catena-Poly[[bis(pyridine)­lead(II)]bis(μ-penta­fluoro­benzene­thiol­ato)]

Sarah E Appleton; Glen G Briand; Andreas Decken; Anita S Smith

doi:10.1107/S160053681101659X

. 2011 May 7;67(Pt 6):m714. doi: 10.1107/S160053681101659X

catena-Poly[[bis(pyridine)lead(II)]bis(μ-pentafluorobenzenethiolato)]

Sarah E Appleton ^a, Glen G Briand ^a,^*, Andreas Decken ^b, Anita S Smith ^a

PMCID: PMC3120355 PMID: 21754614

Abstract

The title compound, [Pb(C₆F₅S)₂(C₅H₅N)₂]_n, shows the Pb^II atom in a ψ-trigonal bipyramidal S₂N₂ bonding environment. Pyridine N atoms occupy axial sites, while thiolate S atoms and a stereochemically active lone pair occupy equatorial sites. Very long intermolecular Pb⋯S interactions [3.618 (4) and 3.614 (4) Å] yield a weakly associated one-dimensional polymeric structure extending parallel to [010].

Related literature

Lead(II) thiolates tend to form polymeric structures in the solid state via intermolecular Pb⋯S interactions, see: Davidovich et al. (2010 ▶) and references therein; Eichhöfer (2005 ▶). However, the bonding environment at lead and the degree of intermolecular bonding may be altered via the introduction of Lewis base ligands that occupy metal coordination sites, see: Appleton et al. (2004 ▶); Briand et al. (2007 ▶). It has been shown that [(F₅C₆S)₂Pb]_n exhibits a three-dimensional framework structure containing hexacoordinated Pb^II atoms (Fleischer et al., 2006 ▶). For van der Waals radii, see: Bondi (1964 ▶); Brown (1978 ▶).

Experimental

Crystal data

[Pb(C₆F₅S)₂C₅H₅N)₂]
M _r = 763.63
Monoclinic,
a = 19.9288 (19) Å
b = 5.0416 (5) Å
c = 24.9155 (19) Å
β = 111.339 (3)°
V = 2331.7 (4) Å³
Z = 4
Mo Kα radiation
μ = 7.51 mm⁻¹
T = 198 K
0.57 × 0.15 × 0.10 mm

Data collection

Bruker SMART1000/P4 diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a ▶) T _min = 0.099, T _max = 0.521
6756 measured reflections
2575 independent reflections
2421 reflections with I > 2σ(I)
R _int = 0.055

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.097
S = 1.06
2575 reflections
168 parameters
H-atom parameters constrained
Δρ_max = 3.83 e Å⁻³
Δρ_min = −2.71 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b ▶); molecular graphics: SHELXTL (Sheldrick, 2008b ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681101659X/hg5027sup1.cif

e-67-0m714-sup1.cif^{(15.6KB, cif)}

Supplementary material file. DOI: 10.1107/S160053681101659X/hg5027Isup2.cdx

Structure factors: contains datablocks I. DOI: 10.1107/S160053681101659X/hg5027Isup3.hkl

e-67-0m714-Isup3.hkl^{(126.6KB, hkl)}

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

Acknowledgments

This work was supported by the Natural Sciences and Engineering Research Council of Canada and Mount Allison University.

supplementary crystallographic information

Comment

Lead(II) thiolates tend to form polymeric structures in the solid state via intermolecular Pb ··· S interactions (Davidovich et al., 2010, and references therein; Eichhöfer, 2005). However, the bonding environment at lead and the degree of intermolecular bonding may be altered via the introduction of Lewis base ligands that occupy metal coordination sites (Appleton et al., 2004; Briand et al., 2007). It has been shown that [(F₅C₆S)₂Pb]_n exhibits a three-dimensional layered structure containing hexacoordinated Pb^II atoms (Fleischer et al., 2006). The corresponding bis-pyridine adduct (I) (Fig. 1) shows Pb1 in a ψ -trigonal bipyramidal bonding environment, with two pyridine nitrogen atoms in trans axial sites [N1—Pb—N2 = 177.29 (17)°] and two sulfur atoms in cis equatorial sites [S1—Pb—S2 = 87.13 (6)°]. The remaining "open" equatorial site is presumably occupied by the stereochemically active lone pair of Pb^II. This is a similar bonding motif to that observed for (2,6-Me₂C₆H₃S)₂Pb × 2py (Appleton et al., 2004), but shows some subtle structural differences. The Pb—N bond distances in (I) [Pb—N1 = 2.643 (7), Pb—N2 = 2.637 (7) Å] are significantly shorter than those in (2,6-Me₂C₆H₃S)₂Pb × 2py [2.689 (3) and 2.695 (3) Å], while the Pb—S distances [Pb—S1 = 2.650 (2), Pb—S2 = 2.653 (2) Å] are significantly longer [2.6078 (9) and 2.6079 (9) Å for (2,6-Me₂C₆H₃S)₂Pb × 2py]. This may be rationalized by considering the increased electron withdrawing ability of the C₆F₅ group in (I) versus the 2,6-Me₂C₆H₅ group in (2,6-Me₂C₆H₃S)₂Pb × 2py. The result is an effective increase in the Lewis acidity at the Pb centre, and shorter Pb—N Lewis acid-base bonding interactions. Very weak intermolecular Pb ··· S interactions [Pb—S1ⁱ = 3.618 (4), Pb—S2ⁱ = 3.614 (4) Å; (i) -1 + x, y, z; sum of van der Waals' radii = 3.8 Å] (Bondi, 1964; Brown, 1978) between adjacent molecules in (I) yield a one-dimensional polymeric structure (Fig. 2). These contacts are nearly trans to the short Pb—S bonds [S1—Pb—S2ⁱ = 166.75 (5)°, S2—Pb—S1ⁱ = 166.83 (5)°], yielding a distorted octahedral bonding arrangement at Pb. This weakly associated polymeric structure differs from that of (2,6-Me₂C₆H₃S)₂Pb × 2py, which is monomeric in the solid-state. Further, the structure possesses no intramolecular Pb ··· F contacts such as those observed in [(F₅C₆S)₂Pb]_n (Fleischer et al., 2006).

Experimental

Synthesis of (C₆F₅S)₂Pb × 2py: A solution of pyridine (0.520 g, 6.57 mmol) in thf (3 ml) was added dropwise to a stirred solution of (C₆F₅S)₂Pb (0.100 g, 0.165 mmol) in thf (5 ml) to give a cloudy pale green solution. The solution was stirred for 15 minutes and filtered. After 1 d at 25°C, colorless rod-like crystals of (I) were collected by suction filtration (0.100 g, 0.131 mmol, 79%). Anal. Calc. for C₂₁H₁₀F₁₀N₂PbS₂: C, 34.60; H, 1.32; N, 3.67. Found: C, 34.47; H, 1.05; N, 3.64. Mp 262°C. See expt further details section for spectroscopic data.