Bis[2,6-bis­(1H-pyrazol-1-yl)pyridine]­deca­kis­(μ2-3-nitro­benzoato)bis­(3-nitro­benzoato)tetra­dysprosium(III): a linear tetra­nuclear dysprosium compound based on mixed N- and O-donor ligands

Rong Hua; Xiao-Liu Wu; Jin-Ying Li

doi:10.1107/S1600536814006060

. 2014 Apr 2;70(Pt 5):m162–m163. doi: 10.1107/S1600536814006060

Bis[2,6-bis(1H-pyrazol-1-yl)pyridine]decakis(μ₂-3-nitrobenzoato)bis(3-nitrobenzoato)tetradysprosium(III): a linear tetranuclear dysprosium compound based on mixed N- and O-donor ligands

Rong Hua ^a, Xiao-Liu Wu ^a, Jin-Ying Li ^a,^*

PMCID: PMC4011298 PMID: 24860300

Abstract

The title compound, [Dy₄(C₇H₄NO₄)₁₂(C₁₁H₉N₅)₂] or Dy₄(L1)₁₂(L2)₂, where HL1 = 3-nitrobenzoic acid and HL2 = 2,6-bis(1H-pyrazol-1-y1)pyridine, is a linear tetranuclear complex possessing inversion symmetry. The two central inversion-related Dy^III atoms are seven-coordinate, DyO₇, with a monocapped triangular-prismatic geometry. The outer two Dy^III atoms are eight-coordinate, DyO₅N₃, with a bicapped triangular-prismatic geometry. The outer adjacent Dy^III atoms are bridged by three L1⁻ carboxylate groups, while the inner inversion-related Dy^III atoms are bridged by four L1⁻ carboxylate groups. The L2 ligands are terminally coordinated to the outer Dy^III atoms in a tridentate manner. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (001). Two carboxylate O atoms, and N and O atoms of three nitro groups, are disordered over two positions, with a refined occupancy ratio of 0.552 (6):0.448 (6).

Related literature

For background to single molecular magnets, see: Zheng et al. (2008 ▶); Wu et al. (2009 ▶); Guo et al. (2012 ▶). For examples of multinuclear Dy-based compounds, see: Abbas et al. (2010 ▶); Blagg et al. (2011 ▶); Hussain et al. (2009 ▶); Tian et al. (2012 ▶); Xu et al. (2010 ▶). For details of a linear tetranuclear Dy^III complex, see: Lin et al. (2012 ▶). graphic file with name e-70-0m162-scheme1.jpg

Experimental

Crystal data

[Dy₄(C₇H₄NO₄)₁₂(C₁₁H₉N₅)₂]
M _r = 3065.81
Triclinic,
a = 14.2514 (3) Å
b = 14.9274 (5) Å
c = 14.9616 (3) Å
α = 100.443 (2)°
β = 111.754 (1)°
γ = 99.695 (2)°
V = 2808.87 (12) Å³
Z = 1
Mo Kα radiation
μ = 2.74 mm⁻¹
T = 296 K
0.20 × 0.20 × 0.19 mm

Data collection

Bruker APEX2 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.611, T _max = 0.624
42971 measured reflections
11020 independent reflections
9747 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.022
wR(F ²) = 0.058
S = 1.13
11020 reflections
848 parameters
24 restraints
H-atom parameters constrained
Δρ_max = 0.66 e Å⁻³
Δρ_min = −0.67 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2005 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536814006060/su2704sup1.cif

e-70-0m162-sup1.cif^{(65.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814006060/su2704Isup2.hkl

e-70-0m162-Isup2.hkl^{(538.8KB, hkl)}

CCDC reference: 992494

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10⋯O22ⁱ	0.93	2.45	3.366 (4)	170
C43—H43⋯O2ⁱⁱ	0.93	2.47	3.212 (5)	137
C51—H51⋯O6ⁱⁱⁱ	0.93	2.32	3.243 (5)	172

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

Acknowledgments

This work was supported by the Foundation of Jiangxi Educational Committee (No. GJJ13472).

