3—C11.254 (3)C2—H2B0.9614
O1W—H1WA0.8501C3—C41.521 (4)
O1W—H1WB0.8483C3—Sr1v3.040 (3)
O2W—H2WA0.8499C4—C4vi1.544 (5)
O2W—H2WB0.8836C4—H4A0.9800
O1—C31.254 (3)
O4i—Sr1—O1ii157.86 (6)O4i—Sr1—H2WA64.6
O4i—Sr1—O2W76.72 (7)O1ii—Sr1—H2WA99.1
O1ii—Sr1—O2W91.33 (6)O2W—Sr1—H2WA17.7
O4i—Sr1—O1W125.67 (6)O1W—Sr1—H2WA143.4
O1ii—Sr1—O1W76.42 (6)O3—Sr1—H2WA63.1
O2W—Sr1—O1W126.16 (7)O2i—Sr1—H2WA80.7
O4i—Sr1—O382.01 (6)O1iii—Sr1—H2WA141.8
O1ii—Sr1—O377.02 (6)O2iii—Sr1—H2WA132.8
O2W—Sr1—O376.20 (7)C3iii—Sr1—H2WA141.7
O1W—Sr1—O3145.32 (6)Sr1vii—Sr1—H2WA125.9
O4i—Sr1—O2i82.57 (6)C1—O3—Sr1132.92 (17)
O1ii—Sr1—O2i110.61 (6)Sr1—O1W—H1WA121.7
O2W—Sr1—O2i68.51 (6)Sr1—O1W—H1WB112.2
O1W—Sr1—O2i67.72 (6)H1WA—O1W—H1WB103.2
O3—Sr1—O2i143.85 (6)Sr1—O2W—H2WA95.3
O4i—Sr1—O1iii112.11 (6)Sr1—O2W—H2WB127.1
O1ii—Sr1—O1iii70.75 (7)H2WA—O2W—H2WB121.4
O2W—Sr1—O1iii151.93 (6)C3—O1—Sr1iv155.35 (16)
O1W—Sr1—O1iii71.71 (6)C3—O1—Sr1v94.78 (14)
O3—Sr1—O1iii78.74 (6)Sr1iv—O1—Sr1v109.25 (7)
O2i—Sr1—O1iii137.41 (6)C3—O2—Sr1i127.36 (17)
O4i—Sr1—O2iii70.72 (6)C3—O2—Sr1v93.61 (16)
O1ii—Sr1—O2iii118.62 (5)Sr1i—O2—Sr1v134.76 (7)
O2W—Sr1—O2iii147.38 (6)C1—O4—Sr1i131.09 (19)
O1W—Sr1—O2iii76.83 (6)O3—C1—O4123.7 (2)
O3—Sr1—O2iii97.05 (7)O3—C1—C2117.8 (2)
O2i—Sr1—O2iii108.31 (3)O4—C1—C2118.5 (2)
O1iii—Sr1—O2iii48.59 (5)C1—C2—C4115.4 (2)
O4i—Sr1—C3iii90.58 (7)C1—C2—H2A108.3
O1ii—Sr1—C3iii94.92 (6)C4—C2—H2A108.6
O2W—Sr1—C3iii159.30 (7)C1—C2—H2B108.6
O1W—Sr1—C3iii74.52 (6)C4—C2—H2B108.0
O3—Sr1—C3iii86.00 (7)H2A—C2—H2B107.8
O2i—Sr1—C3iii126.65 (6)O1—C3—O2122.4 (2)
O1iii—Sr1—C3iii24.28 (6)O1—C3—C4118.9 (2)
O2iii—Sr1—C3iii24.44 (6)O2—C3—C4118.7 (2)
O4i—Sr1—Sr1vii142.42 (5)O1—C3—Sr1v60.94 (13)
O1ii—Sr1—Sr1vii36.13 (4)O2—C3—Sr1v61.95 (14)
O2W—Sr1—Sr1vii124.41 (5)C4—C3—Sr1v172.02 (16)
O1W—Sr1—Sr1vii70.29 (4)C3—C4—C2110.1 (2)
O3—Sr1—Sr1vii75.10 (4)C3—C4—C4vi109.4 (3)
O2i—Sr1—Sr1vii132.19 (4)C2—C4—C4vi111.5 (2)
O1iii—Sr1—Sr1vii34.62 (4)C3—C4—H4A108.6
O2iii—Sr1—Sr1vii82.83 (3)C2—C4—H4A108.6
C3iii—Sr1—Sr1vii58.82 (5)C4vi—C4—H4A108.6
Symmetry codes: (i) x+1, y, z+1; (ii) x+1/2, y+1/2, z+1/2; (iii) x1/2, y1/2, z+1/2; (iv) x+1/2, y1/2, z+1/2; (v) x+1/2, y1/2, z1/2; (vi) x+1, y, z; (vii) x, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1WA···O3vii0.851.902.729 (3)164.5
O1W—H1WB···O4viii0.852.142.944 (3)159.1
O2W—H2WA···O40.852.062.841 (3)153.1
O2W—H2WB···O1Wix0.881.992.864 (3)170.1
Symmetry codes: (vii) x, y, z+1; (viii) x1/2, y+1/2, z+1/2; (ix) x+1/2, y+1/2, z+3/2.

