Diaqua­tris­(nitrato-κ2 O,O′){2,2′-[pyridine-2,6-diylbis(methyl­ene­oxy)]dibenzaldehyde-κO 1}dysprosium(III)–2,2′-[pyridine-2,6-diylbis(methyl­ene­oxy)]dibenzaldehyde (1/1)

Sara Luisa Rodríguez de Luna; Perla Elizondo; Sylvain Bernès; Marcos Flores-Alamo; Leyda E López

doi:10.1107/S160053681203680X

. 2012 Sep 5;68(Pt 10):m1239–m1240. doi: 10.1107/S160053681203680X

Diaquatris(nitrato-κ² O,O′){2,2′-[pyridine-2,6-diylbis(methyleneoxy)]dibenzaldehyde-κO ¹}dysprosium(III)–2,2′-[pyridine-2,6-diylbis(methyleneoxy)]dibenzaldehyde (1/1)

Sara Luisa Rodríguez de Luna ^a, Perla Elizondo ^a, Sylvain Bernès ^a,^*, Marcos Flores-Alamo ^b, Leyda E López ^a

PMCID: PMC3470130 PMID: 23125574

Abstract

The title compound, [Dy(NO₃)₃(C₂₁H₁₇NO₄)(H₂O)₂]·C₂₁H₁₇NO₄, may be considered as an organic–metalorganic 1:1 co-crystal, in which the two dialdehyde molecules act as a ligand and as an organic moiety, respectively. The Dy^III atom coordinates nine O atoms from the organic ligand, bidentate nitrate ions and water molecules, approximating a square-face-tricapped trigonal–prismatic geometry. The coordinated dialdehyde is not planar: the uncoordinated oxybenzaldehyde group is twisted by 39.96 (4)° from the rest of the ligand. In contrast, the free organic moiety is almost planar, with an r.m.s. deviation of 0.15 Å. In the crystal, segregated stacks of dialdehyde are formed in the [100] direction. For the complex, the shortest π–π contact is found at 3.781 (2) Å, and for the free ligand, at 3.785 (2) Å. The crystal structure is further stabilized by O—H⋯O and O—H⋯N hydrogen bonds in which coordinated water molecules are the donor groups.

Related literature

For the X-ray structure of the free ligand and other rare-earth complexes based on this ligand, see: Rodríguez De Luna et al. (2010 ▶). For isotypic complexes, see: Garza Rodríguez (2010 ▶). For the nomenclature of 9-coordinated metal centers, see: IUPAC (2005 ▶).

Experimental

Crystal data

[Dy(NO₃)₃(C₂₁H₁₇NO₄)(H₂O)₂]·C₂₁H₁₇NO₄
M _r = 1079.27
Triclinic,
a = 7.7552 (3) Å
b = 16.1249 (8) Å
c = 17.7178 (7) Å
α = 75.531 (4)°
β = 85.173 (3)°
γ = 88.398 (4)°
V = 2137.71 (16) Å³
Z = 2
Mo Kα radiation
μ = 1.84 mm⁻¹
T = 136 K
0.43 × 0.26 × 0.12 mm

Data collection

Agilent Xcalibur Atlas Gemini diffractometer
Absorption correction: analytical [CrysAlis PRO (Agilent, 2010 ▶); based on expressions derived by Clark & Reid (1995 ▶)] T _min = 0.599, T _max = 0.816
15907 measured reflections
8436 independent reflections
7464 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.030
wR(F ²) = 0.066
S = 1.05
8436 reflections
616 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.95 e Å⁻³
Δρ_min = −0.88 e Å⁻³

