Redetermination of di­aqua­tris­(4-oxo­pent-2-en-2-olato-κ2 O,O′)lanthanum(III)

Toru Okawara; Kohei Ishihama; Kenji Takehara

doi:10.1107/S1600536814013336

. 2014 Jun 14;70(Pt 7):m258–m259. doi: 10.1107/S1600536814013336

Redetermination of diaquatris(4-oxopent-2-en-2-olato-κ² O,O′)lanthanum(III)

Toru Okawara ^a,^*, Kohei Ishihama ^a, Kenji Takehara ^a

PMCID: PMC4120584 PMID: 25161523

Abstract

The structure of the title compound, [La(C₅H₇O₂)₃(H₂O)₂], has been redetermined to modern standards with anisotropic displacement parameters for all non-H atoms and the hydrogen-bonding pattern unambiguously established [for the previous study, see Phillips et al. (1968 ▶). Inorg. Chem. 7, 2295–2299]. The La³⁺ ion is coordinated by three O,O′-bidentate acetylacetate (acac⁻) ligands and two water molecules, resulting in a fairly regular square-antiprismatic LaO₈ coordination geometry, with both aqua ligands part of the same square face. In the crystal, the neutral complex molecules are linked into [110] chains by O—H⋯O hydrogen bonds.

Related literature

For the previous report on the title compound, see: Phillips et al. (1968 ▶). For related tris(acetylacetonato)lanthanide complexes, see: Watkins et al. (1969 ▶); Kooijman et al. (2000 ▶). For other lanthanide complexes, see: Richardson et al. (1968 ▶); Lama et al. (2007 ▶). graphic file with name e-70-0m258-scheme1.jpg

Experimental

Crystal data

[La(C₅H₇O₂)₃(H₂O)₂]
M _r = 472.26
Triclinic,
a = 8.9245 (12) Å
b = 10.6597 (15) Å
c = 11.3727 (15) Å
α = 96.614 (2)°
β = 100.601 (2)°
γ = 114.325 (2)°
V = 946.8 (2) Å³
Z = 2
Mo Kα radiation
μ = 2.29 mm⁻¹
T = 100 K
0.50 × 0.50 × 0.22 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.40, T _max = 0.63
13810 measured reflections
5213 independent reflections
5068 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.022
wR(F ²) = 0.058
S = 1.06
5213 reflections
240 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.04 e Å⁻³
Δρ_min = −1.41 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: ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536814013336/hb7216sup1.cif

e-70-0m258-sup1.cif^{(18.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814013336/hb7216Isup2.hkl

e-70-0m258-Isup2.hkl^{(255.3KB, hkl)}

Click here for additional data file.^{(3.6KB, cdx)}

Supporting information file. DOI: 10.1107/S1600536814013336/hb7216Isup3.cdx

CCDC reference: 1007160

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

Table 1. Selected bond lengths (Å).

La1—O2	2.4365 (14)
La1—O4	2.4754 (13)
La1—O5	2.4917 (14)
La1—O1	2.5013 (14)
La1—O6	2.5067 (13)
La1—O3	2.5241 (13)
La1—O7	2.5381 (13)
La1—O8	2.5811 (14)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O7—H2W⋯O1ⁱ	0.76 (3)	2.05 (3)	2.7514 (19)	153 (3)
O7—H1W⋯O3ⁱ	0.90 (3)	1.94 (3)	2.7912 (19)	158 (3)
O8—H4W⋯O4ⁱⁱ	0.75 (3)	2.09 (3)	2.7907 (19)	155 (3)
O8—H3W⋯O6ⁱⁱ	0.81 (4)	1.96 (4)	2.721 (2)	155 (3)

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

Acknowledgments

This work was supported by Nanotechnology Platform Project (Kyushu University Molecule and Material Synthesis Platform) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.

supplementary crystallographic information

S1. Comment

Lanthanum (La) is the first element of the lanthanide in the periodic table. Although La does not show any luminescent properties, it has worth investigating as referece complexs of other luminescent lanthanide analogs. Because structural features of La^III complexes are similar to those of other lanthanide cases, they can be structurally characterized by nuclear magnetic resonance spectroscopy. La^III acetylacetonate complexes are used as a precursor of further functionalized complexes. Herein we redetermined the molecular structure of La(acac)₃(H₂O)₂ (compound I) which has been firstly reported by Phillips et al. (1968). In the previous study, all of the oxygen and carbon atoms have been refined isotropically. We have successfully obtained the reliable anisotropic displacement parameters for all non-hydrogen atoms. The molecular geometry of the compound I was almost identical to previous report. The La^III is ligated from three acetylacetonate ligands and two aqua ligands which are forming 8-coordinate structure around La^III (Figure 1). The average distance of oxygen atoms of acetylacetonate (O1—O6) and La^III is 2.489 (30) Å while the original structure showed the average distance of 2.473 (24) Å. The two aqua ligands also align at parpendicular position each other in which O7—La1—O8 angle of 75.20 (5)^o. Similar coordination structures are seen in Ho^III(acac)₃(H₂O)₂ by Kooijman et al. (2000) and Yb^III(acac)₃(H₂O) by Watkins et al. (1969). Both complexes have three acac ligands and the former one has nearly identical structure in which two aqua ligands ligate to the central ion and complete 8-coordinated square antiprismatic structure. The longest bond lengths between the central lanthanide ion and the oxygen atoms of acac ligands were observed for the compound I due to difference in their ionic radii. The compound I in the crystal are connected by four hydrogen bonding, O7—O1ⁱ (symmetry codes: (i) 2 - x, 2 - y, 1 - z), O7—O3ⁱ, O8—O4ⁱⁱ (symmetry codes: (ii) 1 - x, 1 - y, 1 - z) and O8—O6ⁱⁱ, which are forming a one dimensional hydrogen bonding network (Figure 2) propagating in the [110] direction.

S2. Experimental

An water suspension (10 ml) of acetylacetone (161.9 mg, 1.62 mmol) and LaCl₃^.7H₂ O (200.0 mg, 0.54 mmol) were stirred under room temperature. Quantitative amount of NaOH (64.7 mg, 1.62 mmol) was added to the suspension. A white precipitate was immediately generated. The precipitate was filtered and recrystallized from CH₂Cl₂ and methanol in the presence of small amount of water (ca. 3%). Colorless blocks of the title compound were obtained in a few days and mounted on a glass capillary. Yield: 77.9 mg, (31%). Analysis: calculated for C₁₅H₂₅LaO₈ ([La(acac)₃(H₂O)₂]): C 38.15, H 5.34%; found: C 37.80, H 5.16%. ESI-TOF-MS (CH₃OH): m/z 336.97 (calcd: 337.00 for [M–acac–2H₂O]⁺).