{μ-6,6′-Dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato}-μ-nitrato-dinitratoholmium(III)zinc(II)

Yi-An Xiao; Yan Sui; Xiu-Guang Yi; Jian-Hong Wu; Li-Ping Zhang

doi:10.1107/S1600536808013743

This article has been retracted.

Retraction in: Acta Crystallogr Sect E Struct Rep Online. 2010 Mar 17;66(Pt 4):e21 See also: PMC Retraction Policy

. 2008 May 14;64(Pt 6):m804–m805. doi: 10.1107/S1600536808013743

{μ-6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}-μ-nitrato-dinitratoholmium(III)zinc(II)

Yi-An Xiao ^a, Yan Sui ^b,^*, Xiu-Guang Yi ^b, Jian-Hong Wu ^b, Li-Ping Zhang ^b

PMCID: PMC2961445 PMID: 21202491

Abstract

In the title heteronuclear Zn^II–Ho^III complex (systematic name: {μ-6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato-1κ⁴ O ¹,O ^1′,O ⁶,O ^6′:2κ⁴ O ¹,N,N′,O ^1′)-μ-nitrato-1:2κ² O:O′-dinitrato-1κ⁴ O,O′-holmium(III)zinc(II)), [HoZn(C₁₈H₁₈N₂O₄)(NO₃)₃], with the hexadentate Schiff base compartmental ligand N,N′-bis(3-methoxysalicylidene)ethylenediamine (H₂ L), the Ho and Zn atoms are triply bridged by two phenolate O atoms of the Schiff base ligand and one nitrate ion. The five-coordinate Zn atom is in a square-pyramidal geometry with the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The Ho^III center has a ninefold coordination environment of O atoms, involving the phenolate O atoms, two methoxy O atoms, two O atoms from two nitrate ions and one from the bridging nitrate ion. Weak intermolecular C—H⋯O interactions generate a two-dimensional double-layer structure.

Related literature

For related literature, see: Baggio et al. (2000 ▶); Caravan et al. (1999 ▶); Edder et al. (2000 ▶); Knoer et al. (2005 ▶); Sui et al. (2006 ▶, 2007 ▶).

Experimental

Crystal data

[HoZn(C₁₈H₁₈N₂O₄)(NO₃)₃]
M _r = 742.67
Monoclinic,
a = 10.694 (4) Å
b = 16.481 (7) Å
c = 14.921 (6) Å
β = 99.667 (6)°
V = 2592.4 (18) Å³
Z = 4
Mo Kα radiation
μ = 4.03 mm⁻¹
T = 293 (2) K
0.16 × 0.16 × 0.10 mm

Data collection

Bruker APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.565, T _max = 0.689
15217 measured reflections
4499 independent reflections
3377 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.093
S = 1.02
4499 reflections
345 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.60 e Å⁻³
Δρ_min = −1.18 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2; data reduction: APEX2; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: APEX2; software used to prepare material for publication: APEX2 and publCIF (Westrip, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808013743/at2567sup1.cif

e-64-0m804-sup1.cif^{(22.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808013743/at2567Isup2.hkl

e-64-0m804-Isup2.hkl^{(220.4KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Ho1—O1	2.293 (3)
Ho1—O2	2.298 (3)
Ho1—O3	2.604 (4)
Ho1—O4	2.604 (4)
Ho1—O6	2.323 (4)
Ho1—O8	2.448 (4)
Ho1—O9	2.481 (4)
Ho1—O11	2.430 (4)
Ho1—O12	2.468 (4)
Zn1—O1	2.005 (4)
Zn1—O2	2.022 (3)
Zn1—O5	1.979 (4)
Zn1—N1	2.047 (4)
Zn1—N2	2.021 (5)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O11ⁱ	0.93	2.45	3.377 (7)	174
C10—H10A⋯O13ⁱⁱ	0.97	2.54	3.483 (8)	165

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

Acknowledgments

We gratefully acknowledge financial support from the Department of Education, JiangXi Province (No. 2007317) and the Natural Science Foundation of JiangXi Province (No. 2007GZH1667).

supplementary crystallographic information

Comment

The potential applications of trivalent lanthanide complexes as contrast agent for magnetic resonance imaging and stains for fluorescence imaging have prompted considerable interest in the preparation, magnetic and optical properties of 3d-4f hetorometallic dinuclear complexes (Baggio et al., 2000; Caravan et al., 1999; Edder et al., 2000; Knoer et al., 2005). As part of our investigations into the structure and applications of 3d-4f hetorometallic Schiff base complexes (Sui et al. 2006; Sui et al. 2007), we report here the synthesis and X-ray crystal structure analysis of the title complex, (I), a new Zn^II—Ho^III complex with salen-type Schiff base N,N'-bis(3-methoxysalicylidene) ethylenediamine (H₂L).

Complex (I) crystallizes in the space group P2₁/n, with zinc and holmium triply bridged by two phenolate O atoms provided by the Schiff base ligand and one nitrate ion. The inner salen-type cavity is occupied by zinc(II), while holmium(III) is present in the open and larger portion of the dinucleating compartmental Schiff base ligand.

The Ho^III center has a ninefold coordination environment of O atoms, involving the phenolate O atoms, two methoxy O atoms, two O atoms from two nitrate ions and one from the bridging nitrate ion. The four kinds of Ho—O bond distances are significantly different, the longest being the Ho—O (methoxy) separations and the shortest being the Ho—O (phenolate).

The Zn^II is in a square-pyramidal geometry and is five-coordinated by two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The Zn atom is 0.6067 (4) Å below the mean N₂O₂ plane with an average deviation from the plane of 0.0380 (3) Å, which construct the bottom of square-pyramid. The Zn—O5 (bridging nitrate) separation is 1.979 (4) Å and the angles of this Zn—O vector with the Zn—N or Zn—O bonds lie between 102.5 (4)° and 112.6 (4)°, which suggesting that the Zn^II is in a slightly distorted square-pyramidal conformation.

Adjacent molecules are held together by weak interactions [C5(H5)···O11ⁱ= 3.377 (7) Å and C10(H10A)···O13ⁱⁱ= 3.483 (8) Å; symmetry codes: (i) -1/2 + x, 1/2 - y, 1/2 + z; (ii) 1 - x, -y, 2 - z]. These link the molecules into a two-dimensional double layer structure (Fig 2).

Experimental

H₂L was prepared by the 2:1 condensation of 3-methoxysalicylaldehyde and ethylenediamine in methanol. Complex (I) was obtained by the treatment of zinc(II) acetate dihydrate (0.188 g, 1 mmol) with H₂L (0.328 g, 1 mmol) in methanol solution (80 ml) under reflux for 3 h and then for another 3 h after the addition of holmium(III) nitrate hexahydrate (0.459 g, 1 mmol). The reaction mixture was cooled and the resulting precipitate was filtered off, washed with diethyl ether and dried in vacuo. Single crystals of (I) suitable for X-ray analysis were obtained by slow evaporation at room temperature of a methanol solution. Analysis calculated for C₁₈H₁₈HoN₅O₁₃Zn: C 29.11 H 2.44, Ho 22.21, N 9.43, Zn 8.80%; found: C 29.20, H 2.45, Ho 22.30, N 9.50, Zn 8.90%. IR (KBr, cm^-1): 1640 (C=N), 1386,1490 (nitrate).