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Crystal structure of poly[[hexa­aqua­tris­­(μ-3,6-di­oxo­cyclo­hexa-1,4-diene-1,4-diolato)dierbium(III)] octa­deca­hydrate]

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aMaterials and Textile Technology, Faculty of Science and Technology, Thammasat University, Khlong Luang, Pathum Thani 12121, Thailand, and bDivision of Chemistry, Faculty of Science and Technology, Thammasat University, Khlong Luang, Pathum Thani 12121, Thailand
*Correspondence e-mail: kc@tu.ac.th

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 19 November 2018; accepted 11 December 2018; online 1 January 2019)

The title lanthanide complex, [Er2(C6H2O4)3(H2O)6]·18H2O, is isostructural with its La, Gd, Yb and Lu analogues. The Er3+ ion, located on a threefold rotation axis, is nine-coordinated in a distorted tricapped trigonal–prismatic geometry, which is completed by six oxygen atoms from three dhbq2− ligands and three oxygen atoms from coordinated water mol­ecules. Each dhbq2− ligand acts in a μ2-bis­(bidentate) bridging mode to connect two Er3+ ions to form honeycomb (6,3) two-dimensional sheets extending in the ab plane, having an Er⋯Er separation of 8.7261 (2) Å. In the crystal, extensive O—H⋯O hydrogen-bonding inter­actions involving the coordinated water mol­ecules and the water mol­ecules of crystallization, as well as the oxygen atoms of the dhbq2− ligands, generate an overall three-dimensional supra­molecular network.

1. Chemical context

Over the past few decades, lanthanide-based coordination polymers (LnCPs) have attracted significant attention because their high photoluminescence efficiency and long luminescence lifetime in lighting and full-colour displays (Parker, 2000[Parker, D. (2000). Coord. Chem. Rev. 205, 109-130.]; Bünzli & Piguet, 2005[Bünzli, J. G. & Piguet, C. (2005). Chem. Soc. Rev. 34, 1048-1077.]; Cui et al., 2018[Cui, Y., Zhang, J., He, H. & Qian, G. (2018). Chem. Soc. Rev. 47, 5740-5785.]). Besides transition metal ions, lanthanide ions feature high coordination numbers and flexible coordination geometries, which facilitate the formation of diverse extended structures. Since lanthanide(III) ions have a high affinity to hard donor atoms, ligands containing oxygen atoms such as carb­oxy­lic acids (Xu et al., 2016[Xu, H., Cao, C.-S., Kang, X.-M. & Zhao, B. (2016). Dalton Trans. 45, 18003-18017.]), phospho­ric acids (Mao, 2007[Mao, J.-G. (2007). Coord. Chem. Rev. 251, 1493-1520.]), calixarenes (Ovsyannikov et al., 2017[Ovsyannikov, A., Solovieva, S., Antipin, I. & Ferlay, S. (2017). Chem. Soc. Rev. 352, 151-186.]) and β-diketones (Vigato et al., 2009[Vigato, P. A., Peruzzo, V. & Tamburini, S. (2009). Coord. Chem. Rev. 253, 1099-1201.]) have been used extensively in the synthesis of new types of LnCPs. On the basis of the above considerations, we selected 2,5-dihy­droxy-1,4-benzo­quinone (H2dhbq) as the ligand to react with erbium(III) nitrate hexa­hydrate under solvothermal conditions to construct a new erbium(III)-based CP, [Er2(dhbq)3(H2O)6]·18H2O, (I)[link], which is isotypic with its La, Gd, Yb and Lu analogues (Abrahams et al., 2002[Abrahams, B. F., Coleiro, J., Ha, K., Hoskins, B. F., Orchard, S. D. & Robson, R. (2002). J. Chem. Soc. Dalton Trans. pp. 1586-1594.]). Herein, we report its structure.