Experimental details

Crystal data
Chemical formula[Sr2(C8H6O8)(H2O)4)]
Mr477.44
Crystal system, space groupMonoclinic, P21/n
Temperature (K)296
a, b, c (Å)8.7085 (4), 7.9671 (4), 10.0697 (4)
β (°) 95.409 (2)
V3)695.54 (5)
Z2
Radiation typeMo Kα
µ (mm1)7.73
Crystal size (mm)0.25 × 0.15 × 0.13
Data collection
DiffractometerBruker APEXII CCD
Absorption correctionMulti-scan
(SADABS; Bruker, 2010)
Tmin, Tmax0.248, 0.433
No. of measured, independent and
observed [I > 2σ(I)] reflections
7782, 1746, 1443
Rint0.072
(sin θ/λ)max1)0.676
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.028, 0.061, 0.97
No. of reflections1746
No. of parameters100
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.58, 0.46

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2010), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1WA···O3i0.851.902.729 (3)164.5
O1W—H1WB···O4ii0.852.142.944 (3)159.1
O2W—H2WA···O40.852.062.841 (3)153.1
O2W—H2WB···O1Wiii0.881.992.864 (3)170.1
Symmetry codes: (i) x, y, z+1; (ii) x1/2, y+1/2, z+1/2; (iii) x+1/2, y+1/2, z+3/2.
 

Acknowledgements

This research was supported by the National Science Council, Taiwan (NSC99–2113-M-033–005-MY2) and by the Center-of-Excellence (COE) Program on Membrane Technology from the Ministry of Education (MOE).

References

First citationBrandenburg, K. (2010). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationBruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationJiang, H.-L. & Xu, Q. (2011). Chem. Commun. 47, 3351–3370.  Web of Science CrossRef CAS Google Scholar
First citationKam, K. C., Young, K. L. M. & Cheetham, A. K. (2007). Cryst. Growth Des. 7, 1522–1532.  Web of Science CSD CrossRef CAS Google Scholar
First citationKitagawa, S., Kitaura, R. & Noro, S. (2004). Angew. Chem. Int. Ed. 43, 2334–2375.  Web of Science CrossRef CAS Google Scholar
First citationLiu, H. K., Tsao, T. H., Zhang, Y. T. & Lin, C. H. (2009). CrystEngComm, 11, 1462–1468.  Web of Science CSD CrossRef CAS Google Scholar
First citationMa, C.-H. & Yan, Y.-S. (2009). Acta Cryst. E65, m1555.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWu, L. (2009). Acta Cryst. E65, m1425.  Web of Science CrossRef IUCr Journals Google Scholar

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