supplementary crystallographic information

1. Comment

Single molecule magnets (SMMs) have potential applications in data storage, quantum information processing (Zheng et al., 2008), magnetic refrigeration, and high-density information storage (Wu et al., 2009).SMMs are mononuclear or multinuclear transition metal-based clusters or rare-earth metal-based clusters with no interactions between molecules. Mn^II-based SMMs were the first to be fully investigated, whereas recently 4f- or 5f-based compounds, especially Dy^III-based compounds, have been investigated because of their potential significant magnetic anisotropy and large energy barriers (Guo et al., 2012). A number of multinuclear Dy-based compounds have been synthesized, for example, Dy₂ (Xu et al., 2010), Dy₃ (Hussain et al., 2009), Dy₄ (Abbas et al., 2010), Dy₅ (Blagg et al., 2011), and Dy₈ (Tian et al., 2012). In line with our interest in designing multinuclear Dy-based compounds, we report herein on the synthesis and crystal structure of a new and novel linear tetranuclear dysprosium compound, which is based on mixed N-donor and O-donor ligands.

The molecular structure of the title compound is illustrated in Fig. 1. It possesses inversion symmetry and the asymmetric unit is composed of two crystallographic independent Dy^III ions, six crystallographic independent 3-nitro benzoate L1^- ligands, and one crystallographic independent 2,6-di(1H-pyrazol-1-y1)pyridine L2 ligand. The coordination spheres of the two Dy^III ion are different. Atom Dy1 has a DyO₅N₃ bi-capped triangular-prism geometry, completed by three nitrogen atoms (N1, N3, N5) from one L2 ligand, and five oxygen atoms (O1, O2, O5, O9, O13) from three L1^- ligands, where the capped atoms are N5, O9. Atom Dy2 has a DyO₇ monocapped triangular-prism geometry, created by seven oxygen atoms (O6, O10, O14, O17, O18, O21, O22) from seven L1^- ligands, where the capped atom is O10. The Dy—O/N bond length are in the normal range. The L2 ligand coordinates to the Dy1 atoms in a tridentate manner, whereas the L1^- ligands display two kinds of coordination mode, chelate and bidentate. The chelate mode involves the outer pair of Dy atoms, while the bidentate mode involves the inversion related Dy2 atoms in the center of the tetranuclear complex.

The overall structure of the title compound is a tetranuclear cluster in the Dy1—Dy2—Dy2A—Dy1A arrangement, see Figs. 1, 2, and 3. Atoms Dy1 and Dy2 are bridged by three L1^- carboxylate ligands with a metal-to-metal distance of 4.88 (2) Å. Through inversion symmetry the Dy1—Dy2 fragment connects to the symmetry-related Dy2A···Dy1A fragment via the Dy2—Dy2A connection linked by four L1^- carboxyl groups. The Dy2···Dy2A distance is 4.34 (2) Å. The span of this tetranuclear cluster estimated by the distance of two terminal metal ions Dy1 and Dy1A is 14.07 (2) Å [symmetry code: A = -x, -y+1, -z].

In the crystal, molecules are linked via C-H···O hydrogen bonds forming a two-dimensional network parallel to (001); see Table 1 and Fig. 4.

Although the ligand 2,6-di(1H-pyrazol-1-y1) pyridine is extensively used to construct metal-organic compounds, it has rarely been used in combination with lanthanide ions, and there is no precedent of a cluster compound containing a lanthanide ion and the ligand 2,6-di(1H-pyrazol-1-y1)pyridine. The title compound is the first such compound to be synthesized and is a promising way to target multinuclear lanthanide clusters.

Moreover, in the literature, there is only one other report of a linear tetranuclear Dy^III complex (Lin et al., 2012), [Dy₄(L)₂(C₆H₅COO)₁₂(MeOH)₄] (L = 2,6-bis((furan-2-ylmethylimino)methyl)-4-methyl-phenol), where the Dy^III sites are fully coordinated by O atoms, rather than being coordinated by both O and N atoms as observed in the title compound. Interestingly the metal-to-metal distances (4.24 (2) Å and 4.06 (2) Å) reported there are slightly shorter than those observed in the title compound.

2. Experimental

DyCl₃ (0.2 mmol), 2,6-di(1H-pyrazol-1-y1)pyridine (2 mmol), nitro benzoic acid (0.8 mmol), Na₂CO₃ (0.4 mmol) and H₂O (10 mL) were mixed together, then transferred into a 25 ml Teflon-lined reactor. This was heated at 483 K for 3 days. The mixture was then cooled to room temperature, at a rate of 3 K/h, and yielded block-like colourles crystals in a 58% yield based on Dy.