2. Structural commentary

The asymmetric unit of (I)[link] contains one third of an Er3+ ion, half of a dhbq2− ligand, one coordinated water mol­ecule and three water mol­ecules of crystallization. The Er3+ ion is located on a threefold rotation axis, whereas the complete dhbq2− anion is generated by a crystallographic inversion center. As can be seen from Fig. 1[link], the Er3+ ion is nine-coordinated by six oxygen atoms from three different dhbq2− ligands and three other oxygen atoms from three coordinated water mol­ecules. The coordination polyhedron of the central Er3+ ion can best be described as having a distorted tricapped trigonal–prismatic geometry, as depicted in Fig. 2[link], in which the O—Er—O bond angles range from 65.01 (5) to 139.97 (7)°. The Er—O bond lengths in the title complex lie between 2.3577 (15) and 2.4567 (15) Å, mean 2.393 Å. The whole dhbq2− anion is nearly planar: the r.m.s. deviation from the mean plane through all of the non-H atoms is 0.021 Å, with a maximum displacement from this plane of 0.033 (2) Å for atom C2. As can be seen from Fig. 3[link], the dhbq2− ligand acts in a μ2-bis(bidentate) bridging mode, connecting two Er3+ ions to form a honeycomb (6,3) sheet extending in the ab plane, having a Er⋯Er separation of 8.7261 (2) Å.

[Scheme 1]
[Figure 1]
Figure 1
The mol­ecular structure of the title complex, showing selected atom labels. Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes: (i) 1 + y − x, 1 − x, z; (ii) 1 − y, x − y, z.
[Figure 2]
Figure 2
View of the distorted tricapped trigonal–prismatic geometry of the central ErIII ion in the title complex. Symmetry codes: (i) 1 + y − x, 1 − x, z; (ii) 1 − y, x − y, z.
[Figure 3]
Figure 3
View of the honeycomb (6,3) sheet extending normal to the c-axis direction.

3. Supra­molecular features

In the crystal, extensive O—H⋯O hydrogen-bonding inter­actions (Table 1[link]) are observed between the oxygen atoms of the coordinated (O3) and lattice (O4 and O5) water mol­ecules as well as between the water (O5 and O6) mol­ecules of crystallization. Other O—H⋯O hydrogen-bonding inter­actions involve O6 and the dhbq2− oxygen atom, and this inter­action further links neighbouring sheets into a three-dimensional supra­molecular structure (Fig. 4[link]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O3—H3A⋯O6i 0.83 (1) 1.94 (1) 2.769 (3) 174 (3)
O3—H3B⋯O5ii 0.84 (1) 1.94 (1) 2.758 (3) 165 (3)
O4—H4A⋯O2iii 0.84 (1) 1.92 (1) 2.738 (3) 167 (4)
O4—H4B⋯O4iv 0.84 (1) 1.98 (1) 2.803 (3) 164 (4)
O5—H5A⋯O1v 0.85 (1) 2.09 (3) 2.870 (3) 153 (5)
O5—H5B⋯O6vi 0.84 (1) 1.95 (1) 2.794 (3) 174 (5)
O6—H6A⋯O4vii 0.85 (1) 1.88 (1) 2.725 (3) 174 (4)
O6—H6B⋯O5 0.84 (1) 1.91 (1) 2.747 (3) 169 (5)
Symmetry codes: (i) [x-y+{\script{2\over 3}}, x+{\script{1\over 3}}, -z+{\script{4\over 3}}]; (ii) [-x+{\script{2\over 3}}, -y+{\script{1\over 3}}, -z+{\script{4\over 3}}]; (iii) -x+y+1, -x+1, z; (iv) [x-y+{\script{1\over 3}}, x-{\script{1\over 3}}, -z+{\script{2\over 3}}]; (v) -y+1, x-y, z; (vi) y, -x+y, -z+1; (vii) -x+1, -y+1, -z+1.
[Figure 4]
Figure 4
View of the packing in the unit cell of the title complex along the c axis. Hydrogen-bonding inter­actions are shown as dashed lines.

4. Database survey

A search of the Cambridge Structural Database (Version 5.39 update February 2018; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) for complexes of dhbq2− ligand gave 94 hits. They include the isotypic crystal structures (Abrahams et al., 2002[Abrahams, B. F., Coleiro, J., Ha, K., Hoskins, B. F., Orchard, S. D. & Robson, R. (2002). J. Chem. Soc. Dalton Trans. pp. 1586-1594.]) with La (MIZXAU), Gd (MIZXEY), Yb (MIZXIC) and Lu (MIZXOI). In most cases, the dhbq2− ligand acts in a μ2-bis­(bidentate) bridging mode to the central metal ions. Comparing the mean Ln—O bond length and the unit-cell volume for the title complex with the La, Gd, Yb and Lu analogues (Abrahams et al., 2002[Abrahams, B. F., Coleiro, J., Ha, K., Hoskins, B. F., Orchard, S. D. & Robson, R. (2002). J. Chem. Soc. Dalton Trans. pp. 1586-1594.]), the values decrease as the ionic radius of the Ln3+ ions decreases in the order La [La—O = 2.540 Å, V = 3289.3 (16) Å3] > Gd [Gd—O = 2.438 Å, V = 3162.7 (7) Å3] > Er [Er—O = 2.393 Å, V = 3107.18 (13) Å3] > Yb [Yb—O = 2.377 Å, V = 3087.1 (4) Å3] > Lu [Lu—O = 2.368 Å, V = 3074.2 (4) Å3], which is consistent with the lanthanide contraction effect.

