catena-Poly[[lead(II)-bis­(μ2-quinolin-8-ol­ato)-κ3 N,O:O;κ3 O:N,O] N,N-di­methyl­formamide hemisolvate]

Akbar Ghaemi; Zohreh Dadkhah; Seik Weng Ng; Edward R T Tiekink

doi:10.1107/S1600536812002796

. 2012 Jan 31;68(Pt 2):m210. doi: 10.1107/S1600536812002796

catena-Poly[[lead(II)-bis(μ₂-quinolin-8-olato)-κ³ N,O:O;κ³ O:N,O] N,N-dimethylformamide hemisolvate]

Akbar Ghaemi ^a,^‡, Zohreh Dadkhah ^a, Seik Weng Ng ^b, Edward R T Tiekink ^c,^*

PMCID: PMC3274927 PMID: 22346874

Abstract

The asymmetric unit of the title compound, {[Pb(C₉H₆NO)₂]·0.5C₃H₇NO}_n, comprises Pb(quinolate)₂ and half a dimethylformamide molecule (which is disordered about a centre of inversion). The quinolate ligands N,O-chelate to a Pb^II ion and simultaneously bridge a neighbouring Pb^II ion to form a polymeric chain along [100] comprising Pb-linked Pb₂O₂ distorted rhombi. These chains pack to form a square grid, with the channels thus defined occupied by the disordered solvent molecules.

Related literature

For a recent Pb^II mixed quinolate carboxylate structure, see: Ghaemi et al. (2012 ▶). For the structure of the solvent-free Pb^II quinolate, see: Zhu et al. (2005 ▶).

Experimental

Crystal data

[Pb(C₉H₆NO)₂]·0.5C₃H₇NO
M _r = 532.04
Triclinic,
a = 8.1841 (2) Å
b = 9.6606 (3) Å
c = 10.8619 (3) Å
α = 96.683 (3)°
β = 98.277 (2)°
γ = 94.225 (3)°
V = 840.48 (4) Å³
Z = 2
Mo Kα radiation
μ = 10.06 mm⁻¹
T = 100 K
0.30 × 0.08 × 0.04 mm

Data collection

Agilent SuperNova Dual diffractometer with Atlas detector
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010 ▶) T _min = 0.152, T _max = 0.689
13299 measured reflections
3866 independent reflections
3613 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.021
wR(F ²) = 0.049
S = 1.01
3866 reflections
272 parameters
36 restraints
H-atom parameters constrained
Δρ_max = 1.23 e Å⁻³
Δρ_min = −0.71 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812002796/hg5166sup1.cif

e-68-0m210-sup1.cif^{(23.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812002796/hg5166Isup2.hkl

e-68-0m210-Isup2.hkl^{(189.5KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Pb—O2	2.408 (2)
Pb—O1	2.468 (2)
Pb—N2	2.470 (3)
Pb—N1	2.566 (3)
Pb—O1ⁱ	2.618 (2)
Pb—O2ⁱⁱ	2.812 (2)

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

Acknowledgments

The authors gratefully acknowledge practical support of this study by the Islamic Azad University (Saveh Branch), and thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (grant No. UM·C/HIR/MOHE/SC/12).

supplementary crystallographic information

Comment

During the course of recent studies into the structural chemistry of mixed Pb^II quinolate carboxylates (Ghaemi et al., 2012), the title binary Pb^II quinolate was isolated as a DMF hemi-solvate, (I), from an attempted reaction with maleic acid. The crystal structure of the solvent free and polymeric Pb(quinolate)₂ has been described (Zhu et al., 2005).

The asymmetric unit of (I) comprises Pb(quinolate)₂ and half a solvent DMF molecule (this is disordered over a centre of inversion), Fig. 1. Each quinolate anion N,O-chelates a Pb^II atom and at the same time bridges a neighbouring Pb^II atom via the carbonyl-O atom. The result is a polymeric chain comprising alternating Pb₂O₂ rhombi, Fig. 2. The degree in asymmetry in the Pb—O bridges varies, Table 1. The coordination geometry of the Pb^II atom is based on a distorted pentagonal bipyramid with one N atom occupying an axial site. The lone pair of electrons occupies the second axial position. It is noted that the O3 and O3' atoms (each with a 0.25 site occupancy factor) of disordered DMF molecule approach the Pb^II at distances 2.903 (12) and 2.977 (12) Å, respectively. These are not trans to the axial N atom forming angles of approximately 140°. If one of the DMF-O atoms is included as part of the coordination sphere, the coordination geometry would be described as ψ-dodecahedral.

In the crystal packing, the polymeric chains pack into a square grid which defines channels in which reside the disordered solvent molecules, Fig. 3. The aforementioned weak Pb···O(DMF) interactions serve to connect the polymeric chains into a layer in the ab plane.

Experimental

The title complex was obtained by the following method. 8-Hydroxyquinoline (0.036 g, 0.25 mmol) was added to an aqueous solution (5 ml) of Pb(NO₃)₂ (0.082 g, 0.25 mmol). The mixture was stirred for 15 min. Then to this solution, a DMF solution (5 ml) of maleic acid (0.029 g, 0.25 mmol) which with triethylamine neutralized was added slowly at room temperature. This mixture was filtered. After keeping the filtrate in air, crystals were formed at the bottom of the vessel on slow evaporation of the solvents at room temperature. M.p. 590 K. Yield: 65%.