Data collection: CrysAlis CCD (Agilent, 2010 ▶); cell refinement: CrysAlis CCD (Agilent, 2010 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S160053681203680X/vn2050sup1.cif

e-68-m1239-sup1.cif^{(53.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681203680X/vn2050Isup2.hkl

e-68-m1239-Isup2.hkl^{(412.6KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Dy1—O1	2.435 (2)
Dy1—O5	2.327 (2)
Dy1—O6	2.320 (2)
Dy1—O7	2.410 (2)
Dy1—O8	2.437 (2)
Dy1—O10	2.443 (2)
Dy1—O11	2.429 (2)
Dy1—O13	2.460 (2)
Dy1—O14	2.403 (2)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H51⋯N1ⁱ	0.76 (4)	1.97 (4)	2.724 (3)	173 (4)
O5—H52⋯O12ⁱⁱ	0.73 (3)	2.19 (4)	2.907 (3)	168 (4)
O6—H61⋯O4ⁱⁱⁱ	0.71 (3)	2.10 (3)	2.797 (3)	169 (4)
O6—H62⋯N51ⁱⁱⁱ	0.86 (3)	1.86 (4)	2.712 (3)	177 (3)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors thank the PAICyT program (Programa de Apoyo a la Investigación Científica y Tecnológica), Universidad Autónoma de Nuevo León, for supporting this work (project No. CE 600–10).

supplementary crystallographic information

Comment

Lanthanides (Ln) are well known for giving high and rather unpredictable coordination numbers, in the range 8 to 12. For example, in the case of O-donor ligands, the coordination sphere may be completed by water molecules. Such modifications are reflected in the flexible coordination geometry of these complexes, which, in turn, has consequences on the physical properties characteristics of these metals.

While working on the synthesis of an isotypic series of Ln^III complexes with photoluminescent properties (Rodríguez De Luna et al., 2010), we realised that, occasionally, a by-product crystallized with the desired complex, although elemental analysis systematically matched the expected formula. The desired complex had formula [Ln^IIIL₂(NO₃)₃(H₂O)₂] where L is a monodentate dialdehyde ligand, 2,2'-[pyridine-2,6-diyl-bis(methyleneoxy)]dibenzaldehyde, giving a coordination number of 10 for the metal. This compound crystallizes readily in space group C2/c. The crystallographic analysis revealed that the by-product, which crystallizes in space group P1, is isoformular, although the coordination number is reduced to 9, because one L ligand, present in the asymmetric unit, is not coordinated to the metal. The resulting formula is then [Ln^IIIL(NO₃)₃(H₂O)₂].L, which may be seen as an organic-metalorganic system.

So far, we have detected the presence of this new complex with Ln = Ho^III, Tb^III and Dy^III, on the basis of unit-cell parameters (Garza Rodríguez, 2010). The X-ray characterization is however complicated by the very low yield and the poor quality of single crystals we have obtained. The present report is for Ln = Dy^III, which gave a suitable refinement.

The asymmetric unit contains one complex and one free ligand (Fig. 1). The Dy^III atom is bonded to the monodentate L ligand, three bidentate nitrate ions, and two water molecules, forming nine Dy—O bonds in the range 2.320 (2)–2.460 (2) Å. The resulting coordination geometry approximates a square-face-tricapped trigonal prismatic polyhedron (polyhedral symbol in the IUPAC nomenclature: TPRS-9; IUPAC, 2005), with distortions from the ideal D₃_h symmetry induced by the nitrate bite angles (Fig. 1, inset). The organic ligand is not planar, and the peripheral ring, C15···C21/O3/O4 is twisted by 39.96 (4)° from the rest of the ligand. The free ligand is more planar, and presents a conformation reminiscent of that observed in the crystal structure of pure L (Rodríguez De Luna et al., 2010).

The crystal structure features segregated stacks for organic and metalorganic moieties (Fig. 2). The free organic molecules are stacked in the [100] direction with π···π interactions between pyridine rings in the range 3.785 (2)–4.528 (2) Å. Because of the deviation from planarity of the whole molecule, benzaldehyde rings are less engaged in π···π interactions, with centroid-to-centroid separations in the range 4.139 (3)–5.156 (3) Å. L ligands bonded to the metals also interact in the same direction, and the most favorable π···π separation is found at 3.781 (2) Å.

Experimental

The title compound was obtained by mixing 2,2'-[pyridine-2,6-diyl-bis(methyleneoxy)]dibenzaldehyde (L, 50 mg in 15 ml of acetonitrile) and Dy(NO₃)₃.5H₂O (100 mg in 2 ml of acetonitrile), at room temperature. The mixture was refluxed for 5 h and then cooled to room temperature. After evaporation of the solvent, a few crystals of the complex were collected.