5. Synthesis and crystallization

A mixture of Er(NO3)3·6H2O (46.2 mg, 0.1 mmol) and H2dhbq (14.2 mg, 0.1 mmol) in distilled H2O (4 ml) and DMF (1 ml) was placed in a 20 ml vial and stirred at room temperature for 10 min. The mixture was sealed tightly, placed in an oven and then heated to 358 K under autogenous pressure for 12 h. After the reactor was cooled to room temperature, block-shaped dark-red crystals were filtered off, washed with deionized H2O and dried in air at room temperature. Yield: 57% based on ErIII source.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. The carbon-bound H atoms were placed in geometrically calculated positions and refined as riding with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C). The hydrogen atoms of the water mol­ecules were located from difference-Fourier maps but were refined with distance restraints of O—H = 0.84 Å and Uiso(H) = 1.5Ueq(O).

Table 2
Experimental details

Crystal data
Chemical formula [Er2(C6H2O4)3(H2O)6]·18H2O
Mr 1181.13
Crystal system, space group Trigonal, R[\overline{3}]
Temperature (K) 296
a, c (Å) 14.0947 (3), 18.0603 (5)
V3) 3107.18 (13)
Z 3
Radiation type Mo Kα
μ (mm−1) 4.13
Crystal size (mm) 0.28 × 0.22 × 0.2
 
Data collection
Diffractometer Bruker D8 QUEST CMOS
Absorption correction Multi-scan (SADABS; Bruker, 2016[Bruker (2016). APEX3, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.677, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 32360, 2522, 2108
Rint 0.065
(sin θ/λ)max−1) 0.758
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.023, 0.042, 1.08
No. of reflections 2522
No. of parameters 118
No. of restraints 8
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 1.67, −1.39
Computer programs: APEX3 and SAINT (Bruker, 2016[Bruker (2016). APEX3, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]) and OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]).

Supporting information


Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Poly[[hexaaquatris(µ-3,6-dioxocyclohexa-1,4-diene-1,4-diolato)dierbium(III)] octadecahydrate] top
Crystal data top
[Er2(C6H2O4)3(H2O)6]·18H2ODx = 1.894 Mg m3
Mr = 1181.13Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3Cell parameters from 8655 reflections
a = 14.0947 (3) Åθ = 2.8–31.7°
c = 18.0603 (5) ŵ = 4.13 mm1
V = 3107.18 (13) Å3T = 296 K
Z = 3Hexagonal prism, dark red
F(000) = 17580.28 × 0.22 × 0.2 mm
Data collection top
Bruker D8 QUEST CMOS
diffractometer
2522 independent reflections
Radiation source: microfocus sealed x-ray tube, Incoatec Iµus2108 reflections with I > 2σ(I)
GraphiteDouble Bounce Multilayer Mirror monochromatorRint = 0.065
Detector resolution: 10.5 pixels mm-1θmax = 32.6°, θmin = 2.8°
φ and ω scansh = 2121
Absorption correction: multi-scan
(SADABS; Bruker, 2016)
k = 1921
Tmin = 0.677, Tmax = 0.746l = 2727
32360 measured reflections
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)] = 0.023H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.042 w = 1/[σ2(Fo2) + (0.0042P)2 + 10.2637P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max = 0.001
2522 reflectionsΔρmax = 1.67 e Å3
118 parametersΔρmin = 1.39 e Å3
8 restraintsExtinction correction: SHELXL (Sheldrick, 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: dualExtinction coefficient: 0.00020 (2)
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
Er10.66670.33330.587213 (10)0.01773 (5)
O10.65928 (12)0.50374 (13)0.58327 (9)0.0236 (3)
O20.54678 (13)0.33698 (13)0.49769 (9)0.0247 (3)
O30.54011 (16)0.33067 (15)0.67424 (11)0.0355 (4)
H3A0.557 (3)0.3878 (16)0.6975 (16)0.055 (10)*
H3B0.4856 (17)0.2781 (17)0.6941 (15)0.046 (9)*
O40.7266 (2)0.52214 (19)0.37540 (12)0.0455 (5)
H4A0.736 (3)0.494 (3)0.4136 (13)0.075 (13)*
H4B0.6643 (16)0.489 (3)0.356 (2)0.079 (14)*
O50.29245 (18)0.15371 (19)0.57009 (14)0.0452 (5)
H5A0.354 (2)0.167 (5)0.587 (3)0.15 (2)*
H5B0.285 (4)0.138 (4)0.5247 (8)0.103 (17)*
O60.18028 (19)0.2663 (2)0.57759 (14)0.0470 (5)
H6A0.213 (3)0.3315 (15)0.594 (2)0.091 (16)*
H6B0.222 (3)0.240 (4)0.576 (2)0.104 (18)*
C10.58618 (18)0.50816 (18)0.54547 (12)0.0212 (4)
C20.51755 (18)0.40906 (18)0.49646 (12)0.0216 (4)
C30.43354 (19)0.40401 (19)0.45415 (13)0.0256 (5)
H30.39020.34240.42550.031*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Er10.01570 (6)0.01570 (6)0.02179 (9)0.00785 (3)0.0000.000
O10.0218 (8)0.0214 (8)0.0293 (8)0.0121 (7)0.0056 (6)0.0019 (6)
O20.0270 (8)0.0222 (8)0.0309 (8)0.0168 (7)0.0069 (7)0.0050 (6)
O30.0371 (11)0.0239 (9)0.0394 (11)0.0106 (8)0.0163 (8)0.0025 (8)
O40.0474 (13)0.0517 (13)0.0376 (12)0.0249 (11)0.0043 (10)0.0091 (10)
O50.0335 (11)0.0505 (13)0.0505 (14)0.0202 (10)0.0094 (10)0.0035 (11)
O60.0434 (13)0.0436 (14)0.0534 (14)0.0212 (11)0.0057 (10)0.0082 (11)
C10.0202 (10)0.0208 (10)0.0221 (10)0.0099 (9)0.0003 (8)0.0004 (8)
C20.0215 (10)0.0217 (10)0.0226 (10)0.0115 (9)0.0011 (8)0.0015 (8)
C30.0259 (11)0.0216 (11)0.0318 (12)0.0137 (10)0.0077 (9)0.0069 (9)
Geometric parameters (Å, º) top
Er1—O1i2.4567 (15)O3—H3B0.836 (10)
Er1—O12.4567 (15)O4—H4A0.838 (10)
Er1—O1ii2.4567 (15)O4—H4B0.842 (10)
Er1—O2ii2.3578 (15)O5—H5A0.845 (10)
Er1—O2i2.3577 (15)O5—H5B0.844 (10)
Er1—O22.3578 (15)O6—H6A0.848 (10)
Er1—O32.3636 (18)O6—H6B0.843 (10)
Er1—O3i2.3636 (18)C1—C21.523 (3)
Er1—O3ii2.3637 (18)C1—C3iii1.398 (3)
O1—C11.263 (3)C2—C31.381 (3)
O2—C21.273 (3)C3—C1iii1.398 (3)
O3—H3A0.831 (10)C3—H30.9300
O1i—Er1—O1119.917 (4)O3—Er1—O1ii139.97 (6)
O1ii—Er1—O1i119.917 (4)O3—Er1—O168.54 (6)
O1ii—Er1—O1119.916 (4)O3ii—Er1—O1ii68.54 (6)
O2i—Er1—O1i65.01 (5)O3i—Er1—O1ii70.00 (6)
O2ii—Er1—O169.91 (5)O3i—Er1—O1i68.54 (6)
O2ii—Er1—O1ii65.01 (5)O3—Er1—O1i70.00 (6)
O2—Er1—O165.01 (5)O3i—Er1—O3ii80.60 (8)
O2—Er1—O1ii134.93 (5)O3i—Er1—O380.60 (8)
O2i—Er1—O1ii69.91 (5)O3—Er1—O3ii80.60 (8)
O2ii—Er1—O1i134.93 (5)C1—O1—Er1119.88 (14)
O2—Er1—O1i69.91 (5)C2—O2—Er1123.42 (14)
O2i—Er1—O1134.93 (5)Er1—O3—H3A118 (2)
O2i—Er1—O2ii78.15 (6)Er1—O3—H3B131 (2)
O2i—Er1—O278.15 (6)H3A—O3—H3B109 (3)
O2ii—Er1—O278.15 (6)H4A—O4—H4B117 (4)
O2ii—Er1—O3ii85.01 (7)H5A—O5—H5B112 (5)
O2—Er1—O3ii134.96 (6)H6A—O6—H6B112 (4)
O2i—Er1—O3ii138.45 (6)O1—C1—C2115.38 (19)
O2i—Er1—O3134.96 (6)O1—C1—C3iii124.7 (2)
O2—Er1—O385.01 (7)C3iii—C1—C2119.92 (19)
O2ii—Er1—O3138.45 (6)O2—C2—C1114.28 (19)
O2i—Er1—O3i85.01 (7)O2—C2—C3125.4 (2)
O2ii—Er1—O3i134.96 (6)C3—C2—C1120.26 (19)
O2—Er1—O3i138.46 (6)C1iii—C3—H3120.1
O3ii—Er1—O1i139.97 (7)C2—C3—C1iii119.8 (2)
O3i—Er1—O1139.97 (6)C2—C3—H3120.1
O3ii—Er1—O170.00 (6)
Er1—O1—C1—C28.1 (2)O2ii—Er1—O1—C196.59 (16)
Er1—O1—C1—C3iii172.37 (18)O2ii—Er1—O2—C286.3 (2)
Er1—O2—C2—C113.9 (3)O2i—Er1—O2—C2166.47 (17)
Er1—O2—C2—C3167.71 (18)O2—C2—C3—C1iii176.2 (2)
O1ii—Er1—O1—C1139.76 (13)O3ii—Er1—O1—C1171.43 (17)
O1i—Er1—O1—C134.5 (2)O3i—Er1—O1—C1126.15 (16)
O1ii—Er1—O2—C2121.30 (16)O3—Er1—O1—C183.94 (16)
O1—Er1—O2—C213.10 (16)O3ii—Er1—O2—C215.9 (2)
O1i—Er1—O2—C2126.04 (18)O3—Er1—O2—C255.53 (17)
O1—C1—C2—O23.1 (3)O3i—Er1—O2—C2125.30 (17)
O1—C1—C2—C3178.4 (2)C1—C2—C3—C1iii2.1 (4)
O2i—Er1—O1—C148.94 (18)C3iii—C1—C2—O2176.4 (2)
O2—Er1—O1—C110.65 (15)C3iii—C1—C2—C32.1 (4)
Symmetry codes: (i) y+1, xy, z; (ii) x+y+1, x+1, z; (iii) x+1, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3A···O6iv0.83 (1)1.94 (1)2.769 (3)174 (3)
O3—H3B···O5v0.84 (1)1.94 (1)2.758 (3)165 (3)
O4—H4A···O2ii0.84 (1)1.92 (1)2.738 (3)167 (4)
O4—H4B···O4vi0.84 (1)1.98 (1)2.803 (3)164 (4)
O5—H5A···O1i0.85 (1)2.09 (3)2.870 (3)153 (5)
O5—H5B···O6vii0.84 (1)1.95 (1)2.794 (3)174 (5)
O6—H6A···O4iii0.85 (1)1.88 (1)2.725 (3)174 (4)
O6—H6B···O50.84 (1)1.91 (1)2.747 (3)169 (5)
Symmetry codes: (i) y+1, xy, z; (ii) x+y+1, x+1, z; (iii) x+1, y+1, z+1; (iv) xy+2/3, x+1/3, z+4/3; (v) x+2/3, y+1/3, z+4/3; (vi) xy+1/3, x1/3, z+2/3; (vii) y, x+y, z+1.
 

Acknowledgements

The authors thank the Faculty of Science and Technology, Thammasat University, for funds to purchase the X-ray diffractometer.

Funding information

Funding for this research was provided by: Thailand Research Fund (grant No. RSA5780056). NP acknowledges the NSTDA STEM Workforce (SCA-CO-2560–3565-TH).